PSA

ABSTRACTS 1

1FATTY ACIDS IN PHOTOTROPHIC AND

MIXOTROPHIC

GYRODINIUM GALATHE-ANUM

(DINOPHYCEAE)

Adolf, J. E.

1

, Place, A. R.

2

, Lund, E.

2

, Stoecker,D. K.

1

, & Harding, L. W., Jr

1,3

1

Horn Point Lab, University of Maryland Center forEnvironmental Science, Cambridge, MD 21613 USA;

2

Center of Marine Biotechnology, Baltimore, MD 21202USA;

3

Maryland Sea Grant, University of Maryland,College Park, MD 20742 USA

Fatty acids were measured in

G. galathean

um growneither phototrophically, or mixotrophically with

Storeatula major

(Cryptophyceae) as prey.

G. galatheanum

,like many photosynthetic dinoflagellates, containshigh amounts of n-3 long-chain-polyunsaturated fattyacids (LC-PUFA) such as docosahexaenoic acid(DHA, 22:6n-3) and the hemolytic toxic fatty acid18:5n-3. We hypothesize that a benefit of phagotrophyin

G. galatheanum

is the acquisition of precursor lino-lenic acid (18:3n-3) that fuels LC-PUFA synthesis.Phototrophs grew at 0.37 d

2

1

, while mixotrophs grewat 0.40 d

2

1

with a feeding rate of 0.62 d

2

1

. Photosyn-thesis was lower in mixotrophs (3.7 pg C cell

2

1

h

2

1

)than phototrophs (4.9 pg C cell

2

1

h

2

1

). DHA levelswere higher in mixotrophs [3.7 (

1

/

2

0.11) pg cell

2

1

]than phototrophs [3.0 (

1

/

2

0.16) pg cell

2

1

] andprey [0.4 (

1

/

2

0.01) pg cell

2

1

]. 18:5n–3 levels [1.7(

1

/

2

0.03) pg cell

2

1

] were similar in phototrophsand mixotrophs. An intermediate in n-3 LC-PUFAsynthesis, 20:4n-3, accumulated in mixotrophs [0.6(

1

/

2

0.27) pg cell

2

1

] relative to phototrophs (notdetected) and prey [0.03 (

1

/

2

0.002) pg cell

2

1

]. Lowratios of linolenic acid to DHA in phototrophic

G.galatheanum

(0.14) relative to mixotrophic

G.galatheanum

(0.29) and prey (2.14) are consistent withsubstrate limitation of LC-PUFA synthesis in phototro-phs. Accumulation of 20:4n-3 suggests incompleteconversion of linolenic acid to DHA, possibly due toconditions in batch culture. We conclude that precur-sors for n-3 LC-PUFA biosynthesis in

G. galatheanum

may be acquired through ingestion of

S. major

, andmay partially control feeding/photosynthesis in mix-otrophic populations.

2SPECIES COMPOSITION AND SEASONALPERIODICITY OF MACROALGAL SPECIES INCORPUS CHRISTI BAY, TEXAS

Agan, J. C. & Lehman, R. L.

Department of Physical and Life Sciences, Texas A&MUniversity-Corpus Christi, 6300 Ocean Dr., CorpusChristi, TX 78412 USA

Benthic algal sampling from selected sites along Cor-pus Christi Bay and from one site at the Port Aransas,

Texas south jetty was completed between April 1999and February, 2000. Species composition, seasonal pe-riodicity, and fluctuations in temperature and salinitywere determined. This is the first comprehensivestudy of benthic macroalgae conducted in CorpusChristi Bay, which is shallow, turbid, and lacks naturalhard substrate. Man-made jetties are necessary forsuitable floral attachment. Macroalgae are affected bychanges in salinity as freshwater inflows are followedby periods of drought, which increase salinity. Theseeffects are most notable where freshwater enters atthe south end near Oso Bay and at the north end atNueces Bay. Previous Texas algal collections de-scribed species of

Enteromorpha, Ulva, Gelidium

, and

Gracilaria

as the most dominant plants of the area.This supports the current study with the additions of

Hypnea musciformis

and

Centroceras clavulatum.

Domi-nant plants at the Port Aransas jetty include

Ulva fasci-ata, Padina gymnospora

, and

Hypnea musciformis.

TheRhodophyta including

Gracilaria, Gelidium

, and

Centro-ceras clavulatum

dominate the bay and do so through-out the year. Chlorophytes, although few in speciesrichness, are important to benthic coverage and bio-mass. Phaeophyta are found predominantly at thePort Aransas jetty with

Sargassum

,

Dictyota dichotoma

,and

Petalonia fascia

being most abundant. A transitionoccurs in species composition as the water tempera-ture changes seasonally.

Hincksia, Ectocarpus

, and

Peta-lonia fascia

are found only during the cooler months.

3NEW AND RARE CHRYSOPHYTES FROMWYOMING AND COLORADO LAKES

Aguiar, R. & Kugrens, P.

Department of Biology, Colorado State University, FortCollins, Colorado 80523 USA

Colorado and Wyoming lakes with high pH valuesgenerally ranging from 8 to 10 are dominated by phy-toplankton belonging to the chrysophytes, diatomsand cryptomonads. Our studies on phytoplankton di-versity in Dowdy, South Delaney Buttes and CowdreyLakes in Colorado and Diamond and Twin ButtesLakes in Wyoming have yielded several isolates of rareor new chrysophytes. These isolates were examinedwith light microscopy, SEM, TEM, and novel informa-tion regarding their structure is presented. Proposednew species belong to the genera

Saccochrysis, Prymne-sium

and

Chrysochromulina.

Chrysophytes that were ex-amined for the first time include

Monochrysis aphanas-ter

,

Uroglenopsis

, and a mixotrophic species of

Ochromonas

, which ingests small diatoms. Probablenew species are the following:

Saccochrysis

sp. nov. dif-fers in chloroplast structure, cell shape and cell num-ber/colony, and absence of a posterior vacuole;

Prym-nesium

sp. nov. is the first freshwater form examinedwith EM and differs in scale morphology; and

Chryso-chromulina

sp. nov. is similar to

Chrysochromulina parva

but lacks scales. The ultrastructure of

M. aphanaster

is

2

PSA

ABSTRACTS

unique and appears to be a member of the Chryso-phyceae. It has two flagella, one of which is emergent,while the other is hidden within an invagination ofthe cytoplasm.

Diacronema

and

Sarcinochrysis

spp. fromthese lakes also were isolated and reinvestigated, andsome unique cellular features will be discussed.

4ALGAL COMMUNITY STRUCTURE OF THEEAST AND WEST FLOWER GARDEN BANKS,NORTHWESTERN GULF OF MEXICO

Albert, E. M. & Lehman, R. L.

Center for Coastal Studies, Texas A&M University-Corpus Christi, 6300 Ocean Drive, Corpus Christi, TX78412 USA

The algal communities of the Flower Garden BanksNational Marine Sanctuary have not been compre-hensively evaluated and only a few dominant macroal-gal species have been reported. This study utilizesboth destructive and non-destructive sampling tech-niques to characterize and taxonomically identify the‘algal mat’ community structure. The East and WestFlower Garden Banks are located on the outer conti-nental shelf approximately 200 km off the Texas-Loui-siana coastline. The average depth of both banks is100 m with the crest approximately 20 m from the sur-face. Harvest and photogrammetric samples were col-lected during two extended cruises to the Flower Gar-den Banks in October 1998 and March 1999. Forty,0.25-m

2

quadrats of standing stock material were ran-domly collected along with one hundred sixty-one0.25 m

2

photo-quadrats from an average depth of 27m. Photo-transparencies were projected to an actualsize grid with 25 random points. Four thousandtwenty-five transparency points were evaluated andused to calculate percent composition of algal cover.Harvest samples were used to characterize the “algalmat” composition, species richness, abundance, andbiomass. Forty-two species were identified from thesamples representing 14 Orders. The “red algal mat”was the dominant algal coverage comprising 38.4% ofall photogrammetric samples. This mat was primarilycomposed of members from the Order Ceramiales.

Centroceras, Ceramium

, and

Polysiphonia

comprised33.4% of the mat,

Anotrichium

and

Hypoglossum

,22.4%.

5THE PHYLOGENETIC RELATIONSHIPS OFTHE PHAEOTHAMNIOPHYCEAE, WITHCOMMENTS ON CERTAIN CAPSOID MEM-BERS OF THE CHRYSOPHYCEAE

Andersen, R. A.

1

, Bailey, J. C.

2

& Daugbjerg, N.

3

1

Bigelow Laboratory for Ocean Sciences, West BoothbayHarbor, ME 04575 USA;

2

Department of BiologicalSciences, University of North Carolina-Wilmington,

Wilmington, NC 28403 USA;

3

Department of Phycol-ogy, University of Copenhagen, Copenhagen, Denmark

The Phaeothamniophyceae was based upon ultra-structure, pigment analysis and

rbc

L gene sequences.Recently we have successfully obtained SSU rDNA se-quences from members of this relatively new class.These sequences corroborate the phylogenetic rela-tionship of the Phaeothamniophyceae as a close rela-tive of the Phaeophyceae and Xanthophyceae. Addi-tionally we show that the “walled”

Chrysocapsaepiphytica

is a synonmym of

Tetrasporopsis fuscescens

andbelongs in the Phaeothamniophyceae. Conversely,“wall-less” taxa such as

Chrysocapsa vernalis

,

Dermatochry-sis

, and

Chrysonebula

belong within the Chryso-phyceae. Furthermore, we suggest that the capsoid

Tetrachrysis dendroides

is a synonym of

Stichogloea globosa

and belongs within the Phaeothamniophyceae. Wewill also report new findings for other genera (e.g.

Phaeobotrys, Phaeothamnion, Phaeoschizochlamys, Stichog-loea

). It appears that the capsoid habit evolved inde-pendently in the Phaeothamniophyceae and theChrysophyceae, thus providing a new example of con-vergent evolution for thallus organization.

6RELATIVE IMPORTANCE OF RECRUIT-MENT VERSUS REGENERATION IN MAIN-TAINING THE POPULATIONS OF

SAR-GASSUM HENSLOWIANUM

IN PING CHAU,HONG KONG

Ang, P. O.

Department of Biology, The Chinese University of HongKong, Shatin, N.T., Hong Kong SAR, China

Populations

S. henslowianum

dominate the shallowsubtidal waters of Ping Chau Island, Hong Kong. Astudy was carried out to evaluate the relative impor-tance of recruitment vs regeneration from the hold-fast in the maintenance of these populations. Thenumber of recruits on clearings, artificial and naturalsubstrata as well as the density of the natural popula-tions were evaluated on a periodic basis from March1998 to March 2000. The results indicated that al-though up to 85 to 100% of the individuals of this spe-cies may be reproductive during the winter reproduc-tive season (Nov to Feb), only up to a maximum meandensity of 17 recruits 0.25 m

2

2

were found in thecleared areas or artificial substrata provided. Lessthan 10% of these eventually survived the followinggrowth season. In the natural stands, new individuals(recruits) constituted only less than 15% of the meandensity. The number of new recruits was particularlylow around older individuals. Thus, these populationswere mainly made up of older individuals regenerat-ing from their perennating holdfasts. It appears thatregeneration from the holdfast is a far more impor-

PSA

ABSTRACTS 3

tant strategy than recruitment in the maintenance ofthese populations.

7

IN VIVO

CHARACTERIZATION OF THE DIA-TOM MULTIPARTATE PLASTID TARGET-ING SIGNAL

Apt, K. E.

1

, Zaslavskaia, L.

1

, Lippmeier, J. C.

1

,Lang, M.

2

, Grossman, A. R.

3

, & Kroth, P. G.

2

1

Martek Biosciences Corp., Columbia, MD, USA;

2

Institut fur Biochemie der Pflanzen, Heinrich-Heine-Universitat, Dusseldorf, Germany; 3Carnegie Institu-tion of Washington, Department of Plant Biology,Stanford, CA, USA

Diatoms and related algae have plastids that are sur-rounded by four membranes. The outer two mem-branes are continuous with the endoplasmic reticu-lum and the inner two membranes are analogous tothe plastid envelope membranes of higher plants andgreen algae. Thus the plastids are completely com-partmentalized within the ER membranes. The target-ing presequences for nuclear-encoded plastid pro-teins have two recognizable domains. The first domainis a classic signal sequence, which presumably targetsthe proteins to the endoplasmic reticulum. The sec-ond domain has characteristics of a transit peptide,which targets proteins to the plastids of higher plants.To characterize these targeting domains, the prese-quence from the nuclear-encoded plastid proteinAtpC was utilized. A series of deletions of this prese-quence were fused to Green Fluorescent Protein(GFP) and transformed into cells of the diatom, Phae-odactylum tricornutum. The intracelluar localization ofGFP was visualized by fluorescence microscopy. Thiswork demonstrates that the first domain of the prese-quence is responsible for targeting proteins to the ERlumen and is the essential first step in the plastid pro-tein import process. The second domain is responsi-ble to directing proteins from the ER and through theplastid envelope and only a short portion of the tran-sit peptide-like domain is necessary to complete thissecond processing step. In vivo data generated fromthis study in a fully homologous transformation sys-tem has confirmed Gibbs’ hypothesis regarding amultistep import process for plastid proteins in chro-mophytic algae.

8THE ROLE OF CARBONIC ANHYDRASE INTHE FORMATION OF MOUGEOTIA (CHARO-PHYCEAE) BLOOMS IN ACIDIC ENVIRON-MENTSArancibia-Avila, P. E.1, Coleman, J. R.2, Russin,W. A.3, Wilcox, L. W.4, Graham, J. M.4 & Graham,L. E.4

1Departamento de Ciencias Básicas, Universidad delBío-Bío, Chillán, Chile, 2Department of Botany, Uni-versity of Toronto, Toronto, ON M5S 3B2 Canada,3Department of Plant Pathology, University of Wiscon-sin, Madison, WI 53706 USA, 4Department of Botany,University of Wisconsin, Madison, WI 53706 USA

Mougeotia sp, a dominant component of a metaphyticalgal bloom-forming alga in an experimentally acidi-fied lake (Little Rock Lake, Vilas Co. WI) was isolatedto analyze pH effects on carbonic anhydrase (CA) ac-tivity, localization, and algal morphology. A potentio-metric method was used to assess internal and externalCA activities using two CA inhibitors, ethoxyzolamide(EZA) and acetazolamide (AZA) in cultures grown atpH 5 and pH 8. External and total CA activities at pH8 were significantly greater than those at pH 5, but in-ternal CA activities were not significantly different atboth pH levels. The non-penetrating inhibitor AZAinhibited external CA activity at pH 8, whereas EZA,which inhibits internal CA activity in some green al-gae, did not inhibit Mougeotia CA activity, possibly be-cause of permeability problems. Ultrastructural im-munogold labeling with a polyclonal antibody forChlamydomonas external CA suggested that an antigen-ically-similar enzyme was located in the periplasmicspace and inflated end walls of Mougeotia grown atboth pHs. This antibody, labeled the Mougeotia chlo-roplast, but not the pyrenoid and cytoplasmic periph-eral regions. Activity measurements, inhibitor results,and localization data were consistent with the opera-tion of a carbon concentrating mechanism (CCM) atboth pH levels. Growth form, cell dimensions, chloro-plast morphology, and cell wall ultrastructure weresignificantly different in cultures grown at both pHlevels. These features probably contributed to theability of Mougeotia to form blooms in acidified waters.A polyclonal antibody to pea chloroplast CA did notlabel Mougeotia, suggesting evolutionarily significantdifferences in the plastid CA systems of this alga andhigher land plants.

9THE PRESENCE OF CALLOSE IN THE PRI-MARY ZYGOTE WALL OF CHLAMYDOMONASMONOICA AND THE EFFECTS OF ITS DEGRA-DATION ON ZYGOTE DEVELOPMENTBai, M. S. & VanWinkle-Swift, K. P.Department of Biological Sciences, Northern ArizonaUniversity, Flagstaff, AZ 86011

Chlamydomonas monoica constructs a temporary pri-mary wall around its developing zygotes. This studyaimed to confirm callose as a component of the pri-mary wall, as well as to note the effects of primary walldegradation on zygote development. Glucanase, spe-cific for the b-1,3 glycosidic bonds comprising callose,was added to mating media at concentrations ranging

4 PSA ABSTRACTS

from 5 to 1 mg ml21 and light microscope observa-tions were made as the zygotes developed. The overallhealth of the zygotes was assessed by comparing theirability to germinate after exposure to chloroform va-pors. The bright staining of the primary wall withaniline blue, specific for b-1,3 polysaccharides, sug-gested the presence of callose. This was further sup-ported by the adverse effects of glucanase on zygotedevelopment. After mating, declining levels of intactzygotes were found as their maturation continued,and dead immature zygotes accumulated in thetreated cultures. Twelve days after mating, when thezygotes were plated for germination, fully mature zy-gotes were identified in only the lowest of the six en-zyme concentrations. In addition, germinating zy-gotes from the treated cultures showed increasedsensitivity to killing by chloroform vapors relative tountreated zygotes. These results suggest that callose isa key component in the primary zygote wall, and thatits degradation negatively affects zygote maturation.Electron microscopy will be used to help determinewhether structural defects in the primary wall occur asa result of glucanase treatment, and whether such de-fects affect secondary zygospore wall assembly.

10PHYLOGENY AND CLASSIFICATION OFREEF-BUILDING CORALLINE ALGAE (COR-ALLINALES, RHODOPHYTA)Bailey, J.C. & Freshwater, D.W.Department of Biological Sciences and Center for Ma-rine Science, The University of North Carolina atWilmington, Wilmington, NC 28403 USA

The Corallinales includes ca. 40 genera of calcifiedred seaweeds. Species are of two distinct morpho-types; those that possess genicula (uncalcified nodes)and those that lack genicula. Most nongeniculate spe-cies take the form of crusts. The presence (or ab-sence) of genicula, secondary pit connections, andtetrasporangial conceptacle features have tradition-ally been used as key characters for delimiting coral-line subfamilies. In this study, nuclear encoded 18Sand 26S rRNA gene sequences were determined andused to reexamine relationships among corallinetaxa. Separate and combined phylogenetic analyses ofthese data yielded similar trees in which four majorlineages are resolved. Heydrichia and Sporolithon(Sporolithaceae) are positioned at the base of thetree and appear to be distantly related to other spe-cies examined. Within the Corallinaceae, the nongen-iculate Melobesioideae is resolved as a monophyleticgroup. All members of this subfamily produce mutipo-rate tetraspoangial conceptacles. The Corallinoideae,which are characterized by unizonate genicula, areresolved as sister to a clade containing species placedin the Lithophylloideae, Mastophoroideae and Me-tagoniolithoideae. The molecular data indicate thatgeniculate and nongeniculate species characterized

by the presence of secondary pit connections areclosely related. For example, both data sets robustlysupport a sister taxon relationship between Amphiroaand Titanoderma. Our results indicate that: 1) all taxain which secondary pit connections are presentshould be referred to the Lithophylloideae and, 2)genicula are nonhomologous structures that are inde-pendently derived in Amphiroa, Lithothrix, Metagonioli-thon and the last common ancestor of the Coralli-noideae.

11MOLECULAR SYSTEMATICS OF THE XAN-THOPHYCEAEBailey, J. C.1, McElhinney, A. L.1 & Andersen, R. A.21Department of Biological Sciences, UNC-Wilmington,Wilmington, NC 28403 USA; 2Bigelow Laboratory forOcean Sciences, West Boothbay Harbor, ME 04575USA

Species belonging to the Xanthophyceae have tradi-tionally been classified in six (or seven) orders corre-sponding to amoeboid, coccoid, filamentous, mona-doid, palmelloid and siphonous lines of descent. Wehave determined plastid rbcL and nuclear 18S rRNAgene sequences for selected coccoid, filamentous andsiphonous species. Phylogenetic trees inferred fromthese data indicate that the orders Mischococcales(coccoid) and Tribonematales (filamentous) are notmonophyletic. Instead, our results indicate that coc-coid and filamentous life forms have arisen indepen-dently in different xanthophyte lineages. Some coc-coid and filamentous species are resolved as closeallies. For example, in our analyses coccoid and fila-mentous species possessing bipartite cell walls (e.g.,Bumilleria, Ophiocytium, Tribonema, Xanthonema) forma distinct and previously unrecognized lineage withinthe class. The phylogenetic positions of Asterosiphon,Botrydium and Vaucheria are not robustly resolved, butour data suggest that these siphonous xanthophytesprobably do not form a monophyletic group. Our re-sults imply that Vaucheria is only distantly related toother xanthophytes we have examined. Nucleotide se-quence divergence values among Vaucheria specieswere found to be equal to, or greater than, those ob-served between other xanthophyte species that areclassified in different families or orders. Furthermore,our trees do not always support the infrageneric sys-tem of classification for Vaucheria species, which isbased primarily upon antheridial features.

12CELL CYCLE REGULATORS IN THE FLOR-IDA RED TIDE DINOFLAGELLATE, GYMNOD-INIUM BREVEBarbier, M., Leighfield, T. A., & Van Dolah, F. M.

PSA ABSTRACTS 5

Marine Biotoxins Program, Center for Coastal Envi-ronmental Health and Biomolecular Research, NOAA,National Ocean Service, Charleston, SC 29412 USA

The diel cycle is a key regulator of the cell cycle inmany dinoflagellates, and may play a rate limiting rolein bloom formation. Diel phasing of the cell cycle inthe Florida red tide dinoflagellate, Gymnodinium breveDavis was previously described in our laboratory. Incultures grown on a 16:8 light:dark cycle, S-phase be-gan 6–8 h into the light phase, and mitosis followed12–14 h later. The dark/light “dawn” transition wasfound to provide the diel cue that serves to entrainthe G. breve cell cycle. However the cell cycle mecha-nisms and regulators acted upon by this cue arepoorly understood in dinoflagellates. The cell cycleregulatory complex, CDK1-cyclinB, is therefore cur-rently being investigated. Cyclin dependent kinase(CDK) was first identified in G. breve using two ap-proaches: (1) identification of a 34 kDa protein im-munoreactive to an antibody raised against a con-served amino acid sequence unique to the CDKprotein family (PSTAIR) and (2) inhibition of the cellcycle by olomoucine, a selective CDK inhibitor. Sev-eral approaches are currently being employed in or-der to describe its partner, cyclin B: (1) PCR on ge-nomic DNA with primers deduced from known cyclinbox sequences, (2) G. breve expression library screen-ing with an antibody raised against the fission yeast cy-clin B (3) western blot analysis on whole protein ex-tracts and cyclin B immunoprecipitated proteins.Current work focuses on the differential expression ofthe cyclin B homologue in G. breve during its cell cycleand its relation to diel cycle control.

13PHYTOFLAGELLATES OF THE SALTON SEA:CRYPTOPHYCEAEBarlow, S.B.1 & Kugrens, P.21Electron Microscope Facility, San Diego State Univer-sity, San Diego CA 92182 USA; 2Department of Biology,Colorado State University, Fort Collins, Co 80523 USA

The species composition of phytoflagellates in the Sal-ton Sea has recently been the subject of intense inves-tigation as part of an analysis of the Salton Sea ecosys-tem. The Salton Sea, an inland sea occupying 980 km2

in southern California, has become a major stoppingpoint for migratory birds along the Pacific Flyway.The increasing salinity of the sea, currently at 44 gmL21, and its eutrophic condition (average depth isnine meters, with a high nutrient load contributed byagricultural drainage from the surrounding farm-lands) have contributed to a stressed ecosystem. Mas-sive fish kills and bird kills, including such endan-gered birds as the brown pelican, have become arecurring problem. Although previous investigationshave noted the presence of at least two phytoflagel-

lates implicated in fish mortality, little attention hasbeen paid the to the identities of the smaller flagel-lates observed growing in the sea and their possiblecontribution to the fish and bird population mortal-ity. Using freshly collected field samples as well as en-richment culture techniques, we report the occur-rence of several genera of cryptomonads in the SaltonSea, including representatives from the genera Chroomo-nas, Hemiselmis, Leucocryptos, Plagioselmis, Storeatula andTeleaulax.

14STRUCTURE, COMPOSITION AND BIOGEN-ESIS OF PRASINOPHYTE SCALESBecker, B.Botanical Institute, University of Cologne, Gyrhofstr.15, 50931 Cologne, Germany

The cell body and flagellar surfaces of prasinophytesare covered by non-mineralyzed scales. Scales consistmainly of acidic polysaccharides containing largeamounts of 2-keto sugar acids. Glycoproteins are mi-nor components and probably mainly involved in me-diating scale-subunit and scale-membrane interac-tions. In thecate prasinophytes the cell body scalescoalesce to form a rigid cell wall, generally known as atheca. We have studied the polysaccharides and glyco-proteins of the thecate prasinophytes Tetraselmis stri-ata and Scherffelia dubia over the last years. New resultsregarding the structure of carbohydrates and proteinswill be presented.

15PHYLOGENY OF ATLANTIC SPECIES OFGRACILARIACEAE (RHODOPHYTA) BASEDON SMALL SUBUNIT RIBOSOMAL GENESEQUENCINGBellorin, A. M.1,2, Oliveira, M. C.1 & Oliveira, E. C.11Dept. de Botânica, Instituto de Biociências, Univer-sidade de São Paulo, Caixa Postal 11461, São Paulo,Brazil; 2Dept. de Biologia, Universidad de Oriente, AP245 Venezuela.

The complete small subunit ribosomal nuclear gene(ssu rDNA) sequence was determined for nine speciesof Gracilaria and one species of Gracilariopsis which arecommon on the American Atlantic waters. The se-quences were aligned using the secondary structure asreference, including the published sequences of nineother species of Gracilariaceae. A matrix of 1736 siteswas constructed with a proportion of 91% invariablesites and very few assumed indels events. All the in-ferred trees show three main lineages: 1) the stronglydivergent lineages of Gracilariopsis; 2) the austral gen-era Curdiea/Melanthalia; and 3) the lineage ofGracilaria sensu stricto. The later encompasses the fol-lowing groups: 1) Gracilaria chilensis from the Pacific

6 PSA ABSTRACTS

ocean; 2) a group of cylindrical tropical species with“henriquesiana” spermatangial type; 3) a group ofwarm temperate cylindrical species with “verrucosa”spermatangial type; and 4) a group of flattened tropi-cal species with mainly “textorii” spermatangial type.The relationship of a species described as Gracilariapauciramosa from Venezuela was not inequivocallysolved. The inferred phylogenetic groups are congru-ent with morphology and quality of agar.

16ARE SPERM LIMITING IN THE SEA?Berndt, M. L. & Brawley, S. H.School of Marine Sciences, University of Maine, Orono,ME 04469 USA

The reproductive success of marine species with ex-ternal fertilization depends on environmental condi-tions during gamete release. There is special interestpresently in whether water motion causes sperm limi-tation under natural conditions. We investigated ga-mete release of Fucus vesiculosus from an exposedshore to ascertain: 1) when gametes are released dur-ing the tidal cycle, 2) when fertilization occurs, and 3)what the natural sperm:egg ratios are. Water sampleswere collected and concentrated over five minutes ev-ery half hour off Pemaquid Point, ME from three rep-licate sites within each of two locations using a pump-filter device. Immunofluorescence microscopy re-vealed that gamete release occurred only on the twocalmest spring tides. Sperm became present in the wa-ter column at the same time as oogonia (30 min21 hprior to high tide [HT]) and reached peak concentra-tion at exactly HT. The sperm:egg ratio was 76:1 on 8Oct 1999 and 21:1 on 8 Nov 1999 at exactly 30 minprior to HT and dropped sharply after HT. Gametescontinued to be collected for several hours after HTbut analysis of pronuclear position in aceto-iron-he-matoxylin stained eggs revealed that all fertilizationoccurred at approximately HT. We modelled the totalnumber of days when reproduction was possible usingthese results and wind and wave data from the Na-tional Data Buoy Center. Our research provides evi-dence that gamete release by F. vesiculosus occurs atslack HT on calm days and that sperm are not a limit-ing factor in fertilization for this species.

17PATTERNS OF INTERSPECIFIC INTERAC-TIONS IN THE ULVA-DOMINATED INTER-TIDAL COMMUNITY IN A SOUTHERNCOAST OF KOREABhang, Y. J. & Kim, J. H.Department of Biological Science, Sungkyunkwan Uni-versity, Suwon, 440-746 Korea

In the southern coast of Korea, rocky intertidal zoneswhere green tide commonly occurs are dominated by

Ulva pertusa, red algal turf (a mixed stand of Gigartinaintermedia and Gigartina teedii) and species of Entero-morpha with highly opportunistic occurrence. To in-vestigate their interspecific interactions, a field exper-iment was carried out using press effect of one speciesremoval from permanent plots (20 x 20cm) set up ontwo different tidal heights. Mechanisms of interactionwere also attempted using artificial plants to test thepossible effects of shading, scouring, allelopathy of U.pertusa on the turf algae. The turf-forming red algaelowered the abundance of U. pertusa presumably by in-hibiting the recruitment of U. pertusa; this effect wasconsistent along the tidal height. However, thegreater abundance of Enteromorpha was observed inthe presence of turf in the upper zone, indicating apositive effect of turf on Enteromorpha. Once U. pertusawas successfully recruited and grown to the adultplant, it inhibited the growth of turf by shading,which was effective both in winter and summer re-gardless of desiccation stress. No scouring and allelo-pathic effects of U. pertusa on the turf were detected.When an open substrate was provided, Enteromorphacolonized the space faster than any other species inthe upper zone, but the turf was the fastest one fol-lowed by U. pertusa and Enteromorpha in the lowerzone. Results indicated that patterns of interactionrepresented a complex network with no ultimate win-ner and the outcomes of interaction varied over timeand space.

18USING RDNA GENES TO UNDERSTAND THEORIGIN AND EVOLUTION OF SPLICEOSO-MAL AND GROUP I INTRONSBhattacharya, D.1, Lutzoni, F.2, Reeb, V.2, Simon,D.1, Fernandez, F.2, & Friedl, T.31Department of Biological Sciences, University of Iowa,Iowa City, IA 52242 USA; 2Department of Botany,The Field Museum of Natural History, Chicago, IL60605 USA; 3Abt. Experimentelle Phykologie und Sam-mlung von Algenkulturen, Universität Göttingen,37073 Göttingen, Germany

Ribosomal DNA genes in lichen algae and lichenfungi are astonishingly rich in spliceosomal andgroup I introns. We use phylogenetic, secondarystructure, and biochemical analyses to understand theevolution of these introns. Despite the widespread dis-tribution of spliceosomal introns in nuclear pre-mRNA genes, their general mechanism of origin re-mains an open question because few proven cases ofrecent and pervasive intron origin have been docu-mented. The lichen introns are valuable in this re-spect because they are undoubtedly of a “recent” ori-gin and limited to the Euascomycetes. Our analysessuggest that rDNA spliceosomal introns have arisenthrough aberrant reverse-splicing (in trans) of free

PSA ABSTRACTS 7

pre-mRNA introns into rRNAs. We propose that thespliceosome itself (and not an external agent; e.g.transposable elements, group II introns) has givenrise to the introns. The rDNA introns are found mostoften between the flanking sequence G (78%) - in-tron-G (72%), and their clustered positions on sec-ondary structures suggest that particular rRNA re-gions are preferred sites (i.e., proto-splice sites) forinsertion. Mapping of intron positions on the newlyavailable tertiary structures show that they are foundmost often in exposed regions of the ribosomes. Thisagain is consistent with an intron origin through re-verse-splicing. Remarkably, the distribution and phy-logenetic relationships of most group I introns in nu-clear rDNA genes are also consistent with a reverse-splicing origin. These data underline the value of li-chens as a model system for understanding intron ori-gin and stress the importance of RNA-level processesin the spread of these sequences in nuclear coding re-gions.

19INTRA-CELLULAR AND EXTRA-CELLULARTOXINS IN THE RED TIDE DINOFLAGEL-LATE, GYMNODINIUM BREVEBlum P. C., Henry M. S., Pierce R. H., Payne S. R.,& Lyons, J. I.Mote Marine Laboratory, 1600 Ken Thompson Park-way, Sarasota, FL 34236 USA

The marine dinoflagellate, Gymnodinium breve (Davis),produces several neurotoxins that cause neurotoxicshellfish poisoning (nsp), massive fish kills and respi-ratory irritation in marine mammals and humans.The common method for discerning toxic levels of G.breve for public health advisories is enumeration oflive cells in a given water mass. In this study, labora-tory cultures, as well as natural blooms, were added toa stirred ultra-filtration cell concentrator to separateviable cells containing intra-cell toxins from ambientwater containing extra-cell toxins. Methods were vali-dated using various mixtures of lysed and whole G.breve laboratory culture. Extractions and recovery ofbrevetoxins were done using a C-18 bonded-phaseglass fiber extraction disc eluted with methanol. TotalPbTx toxin concentrations were quantified by HPLC/UV using a C-18 column and an 85:15 methanol:water(1 ml min21) isocratic elution at 215 nm. This methodof separation and extraction was subsequently appliedto water samples collected during natural bloomsalong two different areas of the Florida Gulf coast.The results indicated that early stages of G. breveblooms contained primarily intra-cell toxins with extra-cell toxins increasing as the bloom progressed, eventhough very few viable G. breve cells were present. Thissuggests that enumeration of cells alone may be insuf-ficient and additional toxin quantitation is necessary.

20A RE-EVALUATION OF CORALLINE REDALGAL TAXONOMY USING ULTRA-STRUC-TURAL INFORMATIONBroadwater, S. & Scott, J.Department of Biology, College of William and Mary,Williamsburg, VA 23187 USA

Two competing subfamily classification schemes forthe red algal family Corallinaceae are in generalagreement with respect to the taxonomic value of cellconnection type (cell fusions versus secondary pitconnections), but differ over the relative weight givento the character of genicular presence/absence. Con-sequently, Corallinoideae, Melobesioideae and Metag-oniolithoideae are recognized as distinct subfamilies.One scheme subsumes the geniculate Amphiroideaeinto the nongeniculate Lithophylloideae (based onthe common presence of secondary pit connections)and the nongeniculate Mastophoroideae into thegeniculate Corallinoideae (based on the commonpresence of cell fusions); the other maintains thesesubfamilies as four separate lineages. Small subunitrRNA gene sequence data confirms the integrity ofCorallinoideae and Melobesioideae and fully supportsa revised classification subsuming Amphiroideae intoLithophylloideae. Surprisingly, Mastophoroideaeand Metagoniolithoideae (cell fusions) have a closeraffinity to the emended Lithophylloideae (secondarypit connections) than with Corallinoideae (cell fu-sions). These preliminary results cast doubt on thevalue of using cell connections as a primal character.From ultrastructural investigations of 28 coralli-noidean genera, including seven mastophoroideangenera and two lithophylloidian genera, it appearsthat the presence/absence of an electron- dense ma-terial (EDM) surrounding nuclei during sporogenesisis a more reliable indicator of subfamily affiliationthan cellular connections. Our findings support therevised classification of Lithophylloideae and suggestscloser affinity to Lithophylloideae (secondary pit con-nections, no EDM) than to Corallinoideae (cell fu-sions, EDM). However, EDM data indicates that Mas-tophoroideae may be polyphyletic as three generahave EDM and four do not.

21PORPHYRA SUBORBICULATA, PORPHYRA CAR-OLINENSIS AND PORPHYRA LILLIPUTIANA -THREE NAMES FOR ONE SMALL PORPHYRABroom, J. E.1, Nelson, W. A.2, Jones, W. A.1, Yarish,C.3, Aguilar Rosas, R.4, & Aguilar Rosas, L. E.41Department of Biochemistry, University of Otago, POBox 56, Dunedin, New Zealand; 2Museum of NewZealand Te Papa Tongarewa, PO Box 467, Welling-ton, New Zealand; 3Department of Ecology and Evolu-

8 PSA ABSTRACTS

tionary Biology, University of Connecticut, 1 Univer-sity Place, Stamford, CT 06901 USA; 4Facultad deCiencias Marinas, Universidad Autonoma de BajaCalifornia, Apartado Postal 453, Ensenada, BajaCaliornia, México

The genus Porphyra is ancient, successful, and mor-phologically simple. Its members provide a particularchallenge to systematists who must decide whethershared features are a result of homoplasy, or reflectrecent common ancestry. Three species of diminutivePorphyra with widespread geographic origins sharemany common morphological features: P suborbiculataKjellm. has been reported from the west Pacific andIndian Oceans, P. carolinensis Coll et J. Cox from thewest Atlantic, and P lilliputiana W. A. Nelson, G.A.Knight et M. W. Hawkes from New Zealand. Com-parison of 18S rDNA sequence data from small Por-phyra thalli from Mexico, Japan, New Zealand, Austra-lia and Connecticut indicate that these three taxa infact belong to one cosmopolitan species, which is dis-tributed over three oceans and two hemispheres.Analysis of sequence data from introns present in the18S rDNA and from the ITS region suggest that thisdistribution may be linked to human activity, andraises the question of to which geographic locality thisentity is truly endemic?

22ALGAE AS USEFUL TOOLS IN CELLULOSERESEARCHBrown, Jr., R. M.Section of Molecular Genetics and Microbiology, Schoolof Life Sciences, The University of Texas at Austin,Austin, TX 78712 USA

This presentation will review the 1976 discovery of theenzyme complex in cellulose biosynthesis in Oocystisapiculata. A linear terminal complex (TC) was foundto be associated with a microfibril, and from otherfreeze fracture applications, TCs have been found inmany different algal genera. In fact, the algae havethe most diverse and complex TCs among all organ-isms. TC diversity in terms of the evolution of cellu-lose biogenesis will be discussed. Combining the latestinformation from biochemistry and molecular genet-ics, the multiplicity of cellulose biogenesis will be re-viewed. Cellulose molecular weight, crystalline struc-ture, and mode of glycosylation for polymerformation all indicate that cellulose biogenesis is anextremely complex process. Major questions still re-main, and the enzymes for cellulose biosynthesis haveyet to be crystallized and their structure elucidated;however, the wealth of new information on cellulosestructure and biosynthesis from algae to vascularplants, including bacteria and tunicates, all point to avery exciting and useful area of research. The algae

have played key roles in our understanding of na-ture’s most abundant macromolecule.

23CHARACIOCHLORIS AND CHARACIOSIPHONFORM A SISTER GROUP TO THE“DUNALIELLA” LINEAGEBuchheim, M. A. & Buchheim, J. A.Department of Biological Science, The University ofTulsa, 600 South College Avenue, Tulsa, Ok 74104USA

The freshwater green algal genera, Characiochloris andCharaciosiphon, are distinctive taxa for which no clearconsensus exists regarding phylogenetic placement.Characiochloris is an epiphytic unicell that exhibitsmultiple (.2), scattered contractile vacuoles through-out the cytoplasm of the vegetative cell. AlthoughCharaciochloris has been placed in the Tetrasporales bymost systematists, the uncertain status of this green al-gal order raises questions regarding the position ofCharaciochloris. Characiosiphon, a coenocytic freshwaterorganism, has been linked to another freshwater co-enocyte, Protosiphon. However, multiple chloroplasts,greater thallus size, and a strictly aquatic life historyfor Characiosiphon have led to comparisons with caul-erpalean ulvophytes. Phylogenetic analysis of 18S and26S rDNA data was undertaken to test hypotheses ofrelationship for Characiochloris and Characiosiphon. Re-sults from molecular phylogenetic analyses stronglysupport a sister relationship for Characiochloris andCharaciosiphon. In addition, the Characiochloris/Charac-iosiphon clade is resolved as a sister group to the “Du-naliella” lineage of the Chlamydomonadales that in-cludes Ascochloris, Chlorogonium, Dunaliella, Haematococcus,Protosiphon and Spongiochloris. These results furthersupport the hypothesis that the “Dunaliella” clade in-cludes the majority of taxa that exhibit multiple con-tractile vacuoles. Moreover, these results support aninterpretation of the Characiosiphon coenocyte as amodified zoosporangium.

24PSEUDOFILAMENTOUS GREEN ALGAE FORMINDEPENDENT CHLOROPHYTE AND STREP-TOPHYTE LINEAGESBuchheim, M. A. & Buchheim, J. A.Department of Biological Science, The University ofTulsa, 600 South College Avenue, Tulsa, Ok 74104USA

The pseudofilamentous condition in green algae hasbeen characterized as the formation of a linear arrayof autospores. Although it is likely that this character-ization will be found to be an over-simplification, itserves as a logical starting point for a study of diversityamong pseudofilamentous taxa. Therefore, given that

PSA ABSTRACTS 9

molecular phylogenetic analyses have revealed thatcoccoid, autospore-formers are found in a number ofindependent green algal lineages, it is reasonable toexpect that pseudofilamentous taxa are likely to befound in a number of distinct lineages. In order totest this hypothesis, data from the nuclear-encoded18S r RNA gene were collected from several pseudofil-amentous, green algal genera (Geminella, Gloeotila,Hazenia, Interfilum, Microspora, and Sphaeroplea) and in-corporated into an 18S rRNA database of chlorobionttaxa. Results from phylogenetic analyses of these datasupport (1) an alliance of Interfilum, two Geminella iso-lates, and Klebsormidium within the streptophyte lin-eage, (2) an alliance of two Geminella isolates andMicrospora as a sister group to the ulvophycean/chlo-rophycean/trebouxiophycean clade or as a sistergroup to trebouxiophycean taxa, (3) an alliance ofHazenia with ulotrichalean taxa, (4) of Gloeotila withtrebouxiophycean taxa and (5) an alliance of Sphaero-plea with chlorophycean taxa. These data confirm thatthe filamentous condition has evolved in a numberof independent lineages. Moreover, these data fur-ther illustrate that the extent of molecular varia-bility within the green algae is far from fully appre-ciated.

25THE EFFECT OF NITROGEN SOURCE ONTHE GROWTH AND TOXICITY OF THREEPOTENTIALLY HARMFUL DINOFLAGEL-LATESBurns, C. L.1,2, Pennock, J. R. 1,2,3, Lores, E. M.4,& Greene, R. M.41Dauphin Island Sea Laboratory, 101 Bienville Blvd,Dauphin Island, AL 36528 USA; 2University of SouthAlabama, Department of Marine Sciences, Mobile ALUSA; 3University of Alabama, Department of Biologi-cal Sciences, Tuscaloosa, AL USA; 4U. S. Environmen-tal Protection Agency, Gulf Ecology Division, GulfBreeze, FL USA 32561

Increases in population and agriculture in coastal ar-eas can result in increased nutrient inputs and alter-ations in the ratios of organic to inorganic nutrientsin coastal waters. Such changes in coastal nutrient re-gimes can affect phytoplankton community structureby creating conditions favorable for growth and domi-nance of algae that were not dominant before. The ef-fect that changes in ratios and concentrations of nu-trients have on toxicity of harmful algal species is notwell known. There seems to be a relationship; how-ever, between nutrient stress and toxin productionamong harmful phytoplankton producing low-N tox-ins, e.g. Diarrhetic Shellfish Poisoning (DSP) toxins.Even less is known about the relationship between or-ganic nutrient uptake and toxin production. Benthicspecies and species in coastal areas are probably ex-posed to greater fluxes of dissolved organic nitrogen

(DON). In this study, benthic and planktonic speciesof Prorocentrum were grown on L1 media with the soleN-source varying among treatments as nitrate, ammo-nium, urea, L-glutamic acid, and high molecularweight natural DON. An ELISA specific to the DSPtoxins, okadaic acid and 35-methylokadaic acid, wasused to determine toxin production by each specieswhen grown on the different N sources. Preliminaryresults indicate that some organic forms of N supportgrowth as well as inorganic forms for Prorocentrum min-imum, P. mexicanum, and P. hoffmannianum.

26CULTIVATION STUDIES OF GIGARTINASKOTTSBERGII IN SOUTHERN CHILEBuschmann, A. H.1, Correa, J. A.2 & Wester-meier, R. 31Dep. Acuicultura, Universidad de Los Lagos, Casilla933, Osorno, Chile; 2Dept. Ecolog’a, P. UniversidadCatlica de Chile, Santiago, Chile; 3Universidad Aus-tral de Chile, Puerto Montt, Chile

In Chile, the demand for carrageenophytic algae hasincreased significantly in recent years. The preferredspecies is Gigartina skottsbergii, with landings of 26,181tons in 1998. To avoid a possible overexploitation thedevelopment of cultivation technologies is needed. Inthis study we present a critical view of published andnew information to propose the best culture strategyfor this species. The results indicate that viable sporesare seasonally available only during winter, with tet-raspore germination rates of ca. 40%. Germination ofcarpospospores is lower than 20%. Growth in tankscan be as high as 1% day21 and high nutrient concen-trations (N and P) must be added. Gigartina alsopresent a high and unique regeneration capacity.Field experiments indicate that Gigartina can be cul-tured in rope systems, where the inoculum can be tis-sue fragments. These results indicate that vegetativepropagation techniques can be used for the massiveculture of Gigartina, but selection of a high growingstrain remains as one of the future challenges.

27MONITORING THE PERSISTENCE OFGIANT KELP AROUND SANTA CATALINAISLAND USING A GEOGRAPHIC INFORMA-TION SYSTEMBushing, W. W.Science, Education and Ecological Restoration, SantaCatalina Island Conservancy, P. O. Box 2739, Ava-lon, CA 90704 USA

Geographic information systems (GIS) facilitate mon-itoring and analysis of population distributions at spa-tial and temporal scales differing from those em-

10 PSA ABSTRACTS

ployed in conventional field monitoring. This studyutilizes a GIS-based gap analysis of a network of ma-rine reserves around Santa Catalina Island relative tothe regional ecology, disturbance regime, and persis-tence of giant kelp (Macrocystis pyrifera), a keystonespecies in the nearshore, marine environment. Cat-alina’s orientation and greatly-dissected coastline cre-ate diverse microhabitats with respect to storm expo-sure, temperature, light regime and topographicfactors. GIS overlay methods applied to multi-tempo-ral kelp distribution maps generated a model repre-senting the spatial “persistence” of kelp. Correlationsbetween the kelp’s geographic distribution and persis-tence, the disturbance regime and physical variablesconferring resistance to or recovery from it weredrawn. This analysis identified regions of persistentkelp under disturbance regimes markedly differentfrom those in the existing reserves, suggesting the des-ignation of additional reserves in unprotected areas isecologically warranted.

28EFFECT OF TEMPERATURE AND DESICCA-TION ON THE PHOTOSYNTHETIC PERFOR-MANCE OF PORPHYRA PERFORATACabello-Pasini, A., Diaz-Martín, M. A., Muñiz-Salazar, R., Zertuche-Gonzalez, J. A., & Pacheco-Ruiz, I.Instituto de Investigaciones Oceanológicas, Univer-sidad Autónoma de Baja California, A.P. 453,Ensenada, Baja California 22800 Mexico

Porphyra perforata is a common seaweed inhabiting theupper intertidal zone, and as a consequence it experi-ences great fluctuations in tissue temperature anddesiccation. The objective of this work was to evaluatethe effect of ambient temperature and the tissue des-iccation status on the photosynthetic performance ofP. perforata. Photosynthetic performance was evalu-ated polarographically after the temperature or desic-cation treatments. Maximum photosynthesis (Pmax)occurred between 25 and 308 C and decreased athigher and lower temperatures, however, no signifi-cant differences were observed in the initial slope ofphotosynthesis (a) from 10 to 308 C. This suggeststhat the photosynthetic efficiency of this species doesnot decrease as a result of fluctuating temperaturesduring tidal emergence/submergence. Pmax and awere relatively constant in tissue of P. perforata with 5to 100% relative water content. This also suggests thatnatural desiccation rates during low tides do not de-crease photosynthetic rates in this species. Variationsin the synthesis of specific proteins as a result of fluc-tuations in temperature and relative water content inthe tissue of P. perforata are being studied.

29EFFECT OF LIGHT QUALITY ON POLYSAC-CHARIDE YIELD AND COMPOSITION OFTWO RED ALGAECarmona, R.1, Vergara, J. J.2, Lahaye, M.3 & Niell,F. X.41Department of Ecology and Evolutionary Biology, Uni-versity of Connecticut, One University Place, Stamford,CT 06901-2315, USA; 2Department of Ecology, Uni-versity of Cadiz, Poligono Rio San Pedro, 11510 Pu-erto Real, Cadiz, Spain; 3Institut National de la Re-cherche Agronomique, Unite de Recherche sur lesPolysaccharides, leurs Organisations et Interactions,BP 71627, 44316 Nantes, France; 4Department ofEcology, University of Malaga, Campus de Teatinos,Malaga 20971, Spain

Two species of agarophytes, Gelidium sesquipedale(Clem.) Born. et Thur. and Gracilaria tenuistipitata var.liui (Zhang & Xia), have been cultured in chemostatsystems under different light qualities to study the re-sponse of growth and polysaccharide yield and com-position to certain wavelengths. The yield of galac-tans, methoxyl groups and sulphate content in theagar as well as the starch concentration of these spe-cies are controlled by light quality in a different way,presumably because of their patterns of growth. Thepolysaccharide characteristics will be discussed in rela-tion to the growth and metabolism of those algae.

30DO PHYSICAL FACTORS REGULATE PHY-TOPLANKTON DISTRIBUTION PATTERNSIN LARGE, SHALLOW LAKES?Carrick, H. J.Watershed Research & Planning Department, SouthFlorida Water Management District, West Palm Beach,FL 33406 USA

Factors that regulate phytoplankton dynamics in shal-low, productive lakes are poorly understood, due totheir predisposition for frequent algal blooms andsediment resuspension events. In Lake Apopka, great-est phytoplankton biomass reflects wind-induced re-suspension of algae (meroplankton) that exists on theaphotic lake bottom in a layer approximately 5 cmthick; this assemblage is dominated by diatoms (.60%of total biomass) that can occur in resting stages.Once exposed to moderate light, meroplankton arecapable of growth and photosynthetic rates compara-ble with surface populations. In Lake Okeechobee, re-mote sensing was used to assess the basin-wide distri-bution of suspended particles. Satellite reflectancevalues agreed well with in situ particle densities at 20in-lake stations (average r2; LANDSAT 5 0.81,AVHRR 5 0.53), and maps of algal blooms (r2 5 0.79,p # 0.01). The greatest chlorophyll concentrations

PSA ABSTRACTS 11

occurred in the vicinity of tributary nutrient inputs atthe lake’s perimeter, while turbidity increased towardsthe center of the lake reflecting predominant watercirculation patterns. These results underscore the im-portance of physical-biological interactions in lakes.

31FRESHWATER DINOFLAGELLATES OF BEL-IZE, C.A.Carty, S.Department of Biology, Heidelberg College, Tiffin, OH44883 USA

Freshwater dinoflagellates have not previously beenreported from Belize, although there has been exten-sive work with marine dinoflagellates and some workwith other freshwater groups. Freshwater dinoflagel-lates are more frequently observed in standing waterand none have been observed in the several streamsand rivers sampled since 1990. The goal in 1998 wasto examine water samples from small ponds withinhours of collection to improve the chance of observ-ing swimming dinoflagellates. A plankton net wasused and whole water samples also were collected. Asmall brown water pond on a peninsula and 30m fromthe Caribbean yielded a bloom of Thompsodinium inter-medium. Dinoflagellates, including Peridinium centenni-ale, Katodinium sp., and Peridinium sp. in the Um-bonatum Group, were observed within “Crocodilepond” and “Lily pond” on the mainland.

32SOME PHYLOGENETIC RELATIONSHIPSWITHIN THE OSCILLATORIALES (CYANO-BACTERIA) CLADE USING 16S RDNA GENESEQUENCE DATACasamatta, D. A. & Vis, M. L.Department of Environmental & Plant Biology, OhioUniversity, Athens, OH 45701 USA

An approximately 1400 base pair region of the 16SrDNA gene was sequenced from taxa within the Oscil-latoriales in order to assess phylogenetic relationships.Ten previously unsequenced strains were obtainedfrom the University of Toronto Culture Collection.New sequence data were combined with previouslypublished sequences from a wide representation of cy-anobacteria including all currently available, com-plete Oscillatorialian taxa. Trees constructed usingparsimony, distance, and maximum likelihood meth-ods were similar in topology, although a few taxa werevariable in their placement depending on the phylo-genetic method employed. Newly sequenced taxa ofthe genera Phormidium, Oscillatoria, and Lyngbya didnot form monophyletic clades based on traditionalgeneric designations. Two Lyngbya strains (UTCC296and 313) and Phormidium subfuscum (UTCC474) formeda well supported monophyletic clade, but the affinity

of this clade with other groups was uncertain due tolack of bootstrap support. Oscillatoria sp. (UTCC393)was closely related to the previously sequenced Oscilla-toria limnetica and likewise, Phormidium molle(UTCC77) and Phormidium tenue (UTCC473) wereplaced in a well supported clade with other Oscillato-riales. The other four taxa were variously placed inthe trees and their phylogenetic positions could notbe determined with certainty.

33ULTRASTRUCTURE AND CYTOCHEMIS-TRY OF SPERMATANGIAL DEVELOPMENTAND FERTILIZATION IN AGLAOTHAMNIONOOSUMIENSE (CERAMIACEAE, RHODO-PHYTA)Chah, O. K.1, Lee, I. K.1 & Kim, G. H.21Department of Biology, Seoul National University, Seoul,151-732, Korea; 2Department of Biology, Kongju Na-tional University, Kongjushi, Chungnam 314-701, Korea

Spermatial development and fertilization processeswere investigated by electron microscopy in Ag-laothamnion oosumiense Itono. The spermatium is com-posed of two parts, an ovoidal head and two append-ages projecting from each distal end. The appendagesoriginate from spermatangial vesicles (SVs) and fol-low a developmental sequence beginning as amor-phous material and ending as a fully-formed fibrousstructure compressed within the SVs. SV formation isdue to contributions initially from endoplasmic retic-ulum and later from dictyosome-derived vesicles.Chemical differentiation of the spermatial wall occursearly in its development. Calcofluor white does not la-bel spermatial walls, indicating an absence of cellu-lose polysaccharides, which are abundant in vegeta-tive cell walls. Liberated spermatia had a prophasearrested nucleus with a pair of polar rings. The cyto-plasm of the trichogyne was connected with that ofspermatia at the fertilization canal. The cytoplasm ofthe trichogyne was empty when the nuclear fusion be-tween spermatium and carpogonium occurred.

34COMPARISON OF GROWTH AND REPRO-DUCTION BETWEEN TWO POPULATIONSOF SARGASSUM SILIQUASTRUM IN PINGCHAU, HONG KONGChan, W. Y. & Ang, P. O.Department of Biology, The Chinese University of HongKong, Shatin, N.T., Hong Kong SAR, China

In Ping Chau Island of Hong Kong, two populationsof Sargassum siliquastrum are present. One is in theshallow water of about 1 to 3 m Chart Datum (CD),and the other one in deeper water of 5 to 10 m CD.These two populations are separated by an extensive

12 PSA ABSTRACTS

sand patch. Individuals of the “shallow” water popula-tion increased their size from a mean length of 8.3 63.6 (SD) cm in Aug 1998 to a maximum of 48.2 629.9 cm in early Jan 1999 before they started to dieback. In the following year, they attained a minimumof 6.1 6 3.8 cm in May 1999 and a maximum of 56.1 623.6 cm in Dec 1999. Their reproductive period lastedfor two to three months from Jan to Feb 1999, andagain from Nov 1999 to Jan 2000. The “deep” waterindividuals increased their size to a maximum of 123 650.8 cm at the end of Jan 1999 and started to die backin Feb, 1999. They again reached their maximummean length in Jan 2000. Their reproductive periodlasted for five to six months from Sept 1998 to Feb1999 and again from Sept 1999 to Jan 2000. The“deep” water individuals tended to be longer in sizeand they attained their maximum growth a monthlater than the “shallow” water individuals. Their re-productive season tended to start earlier and lastedlonger than those in the “shallow” water. These differ-ences in the phenology of the two populations may berelated to the temperature differences (up to 58 C dif-ference in summer) between the two depths. Sargas-sum siliquastrum is likely to be a cold adapted speciessuch that warmer temperature in the shallow waterhas compressed and shortened their rapid growthand reproductive period to within the few coldermonths in fall and winter.

35SEXUAL REPRODUCTION AND GENETICVARIATION IN THE SUBAERIAL ALGACEPHALEUROS VIRESCENS (ULVOPHYCEAE,CHLOROPHYTA)Chapman, R. L.1, Waters, D. A.1, & Lopez-Bautista, J. M.21Department of Biological Sciences, Louisiana StateUniversity, Baton Rouge, LA 70803 USA; 2Departmentof Biology, University of Louisiana at Lafayette, Lafay-ette, LA 70504 USA

Cephaleuros virescens is a pantropical subaerial greenalga with no known long-range dispersal mechanisms.Sexual reproduction is relatively rare and may involveintragametangial fusion of identical, mitotically pro-duced gametes. This situation may be a consequenceof adaptation to the subaerial habitat. Genetic varia-tion among populations of C. virescens may be very lowand might be positively correlated to the distance(hence, time) separating populations. Thus, assessingthe global biogeography of C. virescens requires analy-sis of what might be low levels of variation. Because C.virescens occurs on literally hundreds of different hostspecies, the question of host-races must also be consid-ered. Preliminary analysis of local populations of C. vire-scens, originally obtained as field collections from threedifferent host species and subsequently raised in cul-ture, is the first step in addressing the biogeography

of this alga. We are using the AFLP plant mappingprotocol by PE Applied Biosystems to detect geneticvariability in the three isolates of C. virescens. AFLP is aPCR-based DNA fingerprinting technique that detectsthe presence or absence of restriction fragmentsrather than fragment length differences. Because thenumber of restriction fragments that can be detectedwith the AFLP technique is “virtually unlimited,” it is avery powerful tool for assessing the degree of related-ness or variability among cultivars or isolates. AFLPtechniques have been used successfully to distinguishmorphologically identical bacteria, determine relat-edness among soybean accessions, reveal genetic vari-ability within bee samples, and identifyfall armywormstrains and hybrids.

36COLD ACCLIMATION OF TWO STRAINS OFTHE CYANOBACTERIUM, SPIRULINA PLAT-ENSISChien, L.-F. & Vonshak, A.Microalgal Biotechnology Laboratory, The JacobBlaustein Institute for Desert Research, Ben-GurionUniversity of Negev, Sede-Boker Campus, 84990, Israel

The changes in the antioxidant enzymes and photo-synthetic activities during cold acclimation in twostrains of the cyanobacterium, Spirulina platensis,marked as Kenya and M2, were investigated. Cellswere cultured at 338 C then transferred to either 208 Cor 158 C. Growth rate of both strains ceased when thetemperature shifted from 33 to 208 C and resumed toa slower rate after the first 24 h. Similarly when thetemperature was shifted from 33 to 158 C, a completecessation of growth took place but this time thegrowth resumed only after 5 to 6 days. The activities ofascorbate perooxidaseperoxides were immediately de-creased to about 40–60% in Kenya and 20–40% in M2when the temperature was shifted to 20 or 158 C andremained about the same level during further coldcultivation. The activity of glutathione reductase wasnot modified immediately after the transfer to 20 or158 C; however, it trended to increase gradually in M2during cultivation at 158 C. The changes in the maxi-mal efficiency of PSII photochemistry (Fv/Fm) werefollowed in order to study the effect of low tempera-ture acclimation on the photosynthetic apparatus ofthe two strains.

37ATLANTIC KELP SPECIES LAMINARIA LONGI-CRURIS AND L. SACCHARINA (LAMINARI-ALES) ARE CONSPECIFICCho, G. Y.1, Yoon, H. S.1, Boo, S. M.1, & Yarish, C.21Department of Biology, Chungnam National Univer-sity, Daejon, 305-764, Korea; 2Department of Ecologyand Evolutionary Biology, University of Connecticut,Stamford, CT 06903 USA

PSA ABSTRACTS 13

The identification of two Atlantic kelp species, Lami-naria longicruris and L. saccharina, has been controver-sial. In order to know if these two species are conspe-cific, plastid-encoded RuBisCo spacer and nuclearrDNA ITS sequences were analyzed from twelve indi-viduals of L. longicruris, five of L. saccharina, from Con-necticut and Nova Scotia. Four individuals of L. digi-tata from the above coasts were also analyzed asreference in this study. All RuBisCo spacer sequencesfrom L. longicruris and L. saccharina were exactly iden-tical except for one individual with three different nu-cleotides. Zero to five different nucleotides of ITS se-quences, inculding four polymorphic sites, werefound in two species. However, their RuBisCo spacerand ITS sequences are quite different from those of L.digitata. These results strongly suggest that L. saccha-rina (L.) Lamour. 1813 is conspecific with L. longicru-ris De La Pylaie 1824 and the different local popula-tions, despite various morphotypes, may be geneticallyvery similar.

38TAXONOMY OF CERAMIUM (CERAMI-ACEAE, RHODOPHYTA) FROM OREGONCho, T. O.1, Boo, S. M.1, & Hansen, G.21Department of Biology, Chungnam National Univer-sity, Daejon 305-764, Korea; 2Hatfield Marine ScienceCenter, Oregon State University, Oregon, U S A.

During a recent survey of marine red algae in Ore-gon, U. S. A., 6 of the 7 species of Ceramium reportedfrom this state were collected in the intertidal zone.These included Ceramium californicum J. Agardh, C. ci-mbricum H. Petersen in Rosenvinge, C. codicola J.Agardh, C. gardneri Kylin, C. kondoi Yendo, and C. paci-ficum (Collins) Kylin. Detailed descriptions and illus-trations of vegetative and reproductive developmentin C. californicum, C. codicola, and C. pacificum are pre-sented for the first time in this paper. Descriptions arealso given for C. cimbricum and C. kondoi, species previ-ously only reported from elsewhere in the northwest-ern Pacific. These latter species were common onfloating docks, sites where introduced species fre-quently occur. Ceramium eatonianum and C. washing-toniensis, the other 2 species known from Oregon,were found to belong to other genera or were not col-lected during this study.

39POLYPHOSPHATE AND SILICEOUS GRAN-ULES IN THE GAMETOPHYTES OF THE REDALGA PORPHYRA PURPUREA (BANGIO-PHYCEAE)Chopin, T.1, Morais, T.1, Belyea, E.1, & Belfry, S.21University of New Brunswick, Centre for Coastal Stud-ies and Aquaculture, P.O. Box 5050, Saint John, NB,

E2L 4L5, Canada; 2University of New Brunswicc,Electron Microscopy Unit, Bag Service 45111, Frederic-ton, NB, E3B 6E1, Canada

Variations of the different phosphorylated fractions intissues of starved and fresh plants of Porphyra purpurea,a representative of the Bangiophyceae, over a 72 hourincubation period in pulse-enriched seawater (15 mMphosphorus and 25 mM nitrogen) were analyzed andcompared to those in Chondrus crispus, a representa-tive of the Florideophyceae, considered the more ad-vanced of the two classes of the Rhodophyta. Differ-ences point towards P. purpurea being a much moremetabolically active phosphorus “pump” than C. cris-pus, with a higher phosphorus turnover rate, in whichthe orthophosphate fraction is predominant and acid-soluble and acid-insoluble polyphosphates are not assignificant storage pools. Confirmation of the pres-ence of acid-insoluble polyphosphates, detected bychemical analyses, in the form of cytoplasmic granuleswas obtained by transmission electron microscopyand energy dispersive X-ray microanalysis. The gran-ules in P. purpurea were, however, much smaller (20 to110 nm in diameter) than those in C. crispus (around1 mm, but some larger than 2 mm in diameter).Larger granules (290 to 310 nm in diameter) werealso observed. Their surface was more uniformly elec-tron-opaque without the reticulated or globular ap-pearance of typical polyphosphate granules. Energydispersive X-ray microanalysis demonstrated that theywere siliceous granules. To our knowledge, this is thefirst report in algae of such structures whose occur-rence and metabolic role remain enigmatic.

40MOLECULAR AND GENETIC ANALYSIS OF ARETROGRADE SIGNALING PATHWAY FROMTHE PLASTID TO THE NUCLEUSChory, J.1, Larkin, R. 1, Surpin, M.1; Mochizuki,N.2, & Brusslan, J.31Howard Hughes Medical Institute & The Salk Insti-tute for Biological Studies, La Jolla, CA 92037 USA;2Kyoto University, Kyoto, 606-8502 JAPAN;3California State University, Long Beach, CA 90840USA

Chloroplast development requires coordinate nuclearand chloroplast gene expression. A putative signal fromthe chloroplast couples the transcription of certainnuclear genes encoding photosynthesis-related pro-teins with chloroplast function. We have identifiedfive Arabidopsis nuclear genes (GUN1-GUN5) necessaryfor coupling the expression of some nuclear genes tothe functional state of the chloroplast. Homozygousrecessive gun mutations allow nuclear gene expres-sion in the absence of chloroplast development.GUN1 mutants have no visible phenotype in white

14 PSA ABSTRACTS

light, but GUN1 mutations interfere with the switchfrom heterotrophic to photosynthetic growth in youngseedlings. GUN2-5 are pale. Double mutant studiessuggest that gun1 affects a separate pathway fromGUN2, 3, 4, and 5. GUN2 and GUN3 are allelic to theknown photomorphogenetic mutants, hy1 and hy2,involved in phytochromobilin biosynthesis down-stream from heme. GUN5 encodes the ChlH subunitof Mg-chelatase, and GUN4 encodes a novel chloro-plast protein that is essential for chlorophyll accumu-lation. GUN4 does not appear to be required for thesynthesis of protochlorophyllide from 5-aminole-vulinic acid, which suggests that GUN4 might be re-quired for the early steps and/or the late steps ofchlorophyll synthesis or another process that is re-quired for chlorophyll accumulation. Our data sug-gest that certain perturbations of the tetrapyrrole bio-synthetic pathway generate a signal from chloroplaststhat causes transcriptional repression of nucleargenes encoding plastid-localized proteins. The pre-cise nature of this signal and the mechanism by whichthis signal is transduced to the nucleus is under inves-tigation.

41BUILDING A SPECIES PHYLOGENY FORTHE GENUS COLEOCHAETE (COLEOCHA-ETALES) USING THE GENES RBCL AND ATPBCimino, M. T. & Delwiche, C. F.Department of Cell Biology and Molecular Genetics,University of Maryland - College Park, College Park,MD 20742 USA

The freshwater green alga Coleochaete Breb. (Co-leochaetaceae; Coleochaetales) is a key streptophytegenus and is important to the understanding of theevolutionary origin of embryophytes (land plants). Todate only a few species have been available from pub-lic culture collections. To facilitate research on thisgenus we have isolated 17 previously uncultured spe-cies of Coloechaete from material collected in theUnited States, Puerto Rico, and the Dominican Re-public. Sequences for the genes rbcL and atpB weredetermined for these new isolates of Coleochaete (andfor existing cultures) and combined with sequencesfrom representative other streptophytes. Phylogeneticanalyses indicate that Coleochaete, along with Chaeto-sphaeridium and Chara, are closely related to embryo-phytes and constitute a ‘higher streptophyte’ clade. Atleast four well-supported lineages exist within Co-leochaete. Characteristic growth forms have been iden-tified for these four lineages, with important charac-ters including aspects of thallus establishment, thallushabit, zygote development and hair sheath position.These data provide an improved understanding ofspecies diversity and character evolution in the genusColeochaete, and facilitate examination of hypothesesconcerning character evolution in the streptophytes.

42PHYLOGENETIC RELATIONSHIP OF COLEO-CHAETE AND CHAETO-SPHAERIDIUM (COLEO-CHAETALES) BASED ON THE CHLOROPLASTGENES RBCL AND ATPBCimino, M. T., Karol, K. G., Lewandowski, J. D.,& Delwiche, C. F.Department of Cell Biology and Molecular Genetics,University of Maryland - College Park, College Park,MD 20742 USA

The freshwater green algal genera Coleochaete and Cha-etosphaeridium form the order Coleochaetales sensuMattox and Stewart (Charophyceae). To test themonophyly of this order, a data set was compiled con-sisting of the chloroplast genes rbcL and atpB fromnine species of Coleochaete, six strains of Chaetosphaerid-ium, and other representative green algae and em-bryophytes. Phylogenetic analyses of these data indi-cate that Coleochaete and Chaetosphaeridium form amonophyletic group that diverged late in basal strep-tophyte evolution. By contrast, published analyses ofnuclear encoded small subunit ribosomal DNA(rDNA) data for similar taxa do not support a mono-phyletic Coleochaetales. These analyses suggest Cha-etosphaeridium is an early branching lineage withinStreptophyta and/or that Chaetosphaeridium forms alineage with the unicellular flagellate Mesostigma (Me-sostigmatophyceae). A close relationship of Chaeto-sphaeridium and Mesostigma is not supported by therbcL and atpB data. Reexamination of morphologicalcharacters suggests a monophyletic Coleochaetales issupported by several characters that include branch-ing filamentous habit, unicellular apical growth,sheathed hairs, and rotating plastids.

43HABITAT HETEROGENITY ON TROPICALROCKY SHORES: A SEAWEED STUDY INSOUTHERN BRAZILCoimbra, C. S.1,2 & Berchez, F. A. S.21Departament of Biological Sciences, Universidade Es-tadual de Santa Cruz, Rod. Ilhéus/Itabuna, Km. 16,Bahia, Brazil; 2Departament of Botany, Biosciences In-stitute, Universidade de São Paulo, Caixa Postal11461 SP-Brazil

The main concepts in coastal community ecologyhave been proposed to explain relatively plain sub-strate, specially at temperate zones. We show that, ona irregular tropical substratum (a complex system ofquarry stones with diverse shapes and sizes), the classi-cal community zonation scheme is only applicable ifwe simplify the tridimensional substrate arrangementto a single dimensioned universe: the topographiclevel. Thus, the continuous spatial distribution implic-

PSA ABSTRACTS 15

ited in “zones” notions is nonexistent. Our study wasconducted on a rocky shore at Ubatuba (São PauloState, Brazil) during one year. Percentual coveragewas estimated using the quadrat method located byrandom coordinates. The topographic level was deter-mined for each sampling element. Analysis of spatialsplitting revealed large-scale stratification of the shoreinto dominiums related to topographical level: 1) Up-per Dominium (represented by Chthamalus sp. andTetraclita spalactifera); 2) Transition Level (composedof Gymnogongrus griffithsiae, Gelidium aff. pusillum andoften Centroceras clavulatum);. and 3) Lower Domin-ium (mainly Sargassum vulgare and occasionally Padinagymnospora, Dictyopteris delicatula and Grateloupia dory-phora). These dominiums cannot be recognized as“bands” or continuous “zones” in a landscape view ofthe community. Otherwise, these bands could be ob-served on a small scale on each large quarry stone.

44TUBE SIZE COMPARISON AND AUTO-MATED GROWTH MEASUREMENT IN ATUBULAR REACTOR USING SPIRULINAPLANTENSISCoin, M. A., Bagherpour, S. & Gellenbeck, K. W.Rehnborg Center for Nutrition & Wellness, NutriliteDivision of Amway Corporation, 19600 6th Street,Lakeview, CA 92567 USA

A tubular photobioreactor for outdoor cultivation ofSpirulina platensis was successfully operated for the lasttwo years. The reactor was made of transparent 2.4-cmdiameter tubes with a total length of approximately101-m and a volume of 124-liter. Flow was induced us-ing an airlift pumping system. To optimize the systemfurther, a larger tube diameter was also tested. Prelim-inary results have suggested that a larger tube diame-ter might provide increased output with reducedsurface area requirements. Results of experimentscomparing the productivity of the same culture vol-ume in tubes of 2.4 cm and 5.0 cm will be presentedwhich show a small decrease in productivity by vol-ume, but a large increase in areal productivity. Thissuggests that the larger tube diameter would be an ap-propriate choice for larger scale systems. Additionally,data will be presented demonstrating the effectivenessof an on-line surface scatter turbidimeter for accuratemeasurement of Spirulina density when correlated tomanual dry weight measurements.

45THE FISH POND EXPERIMENT: CHAPTERTWOColeman, A. W.BioMed, Brown University, Providence, RI 02912USA

Forty years ago, after 1 1/2 years of weekly surveys, aBaltimore fishpond was inoculated with three identifi-able clones of Pandorina morum. The results of subse-quent recollection attempts are published in Amer.Naturalist 118:761 (1981). More recently, molecularanalyses have permitted characterization of the P.morum population that was endemic to the pond. Theresults, and their comparison with those from other P.morum sites, challenge some longstanding assump-tions concerning the importance of various lifehistorystages to the introduction and maintenance of algalpopulations in temperate freshwater locales.

46INFECTIOUS DISEASES IN MACRO-ALGAE:THE EFFECT ON HOST FITNESSCorrea, J. A., Faugeron, S., Martínez, E.,Nimptsch, J. & Paredes, A.Departamento de Ecología, Facultad de Ciencias Bio-lógicas, P. Universidad Católica de Chile, Casilla 114-D, Santiago, Chile

The understanding of infectious diseases of algae hasimproved significantly in recent years, particularly inthe area of recognition and signaling, key processesthat determine the success or failure of host invasionby the pathogen. Ecological studies have also contrib-uted to better understanding the role of diseases inwild stands of the affected hosts. An aspect that has re-ceived only limited attention is the effect of the infec-tions on host fitness, and in this context, we report afirst attempt to quantifying the effects of Pleurocapsasp. (Cyanophyta) on the reproductive potential of itshost Mazzaella laminarioides (Rhodophyta). Infectionsby Pleurocapsa trigger the development of tumors thatcan result in major changes in frond morphology andtexture. Two populations of the host were consideredin the study. Our results indicate that infections donot cause a significant effect on the density or qualityof the reproductive structures (i.e. cystocarps and tet-rasporangia). However, the number of spores, settle-ment rates, germination success and offspring sur-vival, were all affected negatively by the endophyticinfections. The reported information and field-col-lected data, strengthen the notion that pathogens ofalgae may exert strong effects on their hosts at severallevels, including reproduction. These effects can varyfrom host death during infections by highly patho-genic organisms to more subtle effects like those ob-served in the studied pathosystem. Infections by lessaggressive pathogens, however, still may determineimportant effects at the population level by inducingdifferential mortality and reproductive success in in-fected individuals.

16 PSA ABSTRACTS

47THE IMPACT OF DIFFERENTIAL GRAZINGBY PHAGOTROPHIC CILIATES ON PHY-TOPLANKTON BIOMASS AND COMMUNITYSTRUCTURECowlishaw, R. J.Oregon Institute of Marine Biology, University of Ore-gon, Charleston, OR 97420 USA

There is a growing understanding that phagotrophicciliates are often important members of aquatic com-munities in terms of their trophic role and mobiliza-tion of small cell production to higher consumers. Asformidable consumers of small phytoplankton speciesthey are likely to be also important in determining thecommunity composition of the pico- and nanophy-toplankton assemblages. Dilution method experi-ments were conducted during the winter and summerin the South Slough, an arm of the Coos Bay on thesouthern Oregon coast, to assess the impact of ciliategrazing on two size fractions of chlorophyll (0.2 to 5mm and .5 mm) and on the growth and abundanceof specific phytoplankton groups, particularly crypto-phytes and Synechococcus sp. The premise of the dilu-tion technique is that grazers are diluted with theirfood and the observed rate of change in chlorophyllor phytoplankton abundance is linearly related to thedilution factor. Results from previous studies usingthe dilution technique have been given in terms ofthe grazing impact of microzooplankton on totalchlorophyll. The findings of the research presentedusing a more rigorous application of the dilutionmethod suggest that ciliates are differential in theirgrazing of phytoplankton, targeting small phytoplank-ton biomass and preying selectively on components ofthe assemblage that constitute this biomass.

48REACTIVE OXYGEN METABOLISM IN THETROPICAL BROWN ALGA DICTYOTADICHOTOMADavison, I. R.1, Collén, J.2 & Fegley, J. C.11School of Marine Sciences and Department of Biologi-cal Sciences, University of Maine, Orono, ME 04469USA; 2Department of Physiological Botany, UppsalaUniversity, Villavägen 6, S-752 36 Sweden

We studied reactive oxygen metabolism in naturalpopulations of the brown alga Dictyota dichotoma grow-ing on coral reefs on the west coast of Barbados inMarch 2000. Algae from deep water (27 to 30 m) hadlower dark respiration (0.08 cf. 0.21 mmole O2 cm22

h21), light compensation point (7 cf. 18 mmole pho-tons m22 s21) and gross light-saturated photosynthesis(0.44 cf. 0.68 mmole O2 cm22 h21) than the same spe-

cies from shallow (2 to 3 m) water. Compared to shal-low water algae, those from 27 to 30 m were more sus-ceptible to photoinhibition, produced more reactiveoxygen (as measured by dichlorofluorescein produc-tion) and suffered lipid peroxidation when exposedto surface solar radiation. These data could not be ex-plained by differences in activities of reactive oxygenprocessing enzymes. Although activities of ascorbateperoxidase (APX) were higher in shallow water algae,the opposite was true for superoxide dismutase (SOD)and catalase. In situ reactive oxygen production inshallow water D. dichotoma varied over the course ofthe day on both a sunny and overcast day, and wasproportional to incident light and photosyntheticelectron turnover rate (ETR) determined with a sub-mersible modulated fluorometer. The natural popula-tion did not appear to experience lipid peroxidation.Activities of SOD and APX remained constant overthe light period, whereas catalase declined in the af-ternoon on the sunny day, but not on the overcastday. Overall, our data demonstrate that algae producereactive oxygen in nature under non-stressed condi-tions and moderate light (, 300 mmole photons m22

s21) and that this occurs independently of the activityof catalase.

49KELP ECOLOGY AND THE POINT LOMAKELP FOREST: A BLEND OF THE OLD ANDTHE NEWDayton, P. K. & Tegner, M. J.Mail Code 0227, Scripps Institution of Oceanography,La Jolla, CA 92093 USA

The history of the Point Loma kelp forest parallelsthat of the earlier pioneers in Europe, with an earlydescriptive focus moving quickly toward mechanisticstudies. At Point Loma, research was initiated becauseof large-scale loss of kelps, so from the beginningthere was an urgency to restore the kelp forest with aconcomitant focus on sea urchin grazing. We reviewthe evolving relationships between new questions andlong-term observations that emphasize both small andlarge-scale events in time and space. For example, theearly descriptive work grew into small-scale experi-mental work that demonstrated problems of scalingup from experiments. As we repeated experimentsover larger spatial and temporal scales we learned thatthe low frequency variation at both scales is extremelyimportant and must be understood before small-scaleresults are generalized. Regime shifts in the physicalenvironment and the increasing effects of fishing rep-resent continuing challenges to the kelp communitystructure that make it critically important to considerscaling problems.

PSA ABSTRACTS 17

50GROWTH AND ULTRASTRUCTURAL CHAN-GES IN DICTYOSPHAERIUM PULCHELLUMEXPOSED TO COPPER (CHLOROCOC-CALES, CHLOROPHYCEAE)de la Peña, G.1, Andrade, L. R.1, Amado Filho, G.M.1 & Rodríguez, M. C.21Lab. de Biomineralizacao, Instituto de Ciencias Bio-medicas, CCS, UFRJ, Brasil; 2Departamento de Cien-cias Biológicas, Facultad de Ciencias Exactas y Natu-rales, Universidad de Buenos Aires, 1428 BuenosAires, Argentina

In an assay addressing the toxicity of copper to Dicty-osphaerium pulchellum, a 48 hours’ exposure of axeniccultures of the alga to metal concentrations rangingfrom 0 to 300 mg L21 caused a significant decrease inthe growth rate and cell chlorophyll content. Extra-cellular mucilage remotion by controlled sonicationbefore exposure to copper emphasized chlorophyllcontent reduction, but not cellular density diminu-tion. Because mucilage acts as a cation interchanger,these results suggested that, during at least the first 48hours, division rates might be affected by lower Cu12

concentrations than chlorophyll content. Ultrastruc-tural observations showed that the normal organiza-tion of the chloroplasts was altered; they presented di-lated lamellae, irregularly arranged with practicallyno stacking. Copper precipitates were mainly ob-served outside the plasmalemma or within the extra-cellular mucilage. Electron probe microanalysis con-firmed these observations, showing only minorprecipitates inside the cells.

51TEMPORAL AND SPATIAL PRODUCTION OFAGGLUTININS IN MARINE MACROALGAEFROM THE MEXICAN CARIBBEANDe Lara-Isassi, G., Álvarez-Hernández, S.,Lozano-Ramírez, C., Hernández-Soto, N. &Dreckmann, K. M.Departamento de Hidrobiología. División de CienciasBiológicas y de la Salud. Universidad Autónoma Met-ropolitana-Iztapalapa. Apartado Postal 55-535, D. F.09340, México

The presence or absence of secondary metabolites inalgae has been long discussed. There are several hy-potheses to explain the synthesis of secondary metab-olites in algae as a response to herbivory pressure,competence or predation. In this work we made ascreening test of chlorophyte and rhodophyte speciescollected in different sites of the Caribbean sea in or-der to test them for agglutinins. The extracts wereprepared in a phosphate buffer solution 100-mM, pH7.2 and filtered using 0.22 mm Millipore filters. Agglu-tination tests were done in microtiter-plates using for-

malinized rabbit and human A, O, B erythrocytes. Ag-glutination titer was recorded and expressed as thereciprocal of the highest dilution showing positive re-sults. A total of 31 samples were analyzed; seven Chlo-rophyta species and 11 Rhodophyta showed aggluti-nating activity. The species that showed activity variationincluded the chlorophytes, Caulerpa cupressoides, Caul-erpa paspaloides, Halimeda opuntia and Penicillus capita-tus and the rhodophytes, Chondria litoralis, Digenea sim-plex, Gracilaria cornea and Laurencia obtusa. Theagglutinating activity of Liagora farinosa is reported forthe first time. This research indicates that ecologicalpressures are an important factor in seaweeds aggluti-nins synthesis.

52GRAPPLING WITH CONFLICT AMONGINFORMATION SOURCES IN RECON-STRUCTION OF THE EARLY EVOLUTIONOF LAND PLANTSDelwiche, C. F.1, Karol, K. G.1, Cimino, M. T.1, &McCourt, R. M.21Department of Cell Biology and Molecular Genetics,H.J. Patterson Hall, University of Maryland - CollegePark, College Park MD 20742-5815; 2Department ofBotany, Academy of Natural Sciences, 1900 BenjaminFranklin Parkway, Philadelphia PA 19103 USA

Although a close relationship between embryophytes(land plants) and charophycean green algae has beendiscussed for over a hundred years, the precise natureof this relationship remains uncertain. This is largelybecause of difficulty reconstructing the phylogeny ofthe basal members of this group. Recent analyses ofSSU rDNA, rbcL, and concatenated chloroplast geneshave all produced different phylogenies, and none isfully compatible with morphological data. Noteworthyconflict is apparent in the positions of the unicellularflagellate Mesostigma and the filamentous epiphyteChaetosphaeridium. Several phenomena could result insuch incongruence, including problems with the un-derlying data (taxon ID, sequence determination,alignment, etc.), choice of analytical method, lack ofresolution with one or more of the datasets, unrecog-nized paralogy, and horizontal gene transfer. We haveexamined each of these possible sources of incongru-ence, and have determined that several factors under-lie the apparent conflict among phylogenies. Whenthese factors are taken into account a consensus mo-lecular phylogeny begins to emerge. Despite the longdivergence time in question, the prospects for recon-struction of land plant phylogeny are good.

53EFFECT OF NITROGEN ADDITION ON AMIXED SPECIES PHYTOPLANKTON BLOOMDeYoe, H.1, Buskey, E.2, Jochem, F.2, andVillareal, T.2

18 PSA ABSTRACTS

1Biology Department, the University of Texas - PanAmerican, 1201 W. University Dr., Edinburg, TX78539 USA; 2Marine Science Institute, The Universityof Texas at Austin, 750 Channelview Dr., Port Aran-sas, TX 78373 USA

The Laguna Madre of Texas is a hypersaline lagoonthat in recent years has been dominated by the browntide alga, Aureoumbra lagunensis although a Synechococ-cus-like sub-dominant is typically present. Dominanceof A. lagunensis is thought to be due at least in part toits nitrogen competitive abilities. A mesocosm studywas performed to determine if an increase in ambientnitrogen concentration would lead to a shift in thedominant alga. Twelve fiberglass cylinders enclosing1.2 cubic meters of Laguna Madre water were de-ployed for 16 days. Four times during this period, am-monium was added (N1 mesocosms) to half the me-socosms to achieve a post-addition concentration ofapproximately 40 mM. The average initial particulateN/P ratio was 40/1 (SD 5 2.9) which recent evidenceindicates is within the range of N/P ratios for N-lim-ited A. lagunensis. In control mesocosms, total cell bio-volume (TCB) of A. lagunensis cells dropped after 4days by a factor of four and then increased to a levelslightly above the day 0 value by day 16. In N1 meso-cosms, A. lagunensis TCB was unchanged after 4 daysthen doubled by day 16. Despite the differences in fi-nal yield, growth rates of A. lagunensis in the two treat-ments were similar. The Synechococcus-like organism,showed a four-day lag before TCB in both treatmentsincreased although at a slower rate in the control me-socosms. By the end of the experiment, TCB of A. la-gunensis was two to six-times greater than that of sub-dominant. Despite the nitrogen treatment, A.lagunensis retained dominance.

54PHYTOPLANKTON COMMUNITY STRUC-TURE: TEMPORAL VARIABILITY IN A TROP-ICAL UPWELLING ECOSYSTEMDíaz-Ramos, J. R.1, 2, Muller-Karger, F. E.2, Millie,D.3, Troccoli-Ghinaglia, L. E.4, Subero-Pino, S.S.5, & Varela, R.61Dpto. Biología Marina, Instituto Oceanográfico deVenezuela, Cumaná Sucre, Venezuela; 2Dpt. MarineScience, University of South Florida, St. Petersburg, Fl,33701 U.S.A.; 3U. S. Department of Agriculture, c/oMote Marine Laboratory, Sarasota, Fl, 34236 U.S.A;4Dpto. de Acuicultura, Universidad de Oriente, Bocade Río, Nva. Esparta, Venezuela; 5Dpto. de Biología,Universidad de Oriente, Cumaná, Sucre, Venezuela;6Fundación La Salle, Punta de Piedras, Nva. Esparta,Venezuela

The Cariaco Basin (Southeastern Caribbean Sea) isthe largest anoxic basin of oceanic character. Its sur-

face waters are affected by coastal upwelling duringboreal winter and spring. Historical information onthe phytoplankton communities in the basin is scarce.In November 1995, an oceanographic time-series sta-tion was established at 10.58N - 64.668W. In this studychanges in the structure of the phytoplankton com-munity in the upper 100-m layer were studied.Monthly samples to determine phytoplankton abun-dance and pigment composition (HPLC) were col-lected from November 1995 to January 1999; watertemperature was used as proxy for upwelling. Surfacewaters reached temperatures #248 C during the up-welling season, and surpassed 268 C during the rest ofthe year. A total of 300 species were found. Generally,the highest number of cells (.500 cells ml21) weremeasured from January to April every year. Diatomswere the dominant group in terms of abundance, spe-cies composition (168 species) and pigments (Chl cand fucoxanthin) during this period. The abundanceand marker pigment concentration (peridinin, but-and hex-fucoxanthin) for other groups support thisobservation. During the rest of the year diatom andtotal abundance decreased markedly (,100 cellsml21). Small organisms (,5 mm) became dominant.The maximum concentration values of zeaxanthinand But- and Hex-Fuco in this period indicated thepresence of cyanobacteria and prymnesiophytes. Thesparse and relatively low concentration of Chl b, luteinand prasinoxanthin indicated that chlorophytes andits allies are a minor floral component.

55ADVANCES IN A MONOGRAPH OF THEGENUS GRACILARIA (RHODOPHYTA) INTHE MEXICAN ATLANTICDreckmann, K. M., De Lara-Isassi, G. & Alvarez-Hernández, S.Departamento de Hidrobiología, División de CienciasBiológicas y de la Salud, Universidad Autónoma Met-ropolitana-Iztapalapa, Apartado postal 55-535. D. F.09340 México

Some species of the genus Gracilaria Greville(Gracilariales, Rhodophyta) are the main source ofagar. For that reason, the taxonomic study of thetaxon has become relevant for many scholars. In or-der to bring the Mexican floristics knowledge of thegenus into the state-of-the-art about it, we have initi-ated the needed monography. The character defini-tion has proved to be the most important task. Wehave found that the most reliable characters for thespecies delimitation are: general form of the thallus,length and width; form of the axes, length and width;branching pattern; number of axes from the holdfast;form of the holdfast; presence of constrictions at thebase of the branches or not; color; length of the seg-ments; consistency; form of the apices; length andthickness of the stipes; surface texture of the

PSA ABSTRACTS 19

branches, smooth, crispidous, etc; adherency to her-barium paper; cellular forms of the transition fromcortex to medulla, size and thickness of celular wallsof the cells involved; number of celular layers of thecortex, subcortex (if present) and medulla; form,number and distribution of the spermatangial con-ceptacles; form and size of the cystocarps, if con-stricted at the base or sessile; diameter of the ostioleand if it is apiculated or not; disposition of the car-posporangial chains; form of the gonimoblastic cells,and form and number of tetrasporangia. A diagra-matic description for each is provided.

56PHYLOGENETIC SELECTION OF A RE-SOURCE: A NEW USE FOR CLADISTICSDreckmann, K. M., De Lara-Isassi, G. & Alvarez-Hernández, S.Departamento de Hidrobiología, División de CienciasBiológicas y de la Salud, Universidad Autónoma Met-ropolitana-Iztapalapa, Apartado Postal 55-535, D. F.,09340, México

A phylogenetic model for the selection of commercialresources using the cladistic method is proposed. Thegroup selected as an example was the marine agaro-phyte red algal genus Gracilaria Greville. We suggestthe use of the cladistic principle of evolutionary trans-formational series in order to test the quality of agarsinstead of the assay-herror traditional method thatconsumes time and budget. If we asume that the“good quality of agar” in extant taxa is a sinapomor-phic character (but not a reliable taxonomic one),then taxa included in the same monophiletic clade inwhich the species with “good quality of agar” are, hasa high evolutionary posibility to share that character.In order to do this we have to incorporate to the set ofavailable specific characters, those of the taxa actuallyused as a agar source but not present in the area un-der scope. A complete set of the basic cladistic data re-quired for run the most popular program currently inuse (PAUP) are provided. We applied the model tothe Mexican Atlantic species and found that, usingGracilaria chilensis and G. cornea as “indicator taxa,”and found Mexican populations of G. crassissima, G.caudata, G. cervicornis and Gracilariopsis lemaneiformisare candidates for a study of yield and agar properties.

57POTENTIAL TOOLS FOR TRACKINGOCEAN CLIMATE: VARIABILITY IN STABLEISOTOPES IN LIVING CORALLINE ALGAEDunn, R. A.1, Steller, D. L.1, & Zachos, J.21Biology Dept., UC Santa Cruz, Earth and Marine Sci-ences Bldg., Santa Cruz 95064 USA; 2Earth SciencesDept., UC Santa Cruz, Earth and Marine SciencesBldg., Santa Cruz 95064 USA

Our ability to track long term climate change incoastal regions is limited in temperate and polar re-gions. Physical oceanographic dynamics in tempera-ture and upwelling events can be recorded as carbonand oxygen stable isotope signals in carbonate pro-ducing organisms. Because coralline algae photosyn-thesize, produce calcium carbonate and are widelydistributed, they may provide a new tool for detectingshort-term change. However, little is known abouthow coralline algae incorporate stable isotopes intotheir calcite thallus structure. The objectives of thisstudy were to determine if growth and isotopic signa-ture differ in articulated coralline algae grown in dif-ferent oceanographic regimes in Monterey Bay. Thearticulated alga Calliarthron cheiliospororioides was out-planted at three locations varying in seawater temper-ature and upwelling strength. New algal growth wasmeasured by staining the algae with Alizarin Red andenumerating the amount of accumulated material atthe branch tips. Growth rates varied seasonally andspatially. Low-upwelling daily growth rates averaged0.044–0.056 mm day21, while high-upwelling growthrates were 0.083 mm day21. Isotope ratios were ob-tained by analyzing microsampled portions of the algain a mass spectrometer. Changes in the 18O/16O and13C/12C ratios appear to reflect change in seawatertemperature and upwelling strength, respectively.

58PRELIMINARY ANALYSIS OF QUANTITA-TIVE GENETICS AND PHENOTYPIC PLAS-TICITY IN AULACOSEIRA SUBARCTICA(BACILLAR-IOPHYTA)Edgar, S. M., & Theriot, E. C.Section of Integrative Biology, University of Texas atAustin, Austin TX 78713 USA

Several clones of Aulacoseira subarctica were isolatedfrom Yellowstone, Lewis, and East Rosebud Lakes(Montana, Wyoming). Two to four clones from eachlake were grown in batch cultures under three light in-tensities, 2, 11.4 and 115 mE m22 s21. Clones were con-ditioned to their light environment for a three-weekperiod. Inoculants from the conditioned clones takenduring log phase of growth, were grown until in logphase, then samples were collected. Five randomly cho-sen valves for 2 replicates of each clone were examinedusing a scanning electron microscope and captured onfilm at a magnification of 20,000x. Each image was digi-tized and quantitative morphometric characters weremeasured. A preliminary quantitative genetic analysiswas performed on selected characters within each lightenvironment. Plasticity of characters within clonesacross the three light regimes were also examined. Theamount of variability found within characters in A. sub-arctica will be discussed in terms of environmental, ge-netic, and microenvironmental sources.

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59SCALE-DEPENDENT PATTERNS OF DISTUR-BANCE AND RECOVERY IN GIANT KELPFORESTSEdwards, M. S.1 & Hernandez-Carmona, G.21Department of Biology, University of California,Santa Cruz, CA 95064 USA; 2CICIMAR-IPN, Lapaz,Baja California Sur, 23,000 Mexico

We studied spatial variability in giant kelp (Macrocystispyrifera) forests at 84 sites along the west coast ofNorth America in order to assess the impacts of the1997–98 El Niño. Our sites spanned the geographicrange of giant kelp in the Northern Hemisphere andwere surveyed just before, immediately following, sev-eral months after, more than one year after, andnearly two years after the El Niño. Interspersion ofsample units allowed us to compare the effects of thisdisturbance among spatial scales ranging from a fewmeters to more than a thousand kilometers. Variancecomponents analyses revealed that El Niño shifted therelative importance of factors that regulate giant kelpcommunities from factors acting at the scale of a fewmeters (local control) to factors operating at hun-dreds of kilometers (regional control). Moreover, ElNiño resulted in a near-to-complete loss of giant kelppopulations throughout nearly two-thirds of the spe-cies’ range. Evaluation of these effects along withoceanographic data (at the “appropriate” spatialscales), along with closer examination of giant kelppopulations in the most severely impacted region(Baja) suggested that the among-region differences ingiant kelp survival was due, at least in part, to El Niño-induced differences in ocean climate. Giant kelp re-covery following El Niño was also scale-dependent,but driven by factors different from those of the dis-turbance. Here, we present results for several speciesof macroalgae in an attempt to relate the importanceof El Niño to that of other processes in creating scale-dependent patterns of variability.

60VARIATION IN TOXIN PRODUCTION OFSYNCHRONIZED CULTURES OF CHRYSOCH-ROMULINA POLYLEPIS (PRYMNESIOPHYTA)Eschbach, E.1, John, U.1, Reckermann, M.2 &Medlin, L. K.11Alfred-Wegener-Institute for Polar and Marine Re-search, PO Box 120161, 27515 Bremerhaven, Ger-many; 2Research and Technology Centre Westcoast ofKiel University, Hafentoern, 25761 Buesum, Germany

In European coastal waters toxic blooms of Prymne-siophytes occur regularly. Chrysochromulina polylepis is ahighly toxic member of this taxonomic group, whichformed a devastating bloom in Scandinavian waters in1988. Blooms like these can cause severe damage to

benthic and pelagic communities and can result inmillion dollar losses for commercial fisheries andmariculture of fin and shellfish. Effective preventionand mitigation strategies require an understanding ofenvironmental factors that contribute to the forma-tion of harmful algal blooms, as well as informationon the regulation of algal toxicity at the molecularlevel. To approach the latter aspect, we investigatedthe variation in toxin production of synchronized C.polylepis cultures by means of a sensitive bioassay andby flow cytometry. The results so far obtained showsignificant variation in cellular toxin content and spe-cific toxin production throughout the sampling pe-riod of three days. The existence of times in the cellcycle of high and low levels of toxin production willbe used as the basis for the identification of differen-tially expressed genes and proteins using differentialdisplay and 2-D protein gel electrophoresis. Prelimi-nary results concerning the molecular analysis will bepresented as well.

61CO-OCCURRENCE OF CARRAGEENANS ANDAGAROIDS IN GYMNOGONGRUS TORULO-SUS (GIGARTINALES, PHYLLOPHORACEAE)FROM ARGENTINAEstevez, J. M., Ciancia, M .& Cerezo, A.S.Departamento de Química Orgánica, Facultad deCiencias Exactas y Naturales, Universidad de BuenosAires, 1428 Buenos Aires, Argentina

The red seaweeds, Gigartina skottbetgii and Sarcothaliacrispata, have commercial value as raw material for theindustrial production of phycocolloids (carrageen-ans) in Argentina. The third alga with potencial possi-bilities for the carrageenan production is Gymnogon-grus torulosus. Herein, we report the study of thepolysaccharide system present in Gymnogongrus torulo-sus, which contribute to the estimation of the impor-tance of this algae in the seaweed industry. Analysis ofthe hot water-soluble extract (C1), by FT-IR, methyla-tion and 13C NMR, showed mainly the presence ofiota/kappa carrageenan hybrid (molar ratio z 2:1).The soluble fractions obtained after KCl fractionation(F3, 16.1 % of C1) and soluble after alkaline treat-ment and KCl fractionation (F3T3, 34.6% of F3T)gave negative optical rotations (215.5 and 255.4, re-spectively), considerably lower than those reportedfor kappa/iota carrageenans (from 56.1 to 66.5).These fractions (F3 and F3T3) have significant quan-tities of L-galactose (11.1% and 29.8%) and L-3,6-an-hydrogalactose (19.2% and 4.3%). The direct rela-tionship between the optical rotation and thepercentage of L-galactose indicated that its structuralinfluence is similar in all the fractions. The resultssuggest that Gymnogongrus torulosus biosynthesizes apolysaccharide system with co-occurrence of carrag-eenans and agaroids in the same thallus.

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62PHOTOSYNTHESIS IN THE DEEP BLUE SEA:PHOTOPHYSIOLOGICAL RESPONSES OFPHAEODACTYLUM TRICORNUTUM TO DY-NAMIC AND STATIC IRRADIANCESEvens, T. J.1, 2 & Chapman, D. J.21United States Department of Agriculture-AgriculturalResearch Service, Southern Regional Research Center,1100 Robert E. Lee Blvd., New Orleans, LA 70124USA; 2Department of Ecology, Evolution & Marine Bi-ology, University of California, Santa Barbara, CA93106 USA

The kinetics of xanthophyll-cycle pigment switchingand fluorescence quenching dynamics in the marinediatom, Phaeodactylum tricornutum were determined inthe context of dynamic and static growth light. Cul-tures were grown in a modified photobioreactor capa-ble of producing dynamic light fields which exhibitedattenuation characteristics similar to that of water;these cultures were pre-acclimated to high and low,static and dynamic, growth-light regimes for at leastthree days, and then examined under high, static anddynamic light. Pigment pools varied markedly. Thetwo static light cultures had pigment complementsthat were very similar to “traditional” high and low-light static cultures. The dynamic-light grown cultureshad pigment complements, which were very similar toeach other but different from the static-grown cul-tures. The maximum xanthophyll-cycle pigment de-epoxidation state attainable under saturating lightwas equal for all four treatments. Induction of fluores-cence quenching was significantly faster in the static-grown cultures, while xanthophyll-cycle de-epoxida-tion rates did not show as much variation. Minimumirradiances for xanthophyll-cycle induction were cor-related to average growth irradiance. Taken as awhole, the results from this work suggest that dynamiclight-grown phytoplankton have a unique photosyn-thetic functionality that is different from static light-grown phytoplankton. The significance of these ob-servations in the context of realistic light fields, andthe photosynthetic response capabilities of algaegrown under them will be discussed.

63HETEROGENEITY OF CHLOROPLASTGAPDH GENES IN THE DINOPHYCEAEFagan, T. F. & Hastings, J. W.Department of Molecular & Cellular Biology, HarvardUniversity, 16 Divinity Avenue, Cambridge MA02138 USA

Dinoflagellates provide valuable models for studyingendosymbiosis and chloroplast evolution. While manyspecies are heterotrophic, photosynthetic species con-taining plastids of different evolutionary origin have

been isolated, indicating that dinoflagellates acquiredchloroplasts multiple times during evolution. Further-more, dinoflagellates contain nuclear genes encodingchloroplast proteins that are not typically found in eu-karyotes. These include the type II form of RuBisCO,and a eubacterial form of glyceraldehyde-3-phosphatedehydrogenase (GAPCp) that we have recently char-acterized from Gonyaulax polyedra. The evolutionaryorigin of this GAPCp isoform is unclear. It is phyloge-netically distant from the Gonyaulax cytosolic form(GAPC) and from the chloroplast forms (GAPA/B) ofcyanobacterial origin typically found in photosyn-thetic eukaryotes. It has previously been describedonly from cryptomonads, raising the possibility thatGonyaulax acquired the gene through lateral transfer.We have addressed this issue by examining the phylog-eny of GAPDH genes from other dinoflagellates. Wehave isolated genes from Gymnodinium mikimotoi andPyrocystis lunula. The predicted protein sequence ofthe G. mikimotoi gene is 47% similar to GonyaulaxGAPC and GAPCp and phylogenetic analysis placesthem in the same eubacterial clade. The predictedamino acid sequence of the P. lunula gene is 41% and37% similar to Gonyaulax GAPCp and GAPC isoforms,respectively. However, phylogenetic analysis groups itwithin the clade comprising cyanobacterial and eukary-otic GAPA/B isoforms and shows that it is closely re-lated to the chloroplast form of Euglena gracilis. Thus,within the Dinophyceae, GAPDH genes of differentevolutionary origin have been recruited to participatein chloroplast metabolism.

64CLONING, SEQUENCING AND EXPRESSIONOF A HISTONE-LIKE PROTEIN FROM THEPHOTOSYNTHETIC DINOFLAGELLATEGONYAULAX POLYEDRAFagan, T. F.1, Li, J. F.1, Chudnovsky, J.1, Rizzo, P.J.2, & Hastings, J. W.11Department of Molecular & Cellular Biology, Har-vard University, 16 Divinity Avenue, Cambridge MA02138, USA; 2Biology Department, Texas A&M Uni-versity, College Station, TX 77843, USA

The presence of small basic DNA-binding proteins, orhistone-like proteins (HLPs), in dinoflagellate nucleihas been well documented. Genes for HLPs have beencloned from Crypthecodinium cohnii (HCc 1 and 2) andAlexandrium fundyense (HAf) but their predicted pro-tein sequences show no homology to histones fromother eukaryotes or to bacterial HLPs. The preciserole of these HLPs in dinoflagellate nuclei is uncer-tain; the HLP:DNA ratio is too low to facilitate packag-ing of the entire (very large) genome. In order to in-vestigate the role of these proteins we have cloned agene for a HLP from Gonyaulax polyedra (HGp). Unlikethe genes from C. cohnii, the G. polyedra gene containsno introns. It codes for a protein with a predicted mo-

22 PSA ABSTRACTS

lecular mass of 10,985 Da, and an isoelectric point of10.5. We over-expressed this protein in Escherichia coliusing a construct that expresses the full-length proteinwith an N-terminal histidine tag, and purified it byNickel-affinity and cation-exchange chromatography.While the predicted molecular mass of the fusion pro-tein is 12,973 Da, similar to sizes observed for acid-sol-uble G. polyedra nuclear proteins, the relative mobilityon denaturing SDS-polyacrylamide gel electrophore-sis is 20,000 Da. We attribute the slower mobility in de-naturing page to the basicity of the protein and pre-dict that the relatively faster mobility exhibited bynative HGp is due in part to post-translational modifi-cation of basic residues. Such modifications havebeen observed in histones and play an important rolein the regulation of transcription in eukaryotes, afunction that HLPs may assume in dinoflagellates.This possibility is being investigated.

65BIODIVERSITY OF PLANKTONIC DINO-FLAGELLATE SPECIES IN MANGROVEPONDS, PELICAN CAYS, BELIZEFaust, M. A.Department of Botany, NMNH, Smithsonian Institu-tion, Suitland, MD 20746 USA

Information on the population structure of plank-tonic dinoflagellates is reported in the coral reef-man-grove ecosystem at Pelican Cays, Belize. Six sites ex-amined included: Cat Cay, Douglas Cay, Elbow Cay,Fisherman’s Cay, Lagoon Cay and Manatee Cay. Aspectacular and rich dinoflagellate taxa includingoceanic, coastal and offshore species are illustrated.The presence of oceanic species in the studied cays isan unexpected observation since dinolfagellate as-semblages are virtually enclosed within ponds bor-dered by coral ridges that limits water exchange withthe open ocean except during storm events. I am alsoreporting significant differences in the dinoflagellateassociations among the studied cays. Dominant taxaincluded 16 Proroperidinium species, 11 Gonyaulax spe-cies, and ten Ceratium species. Only six planktonic spe-cies were harmful. Bloom forming species includedCeratium furca and Gonyaulax polygramma. A muchmore diverse authotrophic and heterotrophic di-noflagellate population characterizes the Pelican Caysthan previously suspected. Some species are reportedthe first time: Protoperidinium belizeanum sp. nov., P.pyrum Balech, P. steidingerae Balech, P. depressum(Bailey) Balech, and P. divergens (Ehrenberg) Balech.These results demonstrate that the Belizean coralreef-mangrove ecosystem is a delicate and species-richenvironment, and as such, should be protected andpreserved.

66ALGAE AS WATER QUALITY INDICATORSFOR A DYSTROPHIC PONDFerguson, E., Mosto, P., Nordone, N., Perez, C.III., & Wojs, J.Department of Biology, Rowan University, Glassboro,NJ 08028, USA

The physico-chemical, bacteriological, and algal com-position of R.U.Bi.S. Pond were studied since March1999. The pond, located in Cape May County, NJ, is adystrophic body of water, with high sediment:water ra-tio and organic matter content creating anoxic condi-tions during fall and early winter. Water quality indi-cators based on periphytic algae and water qualityindices that are specific to R.U.Bi.S. Pond are beingdeveloped. Such indicators could be used for similarbodies of water and for the restorability of this dystro-phic ecosystem integrity. Two sampling sites werestudied. Samples were collected weekly, using a per-iphytometer, for seasonal analysis of succession. Sam-ples for water chemistry, bacteriology, and periphyticalgae were collected bi-monthly. The predominant al-gal species found during summer ‘99 were Phormid-ium, Oscillatoria, Chlorella, and Eunotia. During fall ‘99,the predominant species were Oscillatoria and Phormid-ium. In winter, the community was dominated by Chlo-rella and Chlamydomonas. Species present year-roundwere Nitzschia, Oedogonium, Eunotia, and Navicula.Data analysis indicated variations among the two sam-pling sites, with total cell counts and species diversityhigher at the northern site. Algal cell counts, chlor-phyll a concentrations, species diversity, and D.O. lev-els were greatest during summer. Biomass, hardness,HPCs and total organic carbon peaked during thefall. Nutrients, pH, and coliforms remained constantduring the study period. The predominant algaefound were pollution-tolerant genera, categorizingthe pond as highly dystrophic. Species diversity indi-ces indicated that water quality decreased during thefall/winter months, with the southern site being moreenvironmentally stressed than the northern site.

67PHYLOGENY, BIOGEOGRAPHY AND LIFEHISTORY EVOLUTION IN THE RED ALGALFAMILY PHYLLOPHORACEAE (GIGARTINA-LES)Fredericq, S. & Lopez-Bautista, J. M.Department of Biology, University of Louisiana atLafayette, LA 70504 USA

Red algae are exceptional for the great diversity in re-productive morphology and for their complex life his-tories. In particular, the family Phyllophoraceae, con-sisting of z100 species worldwide, stands out inexhibiting a wide spectrum of unique life history typesthat makes it unusually interesting for assessing the

PSA ABSTRACTS 23

phylogenetic importance of reproductive traits rela-tive to classification criteria. Type of life history andposition of the reproductive structures on the plantbody have traditionally formed the basis for separat-ing eleven genera in the Phyllophoraceae; however,phylogenetic analyses inferred from three sets of DNAsequences [chloroplast-encoded rbcL, nuclear large-subunit ribosomal RNA gene (LSU), and internaltranscribed spacer regions (ITS) of nuclear ribosomalDNA], instead indicate a lack of correlation betweentype of life history and phylogenetic relationshipsamong the established taxa. This lack of correlationdramatically challenges all of the traditional taxon-omy. The study will answer the question which mor-phological features and which aspects of life historyevolution can be used as meaningful indicators ofphylogenetic relationships in the Phyllophoraceae.The results are addressed in light of global biogeo-graphic hypotheses for the family.

68CHARACTERIZATION OF THE OFFSHOREMARINE MACROALGAE FROM THE NORTH-WESTERN GULF OF MEXICO HARD BANKCOMMUNITIESFredericq, S., Phillips, N., Gavio, B., Gurgel, C.F., Lin, S. M., Wysor, B., & Lopez-Bautista, J. M.Department of Biology, University of Louisiana atLafayette, Lafayette LA 70504 USA

The upper northwestern Gulf basin is characterizedby a relatively shallow but well-developed continentalshelf with an extensive system of mid- and outer shelfhard banks of varying origin and composition. Obser-vations done by our laboratory while participating inmonitoring cruises to the National Marine Sanctuar-ies of the East and West Banks of the Texas FlowerGardens, Stetson Banks (TX) and Sonnier Banks(LA) reveal a surprisingly different floristic composi-tion among the sites. Several range extensions, newmacro-algal records for the Gulf of Mexico, and newspecies imply a much more complex Algal Zone com-munity than the one proposed by Rezak et al. (1985).Our ongoing project includes the development of amodern taxonomic, phylogenetic, morphological andgenetic database essential to informed managementfor preservation of biological diversity. It also providesa framework of seasonal algal composition againstwhich long-term trends and anomalies in algal distri-bution and health of the Gulf of Mexico can be as-sessed at future dates.

69LIGHT HARVESTING ANTENNAE SYSTEMS:LESSONS FROM SIMPLE ALGAE, THE ROLEOF SCIENTISTS, AND TRENDSGantt, E.

Department of Cell Biology & Molecular Genetics, Uni-versity of Maryland, College Park, MD 20742, USA

Algae, with their variety of pigmentation and extantevidence of primary to tertiary endosymbiotic states,present rich opportunities for exploring evolutionaryrelationships. A strong link is suggested by the conser-vation of phycobilisome structure between red algalchloroplasts and cyanobacterial progenitors. Althoughphycobilisomes are the major antennae of photosys-tem II reaction centers in both groups, a chlorophyll(Chl)-carotenoid light-harvesting complex (LHC)evolved in rhodophytes around the photosystem I re-action centers. LHC-polypeptides of all eukaryotic al-gae and green plants have high conservation of 8 pu-tative Chl-binding sites on three trans-membranehelices, yet many different types of Chls and caro-tenoids serve in light harvesting in diverse algalgroups. In view of the phylogenetic relatedness ofLHC polypeptides (Durnford et al. 1999, J. Mol. Evol.48:59) the Chl and carotenoid-binding capability wasexamined with pigments from diverse algae. A recom-binant P. cruentum polypeptide, LHCaR1, reconsti-tuted with its own pigments functionally bound about8.0 Chl a, and 4.0 zeaxanthin, comparable to native itspolypeptides. Upon reconstitution with diatom pig-ments 7 Chl a, 1 Chl c, and 10 xanthophylls werebound per polypeptide, which participated in energytransfer to Chl a. Spinach pigments also bound to thepolypeptide, incorporating a total of 8 Chl (both aand b) and ca. 4 xanthophylls, with energy transferfrom lutein and Chl b to Chl a. These results suggestthat the red algal LHCs retained the flexibility to binddifferent types of Chls and carotenoids. Such an an-cestral feature may have contributed to the successfulradiation of photosynthetic algae into varied light en-vironments.

70CURRENT STATUS OF THE INVASIVEGREEN ALGA CODIUM FRAGILE IN EASTERNCANADAGarbary, D. J. & Jess, C. B.Department of Biology, St. Francis Xavier University,Antigonish, Nova Scotia B2G 2W5 Canada

Ten years after the initial discovery of Codium fragile ineastern Canada on the Atlantic coast of Nova Scotia,C. fragile has extended its range considerably to north-ern Nova Scotia, southern New Brunswick and PrinceEdward Island (P.E.I.) in the Gulf of St. Lawrence. Inall principal areas C. fragile subsp. tomentosoides ispresent. In two regions of Prince Edward Island, Co-dium is becoming extremely abundant, and is knownby local fishers as the “oyster thief”. A potential sec-ond taxon of Codium was collected in 1999 at threesites in Malpeque Bay where it is locally abundant.These plants are distinguished from C. fragile subsp.

24 PSA ABSTRACTS

tomentosoides by their smaller frond size, flatter utricletops, smaller mucrons, and smaller gametangia. Prin-cipal component analysis distinguishes plants of thetwo types. The abundance of C. fragile on both hardbottom and soft bottom substrata suggests that it willbecome the dominant alga in many subtidal algalcommunities in eastern Canada.

71BIOGEOGRAPHY AND ECOLOGY OF THEKELP/RED ALGAL SYMBIOSISGarbary, D. J.1 & Kim, K. Y.21Department of Biology, St. Francis Xavier University,Antigonish, Nova Scotia B2G 2W5 Canada;2Department of Oceanography and Institute of MarineSciences, Chonnam National University, Kwangju500757 Korea

A kelp/red algal symbiosis is described from naturebased on extensive collections from the San Juan Is-lands, Washington. Kelp gametophytes were found asendophytes in the cell walls of seventeen species ofred algae in three different kelp communities. Hostred algae were mostly filamentous (e.g., Pleonosporiumvancouverianum) or polysiphonous (e.g. Polysiphoniapaniculata). The kelp gametophytes completed vege-tative and reproductive development in the hosts withgametangia formed at the host surface and withsporophytes up to several mm in height being pro-duced while still attached to the host. To date, noneof the kelp gametophytes from nature have beenidentified to genus or species, although the gameto-phyte of Nereocystis luetkeana is a potential candidatefor the symbiosis. Preliminary observations from NovaScotia and the Isle of Man have not found the associa-tion in the Atlantic Ocean. Laboratory studies in Ko-rea successfully reconstructed the symbiosis in the redalga Aglaothamnion oosumiense using zoospores ofUndaria pinnatifida but not Laminaria religiosa. Herewe outline the development of the symbiosis and dis-cuss the potential adaptive significance of the kelp/red algal interaction.

72PHYLOGENETIC AND BIOGEOGRAPHICAFFINITIES OF THE HALYMENIALES ANDRHODYMENIALES (RHODOPHYTA) FROMTHE GULF OF MEXICOGavio, B.1, Fredericq, S.1, Mendoza-Gonzalez,C.2, Mateo-Cid, L.2, Aguilar-Rosas L. E.3, &Aguilar-Rosas, R.31Department of Biology, University of Louisiana atLafayette, LA 70504 USA; 2Depto. de Botanica, Es-cuela National de Ciencias Biologicas, I.P.N., MexicoD.F, Mexico; 3Instituto de Investigaciones, Oceanologi-cas, Universidad Autonoma de Baja California,Ensenada, B.C., Mexico; 4Facultad de Ciencias Mari-

nas, Universidad Autonoma de Baja California,Ensenada, B.C., Mexico

Generic and species concepts within the red algal as-semblages Halymeniales and Rhodymeniales are dis-cussed for taxa inhabiting the western Gulf of Mexico.Two principal biogeographic assemblages occur: anoff-shore deep-water group (including Coelarthrum clif-tonii, Halymenia spp., Botryocladia spp., Gloiocladia) rep-resenting remnants of a Tethyan distribution, and anear-shore intertidal flora (comprising Rhodymenia,Grateloupia and Prionitis) which instead reveals biogeo-graphic affinities with the Carolinian Province. Thesetwo distinct marine floras will be contrasted phyloge-netically based on DNA sequence analysis inferredfrom chloroplast-encoded rbcL. The generic descrip-tions of Grateloupia and Prionitis are in need of taxo-nomic revision based on a survey of species from Car-ibbean and Pacific Mexico.

73FUNCTIONAL BINDING OF DIATOM PIG-MENTS TO A RHODOPHYTE LIGHT HAR-VESTING POLYPEPTIDEGrabowski, B., Cunningham, F. X., & Gantt, E.Cell Biology and Molecular Genetics, University ofMaryland, College Park, MD 20742 USA

A close relationship of light harvesting polypeptides(LHC) of rhodophytes, chromophytes and chloro-phytes is inferred from the amino acid sequence simi-larity in three transmembrane helices, and from the con-servation of 8 putative chlorophyll (Chl)-binding sites(Durnford et al. 1999, J. Mol. Evol. 48:59). Differencesin Chl and carotenoid pigments have been a majorclassification feature. Thus, it was of interest to ascer-tain whether pigments from a diatom (Thallasiosira flu-viatilis) could be functionally inserted into a red algal(Porphyridium cruentum) polypeptide. A recombinantpolypeptide, LHCaR1, was reconstituted with pigmentextracts from the diatom (Chls a and c, fucoxanthin,diadinoxanthin and b-carotene). The pigments werefound attached to protein upon separation on sucrosegradients, and on non-denaturing gels. Absorptionand fluorescence excitation spectra revealed individ-ual peaks corresponding to the absorption maxima ofChl a at 438/672 nm; Chl c at 463/638 nm; and fucox-anthin at 493/540 nm. Fluorescence emission and CDspectra showed functional binding and suitable orien-tation for energy transfer from Chl c and carotenoidsto Chl a. The LHCaR1 successfully folded in the pres-ence of the heterologous pigments and bound 7 Chla, 1 Chl c, 8 fucoxanthin, and 1.9 diadinoxanthin perpolypeptide. By comparison, this polypeptide with P.cruentum pigments binds 8 Chl a, and 4 zeaxanthins,thus revealing its capability of functionally binding 8Chls with variations in carotenoid numbers. Such atrait may have favored the diversification of a large

PSA ABSTRACTS 25

family of LHCs and the successful radiation of photo-synthetic eukaryotes into different light environ-ments.

74THE SECRET LIFE OF KELPS: PLANKTONICPROCESSES AND POPULATION DYNAMICSGraham, M. H.Scripps Institution of Oceanography, University of Cal-ifornia San Diego, San Diego, CA 9209 USA

Understanding spatio-temporal variability in recruit-ment is vital to studies of kelp population dynamics.Research on settlement and post-settlement processeshas suggested that arrival of kelp zoospores to suitablesubstrate is important in limiting kelp recruitment,yet the role of planktonic processes in kelp popula-tion dynamics has not been studied due to difficultiesin sampling and identifying zoospores. I developed amethod to estimate kelp zoospore abundance from insitu plankton samples and used it to study various pro-cesses regulating the availability of giant kelp (Macro-cystis pyrifera) zoospores for settlement. My studies fo-cused on (1) identifying temporal scales over whichzoospore abundance is most variable, (2) describingphysical and biological processes that regulate thisvariability, and (3) determining the relationship be-tween zoospore abundance and settlement. I foundthat short-term variability in zoospore abundance(,24 hrs) was not due to changes in supply but ratherdispersion, caused by oscillating hydrodynamic forces(e.g. waves). Long-term variability in zoospore abun-dance, however, was best explained by the size anddensity of reproductive adult plants, with zoosporeabundance being most variable at the scale of days tomonths. Changes in adult reproductive conditioncaused rapid changes in zoospore abundance suggest-ing that the supply of kelp zoospores is sensitive to en-vironmental regulation of adult physiology. Thus, un-like with marine animals, these results indicate thatvariability in kelp propagule supply, over scales mostlikely to affect subsequent settlement and recruit-ment, is more tightly coupled to demographic and re-productive mechanisms than to physical transportprocesses.

75LET THERE BE LIGHT (BUT NOT TOOMUCH): MOLECULAR EVOLUTION OFLIGHT-HARVESTING COMPLEXESGreen, B. R.Botany Department, University of British Columbia,Vancouver, BC V6T 1Z4 Canada

The light-harvesting antennas common to all photo-synthetic eukaryotes belong to two protein familes:the Chl a-binding core complex family (e.g. CP47,CP43), and the LHC superfamily, whose members

bind a variety of Chls. The former are all chloroplast-encoded and have high sequence similarity to theircyanobacterial homologs; the latter are all nucleus-en-coded and have a much more complex relationshipwith each other and their (presumed) cyanobacterialancestors. Phylogenetic analysis of the LHC superfam-ily protein sequences show that they follow the endo-symbiotic history of their hosts and suggest that theancestral cyanobacterial genes were copied to the nu-cleus soon after the establishment of the primary en-dosymbiosis. Both families have members whose roleappears to be related to photoprotection rather thanlight-harvesting, suggesting that these families mayhave originated as stress-response proteins. In supportof this, all members of the LHC superfamily bind sig-nificant amounts of carotenoid, and much of the vari-ation between them resides in the bewildering arrayof different carotenoids they bind. In fact, it has beensuggested that this family originated as carotenoid-binding proteins and only later acquired Chl (Gantt,E. 1998; Photosynthesis: Mechanisms & Effects I, pp. 239-246).

76HIGH BREVETOXIN CONCENTRATIONS INGYMNODINIUM BREVE BLOOMS ALONGTHE NORTHWEST FLORIDA COAST DUR-ING 1999Greene, R. M., Walker, C. C., Murrell, M. C.,Kurtz, J. C., Stanley, R. S., & Genthner, F. J.Gulf Ecology Division, National Health and Environ-mental Effects Research Laboratory, United States En-vironmental Protection Agency, 1 Sabine Island Drive,Gulf Breeze, FL 32561 USA

Blooms of the dinoflagellate Gymnodinium breve (i.e.red tides) produce brevetoxins (PbTx) that negativelyimpact the Gulf of Mexico ecosystem, human health,and local economies. Characterizing and predictingbloom events and their impacts requires knowledgeof G. breve abundance and PbTx concentrations in thewater column. We report results from a bloom thatoccurred during the fall and winter of 1999 in NWFlorida coastal waters. Data were collected from 16stations on 3 sampling dates (29 Sept., 9 Nov., 1 Dec.),including basic hydrography, nutrient concentra-tions, G. breve abundances, and brevetoxin concentra-tions. G. breve cells were enumerated using flow cytom-etry and PbTx’s were isolated from seawater usingdichloromethane (DCM) partitioning. Brevetoxinswere quantified by HPLC-DAD using a C-18 columnand an acetonitrile-water gradient elution. Literatureestimates of total PbTx concentration (PbTx’s 1, 2, 3)of cultured and field-collected G. breve suggest a rangein concentration from 7 to 17 pg cell21. We measuredtotal PbTx levels that greatly exceeded these values[Sept., 47–67 pg cell21 (n55); Nov., 59–126 pg cell21

(n53), Dec., 12–63 pg cell21 (n58)]. PbTx-2 was the

26 PSA ABSTRACTS

predominant (67–75%) PbTx isomer found in theseblooms. PbTx-1 and PbTx-3 were found at 11–22%and ND–28% of total PbTx, respectively.

77EXTRACELLULAR MATRIX PROTEO-GLY-CANS INVOLVED IN DIATOM ADHESIONAND MOTILITYGretz, M. RDepartment of Biological Sciences, Michigan Techno-logical University, Houghton, MI 49931 USA

Although diatom extracellular matricies are usuallythought of exclusively in terms of the beautiful, archi-tecturally complex silicious frustule, polymers exudedthrough the frustule are critical mediators of interac-tions with the external environment. In several spe-cies, complex proteoglycans appear to be the primarycomponents involved in adhesion and motility. Whenviewed with high-resolution cryo-scanning electronmicroscopy methods, the ubiquity and pervasivenessof these polymers was revealed in both freshwater andmarine taxa. Monoclonal antibody mapping of carbo-hydrate epitopes characterized by NMR, methylationand monosaccharide analysis and correlated withstructural observations by EM revealed an organiza-tional pattern far more complex than previously pro-posed. Modeling assembly of extracellular “stalks” inthe marine biofouling diatom Achnanthes longipes in-volves intracellular sequestering of multiple compo-nents, deposition at the protoplasmic membrane/diatotepum interface, transport through the multilay-ered diatotepum and holes in the silica, extrusionfrom the frustule, and assembly into a very complexmulti-laminate biocomposite structure. The mecha-nism of extracellular polymer participation in motilityis complex in a different way, as some current modelsof raphe associated motility involve cytoskeletal inter-actions and molecular motors.

78CULTURES OF CHYTRIDS - PARASITES OFALGAE IN BIOLOGICAL INSTITUTE OFPETERSBURG UNIVERSITYGromov, B. V., Mamkaeva, K. A., & Pjusch, A.V.Laboratory of Microbiology, Biological Institute of St.Petersburg University, Oranienbaumskoye sch., 2, StaryPeterhof, St. Petersburg,198904 Russia

During our survey of chytrids occuring on algae infresh waters in the northwestern part of the RussianFederation we never observed mass development ofparasites, but if cultures of Chlorococcum minutum Starror Tribonema gayanum Pasch. were inoculated with asample of water (0.5 L), the parasites appeared in10% of the cases. Two-clonal (alga and parasite) cul-tures were obtained by plating of the material on thelawn of algal cells on the solid medium with benzyl

penicillin. 22 cultures are now available. For the mostpart, cultures belong to Rhizophydium species. Chytrid-ium lagenula (Braun) sensu Scherffel is grown on Tri-bonema gayanum cells. Cultures differ in possible hostrange, where some have a very wide host range, butothers grow only on the cells of Chlorococcum minutum(from 40 strains of different clorococcalean algae ex-amined). Only two Rhizophydium spp. cultures are op-portunists and grow on dead algal cells and organicmedia. Collection is used for the examination of in-teraction between algae and fungi.

79IMPACT OF STRESS CONDITIONS ON THEPHOTOSYNTHETIC MACHINERYGrossman, A. R.1, van Waasbergen, L.2, &Schwarz, S.31Department of Plant Biology, The Carnegie Institutionof Washington, Plant Biology, 260 Panama Street,Stanford, CA 94305 USA; 2Department of Biology,University of Texas at Arlington, Arlington, TX76019 USA; 3Department of Plant Sciences, The He-brew University of Jerusalem, 91904 Jerusalem, Israel

Organisms sense their environment and attempt totune their metabolism to ambient conditions to effi-ciently utilize available resources. Cyanobacteria un-der conditions of stress (nutrient limitation, excesslight) modify the photosynthetic apparatus by elimi-nating most photosystem II activity and degradingtheir light-harvesting complex or phycobilisomes(PBS). We have identified cyanobacterial mutants thatcannot acclimate normally to nutrient deprivation.One of these mutants has a lesion in a gene encodinga small polypeptide designated NblA that appears totarget the PBS for degradation during nutrient limita-tion. A second lesion is in the nblB gene, which en-codes a polypeptide with homology to a family oflyases involved in attaching chromophores to apophy-cobiliproteins. This protein may remove bilin chro-mophores from phycobiliprotein subunits prior totheir degradation. A third mutant is defective in nblR,which encodes a transcription factor that controlssome of the “general” responses that occur during anyof a number of different stress conditions. It is re-quired for degradation of PBS and appears to be nec-essary for controlling photosynthetic activity duringboth nutrient limitation and high light conditions;this control is critical for survival of cells during condi-tions of environmental stress. A fourth mutant is al-tered in nblS, which encodes a sensor kinase thatplays a role in regulating both nutrient stress and highlight responses. This sensor protein has a PAS do-main, appears to binds a flavin, and integrates the re-sponse of the cell to a variety of stress conditions; itmay sense the redox status of the cell. I will present amodel that describes how cyanobacteria sense and re-spond to environmental change.

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80 MOLECULAR STUDY OF THE TOXIC ALGAEDINOPHYSIS SPP. FROM THE FRENCHCOASTGuillou, L.1, Nezan, E.2, Gentien, P.3 & Barbier, G.11IFREMER Brest, DRV/VP/CMM, BP 70, 29 280Plouzané, France; 2IFREMER Concarneau, DEL/CC,13 rue de Kérose, Le Roudouic, 29187 Concarneaucedex, France; 3IFREMER La Rochelle, DRV/RA/CREMA, Place du séminaire, BP 7, 17137L’Houmeau, France

Dinoflagellates of the genus Dinophysis are agents ofDiarrhetic Shellfish Poisoning (DSP). They occuralong the French coast and affect shellfish exploita-tion during most of the year (during spring, summerand autumn). Because this species is difficult to culti-vate, very little is known about this organism. The firstproblem is the species-delineation within this genuswhich is sometimes unclear based upon the solely onmorphological features, in particular for the complexD. acuminata (D. cf. acuminata,, D. cf. norvegica, D.cf.sacculus, and D. skagii) or the complex D. sacculus(D. sacculus and D. pavillardii). The second problem isits detection in natural samples. French Dinophysisblooms have been reported to be toxic under 100cells L21, a concentration which corresponds to lessthan 1 cell 10-mL21, as determined by the Utermöhlmethod of enumeration. Molecular tools may help toresolve these two kind of problems. During one year(spring 1999 to spring 2000), more than 100 fixedsamples containing Dinophysis spp. cells were collectedalong the French coast by the French monitoring net-work (or REPHY; http://www. ifremer.fr). The ge-netic diversity of Dinophysis spp. was studied by se-quencing and analysis of ribosomal DNA genes. Wefound that sequences were hightly conserved betweenspecies or within the D. acuminata or D. sacculus com-plex. Two oligonucleotide probes, specific to thesecomplex groups, were designed. Their specificity andsensitivity are actually tested on natural samples by aPCR-based assay. Furthur investigation will includethe development of standard molecular diagnosticsdue to their rapid and sensitive detection in naturalsamples.

81GRACILARIA FROM THE GULF OF MEXICO,WITH SPECIAL EMPHASIS ON GRACILARIATIKVAHIAE BASED ON TWO MOLECULARDATASETSGurgel, C.F.1, Fredericq, S.1, & Norris, J. N.21Department of Biology, University of Louisiana atLafayette, LA 70504 USA; 2Department of Botany,NMNH, Smithsonian Institution, Washington D.C.,20560 USA

Despite a recent body of literature, the species ofGracilaria recognized for the Gulf of Mexico are stillincompletely characterized, misidentified, and spe-cies limits not well defined due to huge morphologi-cal plasticity and overlapping habits. To better charac-terize these taxa and evaluate their taxonomicrelationships, we provide a chloroplast-encoded rbcLphylogeny encompassing primarily Gulf, western At-lantic, and Caribbean species. Our results indicate theneed to resurrect older, validly published names cur-rently placed in synonymy under other species ofGracilaria, and to describe new species. For Gracilariatikvahia, in particular, a combination of DNA se-quences [rbcL, and internal transcribed spacer re-gions (ITS) of nuclear ribosomal DNA] from speci-mens collected across a wide biogeographic area(Nova Scotia, Canada, to Las Coloradas, Yucatan Pen-insula) successfully promotes the integration and cor-relation of molecular phylogenies and morphologywith biogeographic hypotheses.

82PHYLOGEOGRAPHY AND WITHIN-STREAMGENETIC VARIATION OF BATRACHOSPER-MUM HELMENTOSUM (RHODOPHYTA) USINGINTER-SIMPLE SEQUENCE REPEATSHall, M. M. & Vis, M. L.Department of Environmental & Plant Biology, OhioUniversity, Athens, OH 45701 USA

A relatively new molecular marker technique, inter-simple sequence repeats (ISSR), was used to assess thewithin-stream reach genetic variation and phylogeog-raphy of the freshwater red alga, Batrachospermum hel-mentosum. The within-stream reach study was under-taken in Southeastern Ohio, where 58 individualswere collected from an approximately 200 m streamlength. Individuals appeared to be congregated intothree distinct areas, with no plants between areas. Us-ing three primers, 100 polymorphic bands werescored. Although it was hypothesized that genetic vari-ation would reflect physical distance, the resultsshowed six distinct genetic groupings, some of whichconsisted of physically distant individuals. Overall, ge-netic diversity was greater among individuals than be-tween geographic and genetic groups. To investigatephylogeography, 11 stream reaches (3 from Ohio andone each from Connecticut, Massachusetts, Rhode Is-land, North Carolina, Tennessee, Indiana, Michiganand Louisiana) were sampled throughout the alga’sknown distribution in North America. Approximately15 individuals were collected per stream for ISSRanalysis. Five primers, yielding 243 polymorphicbands, were used to examine variation among all indi-viduals. Neighbor-joining trees generated from theDice, Jaccard and Excoffier coefficients showed thatindividuals from the same stream formed a clade.Among streams there was no distinct correlation be-

28 PSA ABSTRACTS

tween geographic distance and genetic similarity.Genetic groupings varied slightly among distance co-efficients employed. Michigan and Tennessee, Con-necticut and Rhode Island, and Indiana and Massachu-setts streams consistently showed the same relationship,but the relationships among the three Ohio streamsand Louisiana stream were variably related to eachother.

83MACROALGAL TISSUE NUTRIENTS AS INDI-CATORS OF NITROGEN AND PHOSPHORUSSTATUS IN THE FLORIDA KEYSHanisak, M. D. & Siemon, L. W.Harbor Branch Oceanographic Institution, Fort Pierce,FL 34946 USA

This study used the tremendous biochemical and eco-logical diversity of macroalgae to assess nitrogen andphosphorus availability at a broad, ecosystem-levelscale in the Florida Keys and nearby waters. Spatialvariation in tissue nutrients (carbon, C; nitrogen, N;phosphorus, P) of dominant macroalgae were as-sessed, both as ratios and absolute values, along 12 in-shore-offshore transects in the Florida Keys and at 10stations in nearby Florida Bay. The resulting detailedanalysis demonstrated spatial and temporal patternsin macroalgal tissue nutrients. The transect data re-vealed no universal inshore-offshore patterns in tissuenutrients and no obvious “hotspots” of nutrient en-richment. Similarly, when data were compared amongsegments, there was no universal geographical patternin tissue nutrients for all species. The most striking re-sult was that the N and P status of macroalgae in Flor-ida Bay was significantly different than other loca-tions. Macroalgae collected from Florida Bay generallyhad higher N and lower P levels than algae collectedelsewhere. The most common inshore-offshore pat-tern was higher %N and lower %P availability inshore;however, limited inshore-offshore differences in N:Pratio suggests that both nutrients were generallyreadily available in proportional amounts required bythe various species. Most species in this study hadhigher %N, and to a lesser extent, higher %P and %Cin March than in July. Based on the published litera-ture on other species of macroalgae, it appears that Nand P are generally available in sufficient quantitiesthat most macroalgal growth is not limited by eithernutrient.

84GRATELOUPIA DORYPHORA HAS ESTAB-LISHED RESIDENCY IN RHODE ISLANDWATERSHarlin, M. M.1 & Villalard-Bohnsack, M. 21Department of Biological Sciences, University of RhodeIsland, Kingston, RI 02881 USA; 2Biology Depart-

ment, Roger Williams University, Bristol, RI 02809USA

Since 1994, when Grateloupia doryphora (Halymeniaceae,Rhodophyta) was first detected in Rhode Island, thespecies has spread to the northern portions of Nar-ragansett Bay and onto the open coast of Rhode Is-land Sound. Specimens collected at 5 m depths offNorth Prudence Island reached 175 cm in length andestablish this alga as the largest member of theFlorideophyceae on North Atlantic shores. Percentcover of populations is seasonal: highest in fall (Sep-tember through November) and lowest in spring(March through May). Monthly measurements atthree stations in Narragansett Bay show significantseasonal differences (p , 0.01) over two annual cy-cles. Artificial substrata placed in the field at knownperiods allowed measurements of growth rates on in-dividual thalli. Laboratory culture clarified the se-quence of life history stages that make this species asuccessful contender for space.

85A REEXAMINATION OF THE SYSTEMATICSOF THE ACROCHAETIALES (RHODOPHYTA)USING LARGE-SUBUNIT RDNA SEQUENCEDATAHarper, J. T. & Saunders, G. W.Department of Biology, University of New Brunswick,Fredericton, NB, E3B 6E1, Canada

The taxonomic history of the red algal order Acrocha-etiales is chaotic. There is no consensus in the litera-ture as to how many genera should be recognized orin the assignment of the over 400 species to these gen-era. Morphological and anatomical studies have pro-vided a suite of possible characters to delineate gen-era within this order, but there have been majordiscrepancies in the assessment and use of these fea-tures. The phylogenetic placement of the Acrocha-etiales has also been the focus of debate. Once thoughtto be the most ancestral florideophyte lineage, recentmolecular systematic studies have illustrated that thisorder is a derived lineage closely related to the Nema-liales and Palmariales. Phylogenies using sequences ofthe small-subunit (SSU) rDNA have strongly sup-ported two very divergent lineages within a possiblypolyphyletic Acrochaetiales. The relationships betweenthese two groups and among other closely relatedrhodophyte orders were not resolved. We have gener-ated large-subunit (LSU) rDNA sequence data forrepresentatives of the Acrochaetiales and related taxa.Distance and parsimony phylogenies based on LSUand combined SSU and LSU data will be presented.The increased phylogenetic signal afforded by this ap-proach will shed light on previous conundrums in thesystematics of this group.

PSA ABSTRACTS 29

86INTRAGENOMIC NRDNA ITS POLYMOR-PHISM IN THE STEPHANODISCUS NIAGARAECOMPLEX (BACILLARIOPHYCEAE)Hartung, L. L , Goertzen, L. R. , Theriot, E. C.Department of Integrative Biology, The University ofTexas at Austin, Austin, Texas 78713 USA

Intragenomic nrDNA ITS variability was examined inrepresentative species of the Stephanodiscus niagaraecomplex. PCR was performed on DNA extracted frommonoclonal cultures, and sequence variability de-termined using standard cloning techniques. Pre-liminary data from all species reveal intragenomicpolymorphism. ITS sequence data is being used to de-lineate closely related species of algae and polymor-phisms are potentially problematic for phylogeneticreconstruction and identity. We are exploring the ex-tent of polymorphism in other freshwater Thalassior-siraceae, including Stephanodiscus hantzschii fo. tenuisand Cyclostephanos invisitatus.

87SYSTEMATICS OF ULVACEAE (ULVOPHY-CEAE, CHLOROPHYTA) USING NUCLEARAND CHLOROPLAST DNA SEQUENCESHayden, H. S. & Waaland, J. R.Department of Botany, Box 355325, University ofWashington, Seattle, WA 98195 USA

Ulvaceae are morphologically simple, cosmopolitangreen macroalgae. Family members, particularly spe-cies of Ulva and Enteromorpha, are prevalent in coastalecosystems and responsible for “green tide” eventsaround the world. Little is known about the evolution-ary history of Ulvaceae. A lack of reliable, non-molec-ular systematic characters has thwarted attempts todiagnose natural groupings within Ulva and Enteromor-pha and among these and other putative Ulvaceaegenera. Our study addresses several questions: 1)What are the phylogenetic relationships among gen-era commonly placed in Ulvaceae (Chloropelta, Entero-morpha, Ulva, Ulvaria); 2) Where do problematic gen-era such as Blidingia, Capsosiphon, Kornmannia, andPercursaria belong; and 3) What are the natural group-ings of taxa within these genera? We address thesequestions using nuclear and chloroplast DNA se-quences. Phylogenetic analyses support a monophyl-etic Ulvaceae consisting of Chloropelta, Enteromorpha,Percursaria, Ulva and Ulvaria. The systematic positionof Blidingia, Capsosiphon and Kornmannia, and evolu-tionary relationships within selected genera will bediscussed.

88BIOLUMINESCENCE IN THE MARINE DINO-FLAGELLATE PYROCYSTIS LUNULAHeimann, K.1, Matuszewski, J.1, Stiffey, A. V.2 &Klerks, P. L.11Department of Biology, University of Louisiana atLafayette, Lafayette, LA 70504 USA; 2Lumitox GulfL.C., Environmental Testing Laboratory, 1928 B Cor-porate Square, Slidell, LA 70458 USA

Marine dinoflagellates are the main contributors to aphenomenon commonly known as “phosphorescenceof the sea”. Several investigators using different di-noflagellate species have shown that dinoflagellate bi-oluminescence is regulated by a circadian rhythm.Diverse bioluminescent systems exist in different or-ganisms; however, all systems utilize an enzyme lu-ciferase and the substrates luciferins, which show in-ter-species cross-reactivity. In marine dinoflagellates,luciferase and luciferin are localized in specific or-ganelles, termed scintillons, which are usually locatedin close proximity to the vacuole during their activestate. Bioluminescence is stimulated by mechanicalstress or by acidification of the medium. Nicolas andco-workers (1987, J. Cell Biol. 105: 723-735) suggestedthat bioluminescence is triggered by an acidificationof the scintillon caused by events that depolarize thetonoplast (proton trigger model). However, little isknown about the signal transduction cascade that re-lays the mechanical stimulus perceived at the plasmamembrane to the tonoplast. This study investigatesthe response of the bioluminescent system of Pyrocystislunula to various parameters such as age of culture,light quality and quantity, disturbance (handling),sensitivity to chemicals, etc. to determine, if the biolu-minescent response of P. lunula suitable for measur-ing environmental toxicants. The assay system usedmeasures bioluminescence in response to mechanicalstimuli or acidification allowing us to determine, ifthe response varies amongst the two different types ofstimulation under different experimental conditions.The use of cell-permeant inhibitors for certain signal-ing pathways in this assay may help to biochemicallycharacterize events involved in signal transductionfrom the plasma membrane to the scintillon.

89REPRODUCTIVE, CULTURE AND REGENER-ATION STUDIES OF THE EDIBLE RED ALGACALLOPHYLLIS IN CHILEHernández-González, M. C., Aroca, G., Filœn, L.& Buschmann, A. H.Departamento de Acuicultura, Universidad de Los La-gos, Casilla 933, Osorno, Chile

In Chile, the demand of edible seaweeds has in-creased during recent years and Callophyllis variegata

30 PSA ABSTRACTS

is one of the most demanded species. This study sum-marizes information on phenology, aspects, in vitroculture and vegetative propagation methods for Callo-phyllis. Results indicate that spore production occursmainly during winter, and recruitment of new plantsappear in nature in the spring. Culture studies indi-cate that spores presented higher germination andgrowth rates at 88 C and 10 to 12 mmol m22 s21. Fur-thermore, these results indicate that this species pre-sents a high potential for regeneration from its hold-fast. The manipulation of temperature, light andculture medium enhances the regeneration processand growth of Callophyllis in the laboratory.

90PHYLOGENY OF ZYGNEMOPHYCEAE BASEDON COXIII GENE SEQUENCE DATAHewitt, D.1, Karol, K. G.2, & McCourt, R. M.31Department of Biology, University of Pennsylvania,Philadelphia, PA 19104; 2Department of Cell Biologyand Molecular Genetics, H. J. Patterson Hall, Univer-sity of Maryland, College Park, MD 20742; 3Departmentof Botany, Academy of Natural Sciences, 1900 Ben-jamin Franklin Parkway, Philadelphia, PA 19103

Molecular phylogenetic analysis of the conjugatinggreen algae (Class Zygnemophyceae) using nuclear(SSU rDNA) and chloroplast (rbcL) gene sequenceshas resolved hypotheses of relationship at the class,order, and family levels, but several key questions willrequire data from additional genes. Based on SSUand rbcL sequences, the Zygnemophyceae and Des-midiales are monophyletic, and families of placodermdesmids are distinct clades (Desmidiaceae, Peniaceae,Closteriaceae, and Gonatozygaceae). In contrast, theZygnemataceae and Mesotaeniaceae are paraphyletic,although whether these two traditional families con-stitute a clade is uncertain. In addition, relationshipsof genera within families have proven resistant to res-olution with these two oft-used genes. We have se-quenced the coxIII gene from the mitochondrial ge-nome to address some of these ambiguous portions ofthe phylogeny of conjugating green algae. The coxIIIgene is more variable than rbcL or SSU rDNA and of-fers greater resolving power for relationships of gen-era. We present preliminary analyses of coxIII se-quences from each of the traditional families ofZygnemophyceae and contrast the resulting topolo-gies with those derived from nuclear and chloroplastgenes.

91CLONING AND CHARACTERIZATION OFNITRATE TRANSPORTER GENES FROMTHE DIATOM CYLINDROTHECA FUSIFORMISHildebrand, M. & Dahlin, K.

Marine Biology Research Division, Scripps Institutionof Oceanography, University of California, San Diego,9500 Gilman Dr., La Jolla CA 9209 USA

We have cloned and characterized the first nitratetransporter genes in a marine organism, from the dia-tom Cylindrotheca fusiformis. A cDNA clone and two ge-nomic sequences, NAT1 and NAT2, were isolated.The sequences were highly conserved, with only 9 outof 484 amino acids differing. At least four copies ofNAT genes were present in C. fusiformis, and multi-ple copies were present in other diatom species. NATtranscript abundance was high in cultures grown inthe presence of nitrate, at nearly the same level dur-ing nitrogen starvation, and also high in urea-growncultures. Lower mRNA levels occurred in nitrite-grown cultures. Transcript levels were highly re-pressed with NH4Cl or NH4NO3 as the nitrogensource, although very low amounts were detected.NAT mRNA levels were not directly regulated by lightor dark. NAT mRNA levels varied, suggesting that ni-trate uptake was not continuous, during progressionthrough the cell cycle. The results suggest that tran-scriptional control contributes significantly to theoverall control of nitrate uptake in C. fusiformis. Thecloning of the nitrate transporter genes provides anew tool for investigating diatom nitrogen uptake andmetabolism. In addition, the regulation of NAT ex-pression by nitrogen source is likely to be useful in de-veloping techniques to specifically control the expres-sion of genes fused to NATregulatory sequences intransgenic diatoms.

92A MOLECULAR MOTOR FOR GLIDINGMOTILITY IN CYANOBACTERIAHoiczyk, E.Laboratory of Cell Biology, The Rockefeller University,New York, NY 10021 USA

Motile microorganisms either swim, by using flagellaor glide over surfaces by mechanisms that are poorlyunderstood. In cyanobacteria, gliding motility ap-pears as a relatively slow and smooth surface-associ-ated translocation in the direction of the long axis ofthe filaments at rates up to a few micrometers a sec-ond. Many filamentous species translocate in a highlycoordinated manner. Translational movements areusually accompanied by revolutions around the longaxis of the filament. While moving, the cyanobacteriasecrete slime which is left behind as a twisted and col-lapsed thin tube. The observation of the slime secre-tion process shows that the mucilage is formed as finebands that emerge in close proximity to the cells crosswalls. Ultrastructural studies have revealed that the cy-anobacteria possess at their cross walls complex, pore-like organelles, which might be involved in slime se-cretion. As each cell possess two different sets of pores

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pointing in opposite direction, the coordinated activ-ity of these structures could explain how the filamentcan reverse the direction of locomotion. Further-more, ultrastructural studies have shown that rotatingcyanobacteria possess cell surfaces formed by parallel,helically arranged surface fibrils. As the arrangementof these fibrils corresponds with the path of the fila-ments during locomotion, it might be imaginable thatthese fibrils serve as screw thread guiding the rotationof the filaments, with the necessary thrust for locomo-tion being derived from the secretion of slime usingthe pores at the cross walls.

93EXPERIMENTAL STUDY OF PHYTOPLANK-TON SPECIES COMPOSITION, ALTERNATESTATES, AND COMMUNITY BREAKPOINTSALONG A PHOSPHORUS GRADIENTHolz, J. C.1, Hoagland, K. D.1, & Joern, A.21School of Natural Resource Sciences, University of Ne-braska, 103 Plant Industry, Lincoln, NE 68583 USA;2School of Biological Sciences, University of Nebraska,348 Manter Hall, Lincoln, NE 68583 USA

A model combining algal mortality due to selectivezooplankton grazing with the Monod model of phy-toplankton growth was used to predict phytoplanktonspecies composition along a gradient of phosphorus(P) concentration and zooplankton grazing pressure.Model predictions were compared to the results of amesocosm experiment of phytoplankton species com-position along a range of P concentrations of five to115 mg L21 and potential grazing loss rates of 0.001 to0.27 day21. The effect of the P gradient was measuredby monitoring phytoplankton and zooplankton spe-cies composition and biomass, and physical andchemical parameters for seven weeks in 12 fiberglasstanks (5500 L) filled with lake water and associatedplankton. P concentrations were manipulated so thattanks were evenly distributed along the gradient. Us-ing laboratory derived Monod growth constants for Pand literature values of phytoplankton selectivity coef-ficients, zooplankton filtering rates, and zooplanktonassimilation efficiencies, the model correctly pre-dicted (1) the existence of alternate communitystates, (2) breakpoints between the alternate stateswhich are similar to the P concentrations definingVollenweider’s lake trophic states, and (3) phy-toplankton species composition along the P gradientin the mesocosm study. These results suggest that thetrade-off between competitive ability for P and edibil-ity is a primary factor structuring phytoplankton com-munities, and that multiple states exist which may beconsistent with the long-standing P-based lake trophicclassification.

94SIGNIFICANCE OF PHYLOGENETIC SYS-TEMATICS FOR THE BIOGEOGRAPHY OFTHE MARINE RED ALGAEHommersand, M. H.1, Fredericq, S.2, &Freshwater, D. W.31Department of Biology, University of North Calolina,Coker Hall, Chapel Hill, NC 27599 USA; 2Departmentof Biology, University of Louisiana at Lafayette, Lafay-ette, LA 70404 USA; 3Center for Marine Science Re-search, 5001 Masonboro Loup Rd., Wilmington, NC28409 USA

Hovencamp (1997) recommends that geographicalinformation can be extracted from cladistic analysesof phylogenetic data in which the Earth’s history is re-solved in terms of vicariance events that establishedbarriers to migration. Nodes in a cladogram that spec-ify two sister groups which do not overlap in their dis-tributions are taken as evidence for a vicariance eventand the sequential order of cladogram nodes leads toa procedure whereby the sequence of vicarianceevents can be reconstructed. For red algae, two suchevents are the persistence of the northward extensionof the eastern end of Gondwanaland across a cool towarm temperature gradient with the formation ofpresent-day Australasia, and the opening of theTethyan Ocean followed by closure of the TethyanSeaway between Africa and Eurasia. Phylogenetic hy-potheses related to the first of these events are seenamong genera belonging to the Bonnemaisoniaceae,Gracilariaceae, Kallymeniaceae, Gigartinaceae, andDelesseriaceae. A Tethyan origin and distribution isexemplified in part by families that comprise the So-lieriaceae complex. Orders such as the Rhodyme-niales, Halymeniales and the families Ceramiaceaeand Rhodomelaceae contain taxa that fall partly intothe first and partly into the second category. Phyloge-nies are constructed from rbcL sequence data andcompared to the morphological evidence. The bio-geographical speculations resulting from these obser-vations are preliminary in nature and can only be con-firmed or refuted with addtional data and morerefined analytical techniques.

95THE COLONIAL GREEN ALGA ASTREPHO-MENE GUBERNACULIFERA DISPLAYS ACHEMORESPONSE TO ACETATEHoops, H. J., Cocina, A. E., Binder, D. S. andWidjaja, A.Biology Department, State University of New York atGeneseo, 1 College Circle, Geneseo, NY 14454 USA

Astrephomene gubernaculifera is a colonial green alga ca-pable of growth on sodium acetate in the dark. Be-cause heterotrophic organisms often have mecha-

32 PSA ABSTRACTS

nisms to detect and respond to food sources, wetested the response of A. gubernaculifera to a numberof potential chemoeffectors. Acetate elicits strongchemoaccumulation in three different behavioral as-says. However, there was no chemoaccumulation inresponse to the carbohydrates xylose, ribose, glucose,galactose, mannose, arabinose, fructose, maltose, lac-tose, and sucrose; the amino acids asparagine, argin-ine, cysteine, glutamine, glycine, histidine, isoleucine,lysine, phenylalanine, serine, threonine, and hydrox-yproline; or glycerol. Interestingly, A. gubernaculiferadid respond to propionate. This compound isstructurally related to acetate, but is incapable of sup-porting growth in the dark. This implies that thechemosensory response in A. gubernaculifera is not thedirect result of metabolic changes but rather involvesa specific chemical receptor and subsequent internalsignaling pathway. We are presently analyzing swim-ming patterns in colonies exposed to changes in ace-tate concentration to test several alternate modelsthat could lead to chemoaccumulation.

96ALGAL-RELATED TASTES AND ODORS INPHOENIX WATER SUPPLY: PRELIMINARYREPORTHu Q.1, 2, Dempster T.1, Lowry D.1, SommerfeldM.1, Westerhoff, P.2, Bruce, D.2, Nguyen, M. L.2,& Baker L. 31Department of Plant Biology, Arizona State Univer-sity, Tempe, AZ 85287 USA; 2Department of Civil andEnvironmental Engineering, Arizona State University,Tempe, AZ 85287 USA; 3Backer Environmental Con-sulting, 1134 E. Vinedo Lane, Tempe, AZ 85284 USA

Frequent episodes of algal-related tastes and odors (T& O) in drinking waters in metropolitan Phoenix, Ari-zona prompted initiation of a three-year project inJuly 1999 to investigate the occurrence of T & O me-tabolites and to develop a comprehensive manage-ment strategy to reduce the problems in drinking wa-ter supplies in arid environments. Two metabolites, 2-methylisoborneol (MIB) and geosmin, have beenidentified as compounds responsible for the earthy-musty tastes and odors in water supplies. Both weredetected in the water supply system, including sourcerivers, reservoirs, canal delivery system and watertreatment plants. Higher concentrations of MIB andgeosmin occurred in distribution canals than in theupstream reservoirs indicating that significant pro-duction of the T & O compounds occurs within thecanal system. A baseline-monitoring program hasbeen established for the complex water supply system,with special emphasis on the canal system. Efforts areunderway to investigate possible correlations betweenphysical/chemical parameters, algal composition andbiomass, with the occurrence of MIB and geosmin. Inaddition, several physical and chemical treatments are

planned for the canal system to reduce algal growthand related MIB and geosmin concentrations.

97A SYSTEMATIC STUDY OF GIGAR-TINACEAEFROM PACIFIC NORTH AMERICA BASEDON MOLECULAR AND MORPHOLOGICALEVIDENCEHughey, J. R. & Hommersand, M. H.Department of Biology, University of North Carolina,Chapel Hill, NC 27599 USA

Greater than 50 species of Gigartinaceae have beendescribed from Pacific North America, about half ofwhich are currently recognized. Although the familyis treated extensively in the taxonomic literature,many of the species are still confused and a compre-hensive revision is required. We sequenced the rbcL(RuBisCO) gene and ITS (Internal TranscribedSpacer) 1, 2, and 5.8S regions from a large number ofrecent collections and identified a discrete of numberdata sets. These were analysed in comparison with themorphological evidence for each of the taxa. Uncer-tain of the possibility that our operational taxonomicunits may not correspond to the types, we developed aprotocol for isolating PCR-friendly DNA from herbar-ium specimens, some reaching back as far as 1670.The DNA profiles of types and historically importantspecimens were compared to those for recently col-lected silica gel-dried and formalin-fixed material andassigned correct names. Species studied ranged fromAlaska to Mexico and the Gulf of California and werecompared to outgroup taxa from Pacific South Amer-ica and the Southern Ocean. Particular attention waspaid to variations in morphology as they relate to hab-itat with emphasis on the presence or absence of dif-ferent morphological forms among sympatric and al-lopatric populations. We recognize 10 species inChondracanthus (including one new combination andone new species) and 16 species in Mazzaella (includ-ing two new combinations and two new species). Fi-nally, we tested a phylogenetic hypothesis inferred forthe Gigartinaceae from rbcL sequences for congru-ence with one generated from ITS sequences.

98QUALITATIVE AND QUANTITATIVE STUD-IES OF THE SWIMMING BEHAVIOR OFHINCKSIA IRREGULARIS SPORES (PHAEO-PHYCEAE)Iken, K. B., Amsler, C. D., Greer, S. P., &McClintock, J. B.Department of Biology, University of Alabama at Bir-mingham, Birmingham, AL 35294 USA

The swimming behavior of spores of the brown algaHincksia irregularis was analyzed using computer-assisted

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motion analysis. We distinguished five main swim-ming patterns: straight paths, search circles, orienta-tion, gyration, and wobbling. We suggest differentfunctional values for the individual swimming pat-terns. Straight paths, search circles, and orientationare different but all may be important in small-scalemovements in the benthic boundary layer. As such,they could enable a spore to find a suitable microenvi-ronment for germination and growth. Gyration oc-curs during the initial reversible phase of adhesionthat can lead to settlement. Wobbling is typical for ir-ritated or mechanically damaged spores and does notseem to be a typical pattern associated to settlement.The dominant swimming patterns changed with sporeage (10 6 5 to 60 6 5 min of spore age), with youngspores mainly swimming in straight paths and searchcircles and older spores in orientation and gyration.This change in swimming patterns can be quantifiedby speed (decrease over time) and rate of change ofdirection (increase over time). Based on these results,we suggest that computer-assisted motion analysis ofthe swimming behavior of H. irregularis spores can beused to develop bioassays with both ecological andtechnological relevance.

99A NOVEL BIOFOULING ASSAY USING COM-PUTER-ASSISTED MOTION ANALYSIS OFHINCKSIA IRREGULARIS SPORE SWIMMINGIken, K. B., Greer, S. P., Amsler, C. D., &McClintock, J. B.Department of Biology, University of Alabama at Bir-mingham, Birmingham AL 35294 USA

Computer-assisted motion analysis of the swimmingbehavior of spores of the brown alga Hincksia irregu-laris was used in a novel antifouling bioassay. Newly re-leased spores were exposed to water soluble com-pounds of organic and aqueous body wall extracts oftwo sympatric sea stars, Astropecten articulatus and Lu-idia clathrata. Changes in the swimming behavior of H.irregularis spores were quantified by changes in speed(decrease at extract exposure) and rate of change ofdirection (increase at extract exposure). Sea star ex-tracts were tested at natural concentrations (mg ex-tract/g wet weight) and at approximate 10-, 100-, and1000-fold dilution. Significant effects (p # 0.05) wereobserved at 1000-fold dilution of the natural concen-tration in both extracts of A. articulatus, and at 100-and 10-fold dilution of the aqueous and organic ex-tract, respectively, in L. clathrata. Germination ofspores after short time exposure (30 min) to sea starbody wall extracts indicates that compounds were nottoxic but affected spore mobility, a factor that plays animportant role during spore settlement. We suggestthat this assay is very useful for bioassay-guided frac-tionation of extracts because it is very sensitive and re-quires only small amounts of extracts or isolated com-pounds.

100ENDOMEMBRANE ULTRASTRUCTURE ANDPOSSIBLE CHLOROPLAST PROTEIN IMPORTPATHWAY IN HETEROSIGMA AKASHIWO(RAPHIDOPHYCEAE)Ishida, K., Cavalier-Smith, T., & Green, B. R.Department of Botany, University of British Columbia,Vancouver, BC V6T 1Z4 Canada

Chloroplasts in heterokont algae probably originatedfrom a red algal endosymbiont which was engulfedand retained by a eukaryotic host, and are sur-rounded by four envelope membranes. The outer-most of these membranes is called chloroplast ER(CER) and usually connects with the nuclear enve-lope. This information, however, is based mainly onstudies on single-plastid heterokont algae. In multi-plastid heterokont algae, it is still unclear whetherCER is continuous with the nuclear envelope. Sincenuclear-encoded chloroplast proteins are synthe-sized by ribosomes on the ER membrane, clarifyingthe ER-CER structure in the heterokont algae is im-portant in order to know the targeting pathway ofthose proteins. We did a detailed ultrastructural ob-servation of endomembrane systems in a multi-plastidheterokont alga: Heterosigma akashiwo, and confirmedthat the CER membrane was continuous with the ERmembrane. However, unlike the CER membranes inother heterokont algae, it seemed to have very few ri-bosome attached. We also performed experiments forprotein targeting into canine microsomes using a pre-cursor for a nuclear-encoded chloroplast protein, afucoxanthin-chlorophyll protein (FCP), of H. akash-iwo, to see if the protein is targeted to the ER. It dem-onstrated that the precursor has a functional signal se-quence for ER targeting, and is co-translationallytranslocated into the microsomes. Based on thesedata, we propose a hypothesis that, in H. akashiwo, nu-clear-encoded chloroplast protein precursors thathave been co-translationally inserted into the ER lu-men are sorted in the ER and transported to the chlo-roplasts through the ER.

101ENHANCED GROWTH RATES OF THE GERM-LINGS OF CYANOBACTERIAL RESTINGSPORES (AKINETES)Jameson, I.1, Thompson, P. A.2, & Blackburn, S.11CSIRO Division of Marine Research, GPO Box 1538,Hobart, Tasmania 7001 Australia; 2School of Aquac-ulture, University of Tasmania, Locked Bag 1-370,Launceston, Tasmania, 7250 Australia

In experiments with the toxic cyanobacterium, Ana-baena circinalis, we investigated the nature of cyst for-mation and germination under different environmen-tal conditions (variation in light quality and quantity,

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temperature, nutrient limitation). We consistentlyfound that germlings up to about 5 days old hadgreater growth rates than those of vegetative cellsgrown under similar saturating irradiance and excessnutrient conditions in batch culture. Averaging theresults from 4 experiments, the specific growth rate(K9) fell from 1.9 d-1, 24 hours after germination to1.17, 1.04, 0.8, and to 0.45 d21 after 48, 72, 120 and144 hours, respectively. This equates to an increase ingeneration time from 0.37 to 1.54 days over this 6 dayperiod. To investigate the implications of these resultswe modelled two hypothetical populations, A & B,with an initial akinete or resting cyst concentration of10/mL each, but with population A having a standardgrowth rate of 0.45 and B with the 6 day early en-hanced growth rate as determined in our laboratoryexperiments. The model indicates that population Bquickly establishes dominance over population A. Inthis modeling exercise we have assumed a germina-tion frequency of 100% for both populations but ourlaboratory results indicate that even given optimumgermination conditions this factor may vary between5% and 90% depending on the age of akinetes andthe conditions experienced during dormancy (senes-cence). Some conditions that determine germinationfrequency were also investigated.

102RELATIONSHIP BETWEEN PERIODIC RESUS-PENSION EVENTS AND PHYTO-PLANKTONBLOOMS IN LAKE MICHIGANJulius, M. L. & Goad, L.Center for Great Lakes and Aquatic Sciences, Univer-sity of Michigan, 501 East University, Ann Arbor, MI48109 USA

Lake Michigan provides an ideal location for compar-ing episodic physical forcing effects (storm events) onphytoplankton processes and the more persistent sea-sonal variability of phytoplankton communities. Thisis because of the duration and extent of the highlyturbid, recurrent coastal plume (RCP) in the lakeduring the winter/early spring. Although the RCP co-incides with the initiation of the basin wide spring dia-tom bloom, linkages between the duration and inten-sity of the plume and the prominent role of lightavailability in regulating Lake Michigan phytoplank-ton growth during the spring isothermal period havebeen postulated, but not verified. As such the concur-rent physical and biological events provide a novel op-portunity to examine how variations in biological rateprocesses, coupled with transport and resuspensionphenomena associated with the RCP, affect the distri-butions of organisms, evolution of communities, andgrowth and primary production of Lake Michiganphytoplankton. In this study, phytoplankton assem-blages from pre, post, and active plume events are ex-

amined from three stations in Lake Michigan. Speciesassemblages include chlorophytes, chrysophytes, anddiatoms. The diatom flora was particularly abundant.Species composition changed rapidly during stormevents, with resting cell forming taxa playing a signifi-cant role in these modifications. Ephemeral speciesappeared during the circulation event and decreasedonce storm activity subsided. Other taxa were able toestablish themselves in the phytoplankton communityduring the plume events and persisted after storm ac-tivity subsided. Understanding activity during thesecirculation events will lead to a better understandingof overall community structure development through-out the year.

103PHYLOGENETIC ANALYSIS OF THE MARINEAND FRESHWATER THALAS-SIOSIROID DIA-TOMSJulius, M. L.1 & Theriot, E. C.21Center for Great Lakes and Aquatic Sciences, 501East University, 726 Dennison, The University ofMichigan, Ann Arbor, MI 48109 USA; 2Texas Memo-rial Museum, 2400 Trinity Street, University of Texas,Austin, TX 78705 USA

The thalassiosiroid centric diatoms are distinguishedby at least one synapomorphy, the strutted process orfultoportula. Variously classified as a family (Thalassi-osiraceae) or an order (Thalassiosirales) among cen-tric diatoms, it is generally conceded that the group ofseveral hundred fossil and living species is monophyl-etic as a whole. There are two ecological groups ofthalassiosiroids, marine and freshwater. It has beenhypothesized, based on an ecletic, non-rigorous, evo-lutionary taxonomy perspective that both the marineand freshwater ecological groups are also monophyl-etic, but this hypothesis has never been tested in a rig-orous framework. Likewise, the freshwater thalassio-siroid species have been grouped into several generaand subgenera using an evolutionary taxonomic ap-proach, but these hypotheses have not fully beentested using cladistic analysis. Focusing mainly onfreshwater species, but including at least one repre-sentative of each marine genus and one representa-tive from each of several proposed subgeneric group-ings of the genus Thalassiosira, we scored morphologicalcharacters for fossil and living marine and freshwaterThalassiosiraceae to test these hypotheses. Our cladis-tic results provide strong support for monophyly forthe freshwater group, but it seems unlikely that themarine group is monophyletic. The cladistic resultsare corroborated to greater or lesser degrees by thefossil record. The implications for evolution in thegroup and for taxon sampling in molecular studies weare conducting will be discussed.

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104PHYLOGENY OF THE BASAL LINEAGES OFSTREPTOPHYTA BASED ON RBCL AND ATPBGENE SEQUENCE DATAKarol, K. G.1, Delwiche, C. F.1, & McCourt, R. M.21Department of Cell Biology and Molecular Genetics,H. J. Patterson Hall, University of Maryland, CollegePark, MD 20742; 2Department of Botany, Academy ofNatural Sciences, 1900 Benjamin Franklin Parkway,Philadelphia, PA 19103

The streptophytes comprise the Charophyceae sensuMattox and Stewart (a morphologically diverse groupof fresh-water green algae) and the embryophytes(land plants). Several charophycean groups are cur-rently recognized. These include the Charales, Co-leochaetales, Chlorokybales, Klebsormidiales andZygnemophyceae (Desmidiales and Zygnematales).Recently, SSU rRNA gene sequence data allied Mesos-tigma viride (Prasinophyceae) with the Streptophyta.Complete chloroplast sequence data, however, placedMesostigma sister to all green algae, not with the strep-tophytes. Several morphological, ultrastructural andbiochemical features unite these lineages into amonophyletic group including embryophytes, but evo-lutionary relationships among the basal streptophytesremain ambiguous. To date, numerous studies usingSSU rRNA gene sequences have yielded differing phy-logenies with varying degrees of support dependentupon taxon sampling and choice of phylogeneticmethod. Like SSU data, chloroplast DNA sequencedata have been used to examine relationships withinthe Charales, Coleochaetales, Zygnemophyceae andembryophytes. Representatives of all basal strepto-phyte lineages have not been examined using chloro-plast data in a single analysis. Phylogenetic analyseswere performed using DNA sequences of rbcL (thegenes encoding the large subunit of rubisco) andatpB (the beta-subunit of ATPase) to examine rela-tionships of basal streptophyte lineages. Preliminaryanalyses placed the branch leading to Mesostigma asthe basal lineage in the Streptophyta with Chlorokybus,the sole representative of the Chlorokybales, branch-ing next. Klebsormidiales and the enigmatic genusEntransia were sister taxa. Sister to these, the Charales,Coleochaetales, embryophytes and Zygnemophyceaeformed a monophyletic group with Charales and Co-leochaetales sister to each other and this clade sisterto the embryophytes.

105THE PINGUIOPHYCEAE CLASSIS NOVA,CHROMOPHYTE ALGAE PRODUCING LARGEAMOUNTS OF OMEGA-3 FATTY ACIDSKawachi, M.1, Inouye, I.2, Honda, D.3, O’Kelly,C. J.4, Bailey, J. C.5, Bidigare, R. R.6, & Andersen,R. A.4

1National Institute for Environmental Studies,Tsukuba, Ibaraki 305, Japan; 2Biological Sciences,Tsukuba University, Tsukuba, Ibaraki 305, Japan;3Faculty of Science, Konan University, Kobe 658-8501Japan, 4Bigelow Laboratory for Ocean Sciences, WestBoothbay Harbor, ME 04575 USA; 5Biological Sci-ences, University of North Carolina-Wilmington, Wilm-ington, NC 28403 USA; 6Department of Oceanogra-phy, University of Hawaii, Honolulu, HI 96822 USA

A new class of algae is proposed for a small group ofunusual chromophytes (5heterokont algae). Onenovel aspect of these organisms is that cells containlarge amounts of polyunsaturated fatty acids (41 –67% of fatty acids), with exceptionally high amountsof EPA (21 – 56% of fatty acids). A second unusualcharacter is that, for at least two genera, the matureflagellum (short, smooth flagellum of other chro-mophytes) is dominant, and the immature flagellum(long, hairy flagellum of other chromophytes) lackstripartite hairs and is reduced in size or even absent.Carotenoid analysis shows that the class is character-ized by the presence of chlorophylls a and c, fucoxan-thin, violaxanthin, antheraxanthin, zeaxanthin, andb-carotene. The 18S rRNA and rbcL gene sequencesshow that these organisms form a monophyleticgroup that is supported by very high bootstrap values.The phylogenetic relationships of the Pinguiophyceaeand other classes are not well resolved, however, therelationships among the chromophytes have alwaysbeen uncertain. The abundance of EPA, known to re-duce “bad cholesterol” in humans, suggests this newclass may be of significant economic importance.

106REGENERATION OF PROTOPLASTS FROMDISINTEGRATED CELLS OF BRYOPSIS PLU-MOSA (DERBESIALES, CHLOROPHYTA)Kim, G. H., Klotchkova, T. A., & Kang Y.-M.Department of Biology, Kongju National University,Kongjushi, Chungnam 314-701, Korea

When injured, the protoplasms come out from themulti-nucleate giant cell of a green alga Bryopsis plu-mosa and can generate numerous new cells spontane-ously. The cell organelles aggregated rapidly in seawater and became covered with a gelatinous envelopewithin fifteen minutes. A lipid cell membrane wasformed inside the envelope within nine to twelvehours. Cytochemical studies using Nile Red and vari-ous enzymes revealed that the primary envelope is ini-tially composed of polysaccharides then becoming apolysaccharide-lipid complex. Fluorescein diacetate(FDA) staining showed that the primary envelope hassome characteristics of cell membranes includingsemipermeability and selective transport of materials.The aggregation of cell organelles appears to be me-diated by two kinds of material; one in vacuolar sap

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and the other on the surface of cell organelles. Abouta thousand new cells were generated from a single dis-integrated branch and forty percent of them eventu-ally developed into mature plants.

107PATTERNS OF RECRUITMENT AND DISTRI-BUTION OF ULVA AND ENTEROMORPHAPOPULATIONS IN A KOREAN INTERTIDALSHOREKim, J. H. & Park, S. R.Department of Biological Science, Sungkyunkwan Uni-versity, Suwon, 440-746 Korea

Patterns of recruitment and abundance of Ulva per-tusa and Enteromorpha linza in the three locations onthe south coast of Korea where green tide frequentlyoccurred were investigated with respect to the sub-strate profile, temporal and spatial variations, andtheir persistence. Artificial substrates (10 to 20 cm)were made of a mixture of a piece of granite rock andcement on ceramic tiles. These setting plates, repre-senting different surface texture, were placed hori-zontally and vertically along the rocky shoreline, andreplaced every 1 to 2 months. Both populationsshowed highly seasonal blooms, with peaks in Octo-ber, 1998 to February, 1999 and another slight peakwas observed in the fall of 1999 only for Ulva. How-ever, the winter peak of 1998 did not appeared in thefollowing year, indicating that a significant year-to-year variation existed. Regarding their settlementonto artificial plates with different roughness, Ulvapreferred to settle on the rough surface both in theupper and lower intertidal zone; however, this patternonly appeared in the upper zone for Enteromorpha.Vertical distribution of the two populations was wellseparated; Enteromorpha was more abundant in the up-per zone and Ulva in the lower zone. Their seasonalblooms were concomitant with ammonia levels, butoccurrence was not well correlated with nitrate andphosphate. The ability of the populations to persist,once blooms occurred, was also distinct; Ulva per-sisted ca. twice as long as Enteromorpha, having agreater impact in the presence of green tide in thisgeographical area.

108ULTRAVIOLET ABSORBING SUBSTANCESFROM AGARUM FIMBRIATUM (PHAEOPHY-CEAE) PROTECT GRIFFITHSIA PACIFICA FROMUV RADIATIONKim, K. Y.1, Garbary, D. J.2, Hoffmann, J.3, &Duggins D.41Department of Oceanography and Institute of MarineSciences, Chonnam National University, Kwangju500-757, Korea; 2Department of Biology, St. Francis

Xavier University, Antigonish, Nova Scotia, B2G2W5, Canada; 3Department of Zoology & 4FridayHarbor Laboratories, University of Washington, FridayHarbor, WA 98250, USA

We examined whether naturally occurring polyphe-nols produced by a brown alga can protect other or-ganisms from ultraviolet radiation. Fragments of Grif-fithsia pacifica were grown in medium supplementedwith a seawater extract of Agarum fimbriatum (3% w/vin seawater for 2 h). Cultures were exposed to cool-white fluorescent light (7–7.5 mMol photons cm22

s21) in the presence or absence of 130 to 168 mWcm22 UV-A and 85 to 112 mW cm22 UV-B. Regenerat-ing fragments were scored for five qualitative or quan-titative measures of growth. Rhizoid growth was notinhibited by the polyphenol extract after ten days. UVradiation in the absence of polyphenols caused con-siderable cell death and slower growth. Thus, the pres-ence of polyphenols provided protection from UV ra-diation such that in the highest concentration ofpolyphenols (1:1 medium:extract), rhizoid growth inUV exposed fragments was approximately 60% asgreat as control plants without both polyphenols andUV radiation. Plants exposed to UV radiation in theabsence of polyphenol extract showed poor rhizoidregeneration and extensive cell death. These experi-ments document the nature of UV-A and UV-B dam-age to growing red algae, and provide strong evidencethat polyphenols from brown algae may have a role inprotecting subtidal, benthic algal communities fromUV radiation.

109VERTICAL MIGRATION OF EUGLENA SP. ONTHE SAND BANKS OF A NORTH CAROLINAPIEDMONT STREAMKingston, M. B.Biology Department, Elon College, Elon College, NC27244 USA

On summer days, visible patches of green appearedon the aerially-exposed sand banks of a small tributaryof Mays Lake in Burlington, North Carolina. Thesegreen patches became visible approximately 3 hoursafter sunrise and disappeared 2 hours prior to sunset.Microscopic examination of sediment samples re-vealed that the appearance of color was due to the up-ward migration of Euglena sp. that attained densitiesof 2200 cells per square millimeter around solarnoon. Triplicate sediment cores revealed the pres-ence of live Euglena cells as deep as 6 cm below thesediment surface. During the day, over 80% of thepopulation was located between the surface and adepth of 2 mm. During the night, 75% of the popula-tion was found between 2 and 6 cm below the surface.Artificially darkening the sediment surface during theday stimulated downward migration of the popula-

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tion. Controlled experiments with neutral density fil-ters indicated that the number of cells on the sedi-ment surface was directly related to incident irradiance.The results of these experiments on Euglena sp. livingon the banks of a freshwater stream in central NorthCarolina will be contrasted with those of previous ex-periments conducted on Euglena proxima living on theintertidal sand flats of the Newport River estuary incoastal North Carolina.

110INFLUENCE OF ANTHROPOGENIC POLLU-TION ON MACROPHYTOBENTHOS OF THEAVACHA BAY (SOUTHEAST KAMCHATKA,RUSSIA)Klotchkova, N. G.1 & Berezovskaya, V. A.21Laboratory of Phycology, Kamchatka Institute of Ecol-ogy & Nature Management, Russian Academy of Sci-ences, Petropavlovsk-Kamchatsky, 683000 Russia;2Departament of Chemistry & Ecology, KamchatkaState Technical University, Petropavlovsk-Kamchatsky,683003 Russia

Most industrial and agricultural enterprises of the Ka-mchatsky district are situated along the coast of theAvacha Bay and its river drainage. Intensive water pol-lution resulted in extreme deterioration of the bay’secology. The destruction of macrophytobenthos un-der the influence of pollution was investigated. Mate-rials were regularly collected at the same samplingsites in different seasons of the year from 1988 up to1999. Analysis of our data allowed us to determine di-rections of long-term changes of species compositionand macrophytobenthos structure, speed of degrada-tion of different types of vegetational communitiesand reasons for all these processes. The Avacha Bay’sflora consisted of more than 160 species up to 1970s,including species belonged to 104 genera, 47 families,23 orders, 3 divisions (30 Chlorophyta, 48 Phaeo-phyta, 82 Rhodophyta). Flora of the internal part ofthe bay differed from that of the bay’s mouth andconsisted of 143 and 146 species, respectively. Pres-ently, the whole flora of the bay (internal part1throat) includes only 94 species. Along the urbancoast 18 poly- and mesosaprobious species are foundonly. They are characterized by small sizes, low pro-ductivity and short life cycles. Most of them areephemeral with a primitive morphology. The respon-sive reaction of algae to pollution resulted in de-creases in size and weight of the thalli, and appear-ance of anomalies of development. Laminariabongardiana was used as a bioindicator. The changesof weight and sizes of its plants allow us to determinedegree of the pollution in different parts of the coastof the Avacha Bay.

111SEASONAL VARIATIONS IN PHYTOPLANK-TON COMMUNITIES OF AN EPHEMERALPOND SYSTEM IN SOUTHEASTERN VIR-GINIAKokolis, M. R.Department of Biological Sciences, Old Dominion Uni-versity, Norfolk, VA 23529USA

The Grafton Ponds Natural Area is a 151 hectare pre-serve in York County, Virginia, approximately 56kmnorth of the City of Norfolk. The preserve containsover 40 ephemeral ponds. These ponds which arefilled seasonally by precipitation and groundwater dis-charge, are typically wet from late fall through latespring or early summer. Pond size varies from 0.1 to 2ha, and depths range from 4 cm to 3 meters. The firstphase of this study was to examine the physical andchemical characteristics of five of these ponds, includ-ing pond size and depth, inundation period, watertemperature, pH, and phosphate and ammoniumconcentrations. The second phase, which is currentlyunderway, is to examine the phytoplankton assem-blages, relating differences in the phytoplankton pop-ulations to the varying physical and chemical charac-teristics of the ponds. To date, analysis indicatesChlorophytes and Cyanobacteria as dominant groupsin the winter and spring with diatoms becoming moreabundant in the late summer and fall. Periodic Di-noflagellate blooms also occur. Analysis also indicatesrapid turnover of species from month to month.

112FIELD STUDY OF ALGAL RECRUITMENT BYCLEARING EXPERIMENT IN PING CHAU,HONG KONG SAR, CHINAKong, S. L. & Ang, P. O.Department of Biology, The Chinese University of HongKong, Shatin, N.T., Hong Kong SAR, China

Recruitment, the entry of new individuals into a popu-lation, was investigated by a clearing experimentalong the shore of A Ma Wan (AMW) in Ping Chau,Hong Kong SAR, China. Two types of clearing, withall the existing vegetation removed (cleared) and withthe top 2 to three mm of the rock surface removed(hammered), were carried out monthly in AMW fromNovember 1997 to June 1999. Observations weremade one month after clearing and on a monthly ba-sis thereafter. The number of algal species present onthe cleared areas and their percentage cover were re-corded. The experimental results showed that morealgal species were recruited during March and Aprilin 1998 (n510) but in 1999, the number of specieswas found higher in February and March (n58). Spe-cies richness dropped after May (more obvious in1998), indicating that recruitment greatly declined insummer. A tuft complex composed of several filamen-

38 PSA ABSTRACTS

tous algal species dominated over the others in allclearing areas (coverage mostly over 90%) but re-cruits of Caulerpa peltata, Colpomenia sinuosa, Enteromor-pha sp., Hypnea charoides, Padina spp., Sargassum sp.,Spyridia filamentosa, Ulva sp., etc. also were observedduring the study period. Generally, there were no sig-nificant differences in terms of species richness andcomposition of the recruits between the two treat-ments (cleared vs. hammered) as well as with the con-trols. This implied that algae in AMW were morelikely to be recruited de novo from elsewhere ratherthan regenerated from remnants of the previousyear’s growth.

113NUCLEAR RIBOSOMAL DNA PHYLOGENYOF HALIMEDALES REVEALS SEVERAL POLY-PHYLETIC GENERAKooistra, W. H. C. F.1 & Hillis, L. W.21S.T.R.I., Unit 09948, APO AA 34002-0948 USA &Department of Marine Biology, Biological Center, Post-box 14, 9750 AA Haren, The Netherlands; 220 BrooksRd., Woods Hole, Ma 02543 USA

Halimedales (Chlorophyta) are widely distributed inreefs and lagoons throughout the tropics and sub-tropics. One genus, Chlorodesmis, consists of simple,branching siphons that persist into the mature sexualphase. In most other genera, only the juvenile stagesexhibit such simple anatomy. Their mature, often-cal-cified thalli possess complex siphonal anatomy anddifferentiation depending on the location in the thal-lus. We obtained a nuclear ribosomal DNA phylogenyencompassing many genera in order to unravel theevolution of this complexity. Results pinpoint Caul-erpa as outgroup to a clade with all other genera in-cluded in this study. The first dichotomy separatesHalimeda from the remaining genera. Distinct gamet-angial anatomy defines these two principal clades.Within the remainder, Tydemania and its sister Flabel-lia are nearest neighbors to a clade containing Rhipo-cephalus, Udotea, Penicillus and Chlorodesmis. The latterthree genera are polyphyletic. Therefore, characterstates of thallus superstructure defining these generaappear to be homoplasies. Chlorodesmis represents acase of neoteny where the juvenile stage persists intoreproductive maturity. We will evaluate which mor-phological characters do change state in agreementwith the molecular phylogeny and can, therefore,serve as diagnostic characters for a more natural clas-sification.

114NITROGEN ASSIMILATION AND ALLOCA-TION STRATEGIES OF POLAR SEAWEEDSFROM DIFFERING NUTRIENT ENVIRON-MENTSKorb, R. E.1 & Gerard, V. A.2

1Wrigley Institute of Environmental Studies, Universityof Southern California, P.O. Box 5069, Avalon, Cali-fornia, 90704-5069 USA; 2Marine Sciences ResearchCentre, State University of New York, Stony Brook, NY,11794-5000 USA

Nitrogen assimilation and allocation strategies werecompared in polar macroalgae from environmentswith similar near-freezing temperatures and lowannual irradiance but differing dissolved inorganic ni-trogen (DIN) regimes. The antarctic endemic, Himan-tothallus grandifolius, experiences high nitrate con-centrations year-round and occasionally high, butvariable, ammonium levels. H. grandifolius cannotstore nitrogen or maintain growth under periods oflow N-supply. The arctic endemic, Laminaria solidun-gula, is exposed to seasonal fluctuations in DIN, withN-limitation occurring during the summer. L. solidun-gula showed “storage-specialist” characteristics of ni-trate uptake, with high Vmax allowing this species totake advantage of seasonally elevated nitrate concen-trations to accumulate large organic and inorganic N-reserves. H. grandifolius had a high Vmax for ammo-nium, allowing the alga to utilize pulses of this nutri-ent. In the presence of both DIN forms, nitrate up-take was significantly reduced in both species.Furthermore, H. grandifolius and L. solidungula dem-onstrated significantly reduced uptake and assimila-tion of nitrate during short-term and prolonged peri-ods of darkness, while ammonium uptake andassimilation were relatively unaffected by light. Al-though preferential uptake of ammonium, particu-larly in the dark, allows both species to conserve en-ergy in their cold, low-light environments, theantarctic species, which does not have the additionalproblem of N-limitation, showed stronger energy con-serving traits. Nitrogen assimilation characteristics ofthe arctic species appeared to balance energy conser-vation with the need to minimize N-limitation in anenvironment that alternates between low light andlow N availability.

115EXPRESSION PATTERNS OF THREE PUTA-TIVE SEXUAL-SPECIFIC GENES IN THE CEN-TRIC DIATOM THALASSIOSIRA WEISSFLOGIIKoumandou, V. & Armbrust, E. V.Marine Molecular Biotechnology Laboratory, School ofOceanography, University of Washington, Seattle, WA98195

An intriguing feature of the diatom life cycle is thatsexual reproduction not only generates genetic diver-sity but also controls cell size. Very little is known,however, about either the frequency or the potentialramifications of sexual events in field populations,due in large part to the difficulties associated with rec-ognizing sexual stages. Our approach has been to

PSA ABSTRACTS 39

identify genes involved in the diatom sexual cycle,with the goal of developing molecular probes to de-termine when and where sexual reproduction occurs.We are investigating the expression pattern of threegenes identified in a sexual reproduction screen. TheSig1, Sig2 and Sig3 genes comprise a gene family, andencode proteins with strong sequence homology toextracellular matrix proteins. We have hypothesizedthat the Sig proteins are necessary for sperm/egg rec-ognition. Using RT-PCR, we have shown that tran-scription of the Sig genes is highly upregulated dur-ing the early stages of the sexual cycle, before anymorphological changes are apparent. The threegenes show significant differences in the exact timingand levels of expression, suggesting different roles foreach member of the gene family. We are now employ-ing quantitative RT-PCR to study their relative tran-scription levels in more detail. We are also using anti-bodies made against a recombinant version of theSig2 protein to look at protein expression levels be-fore and after sexual induction, and to determinewhere the Sig2 protein localizes in the cell.

116PRELIMINARY EVALUATION OF THE BIO-REMEDIATION POTENTIAL OF PORPHYRA:PHOTOSYNTHETIC PRODUCTION BYBLADES AND CONCHOCELISKraemer, G. P.1 & Yarish, C.11Department of Environmental Sciences, Purchase Col-lege, State University of New York, Purchase, NY10577 USA; 2Department of Ecology and EvolutionaryBiology, University of Connecticut, Stamford, CT06901 USA

Given their rapid growth and nutrient assimilationrates, Porphyra spp. are good candidates for bioreme-diation. The production potential of two northeastU.S. Porphyra species currently in culture (P. purpureaand P. umbilicalis) was evaluated by measuring rates ofphotosynthesis (as O2 evolution) of samples grown at208 C. Gametophytes of P. umbilicalis photosynthe-sized at rates that were 80% higher than those of P.purpurea over 5–208 C at both sub-saturating and satu-rating irradiances (37 and 289 mmol photons m22

s21). Porphyra umbilicalis was both more efficient at lowirradiances (higher alpha) and had a higher Pmax thandid P. purpurea (23.0 vs. 15.6 mmol O2 g21 DW min21),suggesting that P. umbilicalis is a better choice for massculture where self-shading may be severe. The photo-synthesis-irradiance relationship for the Conchocelisstage of P. purpurea was also examined. Tufts of fila-ments, grown at 10, 15, and 208 C, were assayed atgrowth temperatures at irradiances ranging from 0–315 mmol photons m22 s21. Tufts were slightly moreproductive at 158 than at 108 C, but only ca. 4–6% asproductive as gametophytes. Maximum rates of netphotosynthesis were reduced by 66–74% in tufts

grown at 208 C (only about 2% of gametophytes). TheConchocelis stage, however, need not limit maricultureoperations; once Conchocelis cultures are established,they can be maintained over the long-term as readysources of spores for net seeding.

117NEW GENERA OF FRESHWATER CRYPTO-MONADS FROM COLORADOKugrens, P.1, Aguiar, R.1, Clay, B. L.2& Lee, R. E.31Department of Biology,Colorado State University, FortCollins, CO 80523USA; 2 Biology Department, Uni-versity of Massachusetts, Amherst, MA 01003 USAMassa of 3Department of Anatomy and Neurobiology,Colorado State University, Fort Collins, CO 80523USA

Electron microscopic examinations of numerous iso-lates from Colorado lakes and reservoirs have re-vealed several new genera and species. Based on thefurrow/gullet variations and the structure of the peri-plast, four new genera are proposed. These new gen-era and their characteristics are as follows. The firstgenus has a furrow without a gullet, and it has ovalperiplast plates. There are two chloroplasts per celland two nucleomorphs located anterior to the chloro-plasts in the periplastidial compartment. Pyrenoidsare lacking. Chloroplasts contain phycoerythrin 566.The second genus is similar in shape and structure toPlagioselmis, but it has small rectangular plates ratherthan hexagonal plates. There is one dorsal chloro-plast per cell, with a single stalked pyrenoid, which isnot traversed by thylakoids and associated with twostarch plates. The nucleomorph is posterior to thepyrenoid and is located between the nucleus andpyrenoid. Chloroplasts contain phycoerythrin 566.The third genus lacks a gullet and furrow and has aninner periplast sheet. Cells have two chloroplasts with-out pyrenoids, and the chloroplasts contain phyco-erythrin 566. The nucleomorphs are located in theanterior portion of the plastidial compartment. Thefourth genus is blue-green in color, it lacks a furrow/gullet, and the internal and surface periplast compo-nents consist of hexagonal plates. Cells have a largepyrenoid that protrudes ventrally into the cytoplasmand is traversed by numerous paired thylakoids. Thenucleomorph is situated lateral to the pyrenoid. Chlo-roplasts contain phycocyanin 645. This cryptomonadwas previously identified as Chroomonas pochmanni,and it is mixotrophic.

118GENETIC STRUCTURE VARIABILITY OFKELP ALARIA MARGINATA OVER SPACE ANDTIMEKusumo, H. T.1 & Druehl, L. D.2

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1Department of Ecology & Evolution University of Chi-cago, 1101 E. 57th St., Chicago, IL 60637;2Department of Biological Sciences, Simon Fraser Uni-versity, Burnaby, BC V5A 1S6, Canada & BamfieldMarine Station, Bamfield, BC V0R 1B0, Canada

The genetic variability of Alaria marginata Postels &Ruprecht was investigated spatially and seasonally us-ing the finger printing technique of amplified frag-ment length polymorphism (AFLP). Using 206 score-able bands generated by one primer pair, individualplants that were separated by as little as a few decime-ters to .100 km could be distinguished, and followedan isolation-by-distance model. Genetic similarityranged from 76% for patches (a few decimeters in di-ameter), to 71% for individual kelp stands (15 macross) and 67% for a group of stands separated by185 km. Greater genetic similarity of patches oc-curred at the wave-sheltered site than at wave-exposedsite. The influence of wave to genetic variability andthe ability to predict gene flow on small stretch ofbeach were discussed. In one stand, genetic similari-ties were markedly different between seasons. Thisseasonal pattern may be the result of different agegroups dominating the sampled stands over time. Thegenetic structure of A. marginata comprises local scale(patch and within stand) heterogeneity and largerscale (between stands) homogeneity.

119MOLECULAR ANALYSES OF LINEAR CHLO-ROPLAST PLASMIDS FROM ERNODESMISVERTICILLATALa Claire, J. W., II & Wang, J.Section of Molecular Cell & Developmental Biology,School of Biological Sciences (A6700), University ofTexas at Austin, TX 78712 USA

Ernodesmis verticillata contains novel, linear plasmid-like DNA molecules in its chloroplasts, whose func-tion remains unclear. Their molecular architecture isputatively a “hairpin,” wherein every molecule con-sists of a long inverted repeat folded back on itself.Thus, each molecule is composed of a terminal (telo-meric) domain, a central inverted repeat, and a“loop” domain. Cloning strategies have been devisedfor characterizing the terminal and loop regions,since they might contain landmark features like repli-cation origins. Polymerase chain reaction (PCR) wasused to amplify loop domains of native molecules,and ligation of the PCR products with commercialcloning vectors initially yielded 11 clones. So far, norecognizable sequences have turned up in the loopdomains of the molecules. Unlike what has been re-ported for most linear plasmids, we have been unableto verify that any proteins are associated with eitherthe 59- or 39-ends of the Ernodesmis plasmids. In fact,the 59-end of each molecule contains a terminal phos-

phate that is accessible to alkaline phosphatase andsubsequently to T4 polynucleotide kinase in vitro. It isalso possible to modify the 3’-end with terminal deox-ynucleotidyl transferase (TdT) for homopolymerictailing. Poly-(C) tailing of native molecules promotestheir annealing to poly-(G) tailed vectors, for cloningof the terminal domains. An initial library of 14 TdTclones (10 unique) indicates that short (11–28 bp) di-rect repeats occur near the termini of the plasmids.Shorter (4–6 bp) inverted repeats at the very endsmay lead to terminal foldbacks that might serve toprotect the termini.

120LIFE ON THE EDGE: STRESS SURVIVALADAPTATIONS IN SOUTHERN LIMIT MAC-ROCYSTIS PYRIFERA POPULATIONSLadah, L. B.Universidad Autonoma de Baja California, Institutode Investigaciones Oceanologicas Apdo. post # 453,Ensenada, Baja California, Mexico

In spite of subtropical temperatures often occurringat the Macrocystis pyrifera distributional southern limitin the Northern Hemisphere in Baja California, Mex-ico, the population has been successful at survivingand recovering from disturbance. To explore thephysiological characteristics of southern limit M. py-rifera, microscopic and macroscopic phases of south-ern limit plants were tested for stress tolerance andcompared to northern plant responses in three exper-iments. In spore development experiments, underconstant temperature and nitrate stress treatments,spores from the southern-limit population survivedhigher temperatures, had greater survivorship, andwere able to complete their life cycle at higher tem-peratures and lower nitrate concentrations thannorthern population spores. During stress-recoverytreatments, where all microscopic stages were testedfor recovery after stress shock exposure (temperature,nitrate and light stress), 96% of all haploid treatmentsshowed some regrowth during recovery; haploid sur-vival was not significantly affected by spore populationorigin, light, or nitrate. However, only 26% of diploidtreatments showed regrowth and diploid survival wassignificantly affected by spore population origin; onlythe southern limit spores recovered after stress treat-ment exposure. In juvenile transplant experiments,under all conditions, juvenile plants originating fromthe southern-limit had higher tissue nitrogen content,greater frond addition rates, and higher photosyn-thetic efficiency than northern plants, particularly athigher temperatures. The physiological differencesobserved for the southern limit plants versus thosefrom the north contributes to our understanding ofhow the southern limit plants can survive in an envi-ronment that might otherwise be considered extremefor the species.

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121ACCUMULATION OF DOMOIC ACID BY THECOASTAL DIATOM PSEUDO-NITZSCHIA MUL-TISERIES: A POSSIBLE COPPER COMPLEX-ATION STRATEGYLadizinsky, N. L. & Smith, G. J.Moss Landing Marine Labs, 8272 Moss LandingRoad, Moss Landing, CA 95039, USA

Domoic acid (DA) is a neurotoxic amino acid pro-duced by several members of the diatom genusPseudo-nitzschia. Trophic transfer of DA up the foodchain has been implicated in the deaths of 100’s ofmarine birds and marine mammals along the centralCalifornia Coast. The physiological function of DA inPseudo-nitzschia spp. has not been defined, althoughsome evidence indicates that elevated metal concen-trations can induce DA accumulation (Subba RAO etal., 1998, P.S.Z.N. Mar. Ecol. 19:31). Although Califor-nia coastal waters have experienced a decline in sev-eral heavy metals from 1977–1990, copper concentra-tions have increased by as much as 25% (Stephenson,M. D. & Leonard, G. H., 1994, Mar. Poll. Bull. 28:148).Many algae produce chelators, including amino acids,in response to toxic [Cu21] (Wu et al. 1998, J. Phycol.34: 113). Domoic acid, a tricarboxylic acid, has 4 func-tional groups that may readily form chelation com-plexes with transition metals like copper. Copper en-richment experiments indicate that while Cu21 istoxic to Pseudo-nitzschia multiseries at total [Cu] greaterthan 16.1mM (pCu 6.0), intracellular DA accumula-tion increases up to this point with no decline ingrowth rates relative to cultures grown in standard en-riched seawater. These data suggest that DA may beaccumulated by P. multiseries to mitigate the toxicity ofelevated [Cu21]. Chemiluminescence will be used toquantify the binding affinity (expressed as conditionalstability constants, Kc) of DA for Cu21. Defining theCu-DA dose response relationship in Pseudo-nitzschiacan facilitate prediction of future toxic bloom events.

122THE UBIQUITOUS PRESENCE OF CHLORO-PHYLL D IN RED ALGAE FROM THE MON-TEREY PENINSULALandráu, M. E. & Welschmeyer, N. A.Moss Landing Marine Laboratories, 8272 Moss Land-ing Road, Moss Landing, CA 95039 USA

The presence of chlorophyll d in red algae has been asubject of great controversy, however, only a few stud-ies have been devoted to this subject, and evidence forits existence has been inconsistent. Here we report onresults of a survey of 56 species of red macroalgaefrom central California, 3 species from Baja CaliforniaSur, Mexico, and 2 species from Cape Evans, Antarc-tica. Chlorophyll d was detected in 48 of the Califor-nia species, 1 of the Mexico species, and 1 of the Ant-

arctica species. Chlorophyll a/d ratio ranged from 6to 21123. The fraction of species of red algae contain-ing chlorophyll d was higher in samples collected inOctober (36 out of 36), than those collected in June(12 out of 29) or March (4 out of 22). Chlorophyll dwas not detected in any of the brown or green mac-roalgae analyzed. In vivo absorption spectra of Gelid-ium sp. were collected, and resolution of these spectraby fourth derivative resulted an absorption maximumat 687 nm due to chlorophyll a, and at 719 nm due tochlorophyll d. Extracted pigment of Gelidium sp. in90% acetone had an absorption maximum of 664 nm,and a smaller absorption peak at 692 nm. Fluores-cence emission and excitation spectra resulted in amaximum of 699 nm and 447 nm, respectively. Theemission peak wavelength of 699 and an absorptionpeak longer than that of chlorophyll a (699 nm com-pared to 664 nm) suggest chlorophyll d may serve as alight-harvesting pigment in photosynthesis.

123FLUID SHEAR-STIMULATED DINOFLAGEL-LATE BIOLUMINESCENCELatz, M. I.1 & Rohr, J.21Scripps Institution of Oceanography, University ofCalifornia San Diego, La Jolla, CA 92093 USA;2SPAWAR Systems Center, San Diego, CA 92152-5000 USA

Bioluminescence studies provide insight into theproperties of water motion that are stimulatory toflow-sensitive organisms such as dinoflagellates, themost common sources of near-surface oceanic biolu-minescence. Previous laboratory studies employingsteady flows have characterized the luminescent re-sponse of dinoflagellates in terms of shear stress. Inthe present study, computational and experimentalapproaches were used to investigate the contributionsof shear and acceleration to cells responding in a lam-inar converging flow field, where regions of high ac-celeration and shear are spatially separated. Flow-stimulated flashes by the dinoflagellates Lingulodiniumpolyedrum and Ceratocorys horrida were used as a near-instantaneous monitor of cell response. By combiningvideo analysis of flash trajectories with computationalmethods, the location of each stimulated cell was de-termined and flow parameters at that location werecalculated. Based on several criteria, shear stress wasconsidered the flow parameter most stimulatory tocells. For both dinoflagellates species and for all flowrates, essentially all cells responded downstream nearthe wall where shear stress levels were maximal, andlevels of acceleration and extensional stress were asmuch as two orders of magnitude less than locationsaway from the wall. Minimum shear stress levels at thecell positions were consistent with response thresh-olds based on previous studies. Bioluminescence is anexcellent tool for examining how organisms respond

42 PSA ABSTRACTS

to flow at the small temporal and spatial scales rele-vant to planktonic organisms.

124NOSTOCACEAN MACRO-MORPHOGENESISLazaroff, N.1,2 & Eichelberger, H. H.21Micro-Nostix, Vestal, NY 13850-1516 USA; 2Dept ofBiological Sciences, State University of New York atBinghamton, NY 13902-6000 USA

A poorly understood feature of nostocacean growthand development is the formation of ordered macro-scopic structures from microscopic cells, trichomes,and filaments. Using macro-photography, time-lapsemicro-cinematography, light and electron microscopyof Nostoc species in pure culture, it has been possibleto demonstrate how motility, adhesion and aggrega-tion of photo-induced hormogonia result in macro-morphogenesis of dendroid forms. Red-light inducedhormogonia from synchronized cultures aggregaterapidly on agar as tight flowing streams, in patterns re-sponsive to the direction and quality of incident light.Unlike the even textured cell surfaces of heterocys-tous filaments, the cell walls of swarming hormogoniaare covered with a striate mucoid layer containing piliattached to cells of adjacent hormogonia. During dif-ferentiation to an aseriate phase, cell wall fusionsoccur and a gelatinous matrix forms around theenlarging sub-globose cells. Liquid suspensions ofhormogonia aggregate in a solid mass following thenet centripetal movement of interlaced loops ofcurved hormogonia attached by adhesive pili. In dark-ness or dim white light, compressed hormogonial ag-gregates form erect tree-like (dendroid) macro-struc-tures by photo-tactic reversal of streaming motility.Hormogonia within the aggregates re-organize intostreams that push upward into the light, formingstructured, positively phototropic protuberances, sev-eral millimeters in length. Under weak illumination,the structures become branched with crowns of wav-ing hormogonia. The dendroid morphology is stabi-lized by deposit of gelatinous material derived fromsuccessive cycles of cell-filament development, libera-tion of heterocysts and formation of dormant cellsand trichomes.

125STEROLS AS BIOMARKERS IN GYMNODIN-IUM BREVE: DISTRIBUTION IN DINO-FLAGELLATESLeblond, J. D.1 & Chapman, P. J.21National Research Council Postdoctoral Associate;2US EPA (NHEERL), Gulf Ecology Division, 1 SabineIsland Dr., Gulf Breeze, FL 32561 USA

The sterol composition of marine microalgae hasbeen shown to be a chemotaxonomic property poten-tially of value in distinguishing members of different

algal classes. For example, members of the class Dino-phyceae display sterol compositions ranging from asfew as two (cholesterol and dinosterol in Alexandriumtamarense) to as many as twelve in certain Heterocapsaspecies. Certain of these are 4-methyl sterols rarelyfound in other classes of algae. The ability to use ste-rol biomarkers to distinguish certain dinoflagellatessuch as the toxic species Gymnodinium breve, responsi-ble for red tide events in the Gulf of Mexico, fromother species within the same class would be of con-siderable scientific and economic value. Gymnodiniumbreve has been shown by others to possess two princi-pal novel sterols, (24S)-4a-methylergosta-8(14), 22-dien-3b-ol (ED) and its 27-nor derivative (NED), notpreviously known to be present in other dinoflagel-lates. Characterization of free and esterified sterolsfrom laboratory cultures of G. breve and of samplesfrom a recent bloom in the Gulf of Mexico has con-firmed the predominance of these two sterols. Thishas prompted a study of the sterol signatures of morethan 30 dinoflagellates. ED and NED were shown alsoto be the primary sterols of the closely related dinoflagel-lates G. mikimotoi and G. galatheanum. They are alsofound as minor components of the more complex ste-rol profiles of other members of the Gymnodinium-Peri-dinium-Prorocentrum (GPP) taxonomic group. Themore widespread distribution of this sterol pattern isconsistent with the known close relationship betweenG. breve and G. mikimotoi.

126SPECIES PHYLOGENY OF COSMARIUM ANDSTAURASTRUM (DESMIDIACEAE) BASED ONRBCL SEQUENCESLee, O.-M.1, McCourt, R. M.2, Nam, M.1 & Karol,K. G.31Department of Biology, Kyonggi University, Suwon-city 442-760, Kyonggi-do, Korea; 2Department of Bot-any, Academy of Natural Sciences, 1900 BenjaminFranklin Parkway, Philadelphia, PA 19103; 3Departmentof Cell Biology and Molecular Genetics, H. J. PattersonHall, University of Maryland, College Park, MD20742

Cosmarium and Staurastrum are the two most diversegenera of placoderm desmids (Family Desmidiaceae),with approximately 1100 and 800 species, respectively.Phylogenetic analysis of relationships of species hasbeen extremely difficult. In a monograph of NorthAmerican placoderm desmids, Prescott et al. de-scribed early phylogenetic work that concluded Stau-rastrum to be polyphyletic and certainly polymorphic.Likewise, Cosmarium has also been viewed as polyphyl-etic, and a number of workers have proposed splittingthese genera. The classical view of West and Westgrouped species within each genus into two divisionsand 6–8 sections based on wall features and semicellshape. We sequenced rbcL from 18 species of Cosmar-

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ium (2 divisions, 7 sections) and 12 species of Stauras-trum (2 divisions and 7 sections) and performed aphylogenetic analysis (parsimony, maximum likeli-hood, bootstrap) using other placoderm desmids andZygnematales as outgroups. The results exhibit littlesupport for the monophyly of sections or divisions ofthe two genera. Furthermore, although there is sup-port for the monophyly of clades within each genus,there is also support for a separate clade containingspecies from both genera.

127MEASUREMENT OF MICROALGAL CELLVOLUME BY FLOW CYTOMETRYLeighfield, T. A. & Van Dolah, F. M.Marine Biotoxins Program, Center for Coastal Envi-ronmental Health and Biomolecular Research, NOAA,National Ocean Service, Charleston, SC 29412 USA

Single cell analysis by flow cytometry is a powerful toolthat has been employed to identify many differentcharacteristics of phytoplankton populations. Cell vol-ume is an important physiological component ofmany cellular processes. We have used a Coulter EP-ICS XL flow cytometer to measure cell volume in thespheroid dinoflagellate Amphidinium operculatum as afunction of forward scatter. Cell volume measure-ments of this alga were quantified as equivalent spher-ical diameters from a standard curve obtained with la-tex beads of known diameter. This parameter wasused to monitor cell diameter throughout the cell di-vision cycle. In log phase cultures, A. operculatumshowed increasing cell volumes throughout the lightphase and a maximum cell volume concurrent withthe onset of cell division late in the light phase. Themaximum equivalent spherical diameter measured 14mm, while the minimum equivalent spherical diame-ter was 10 mm that occurred late in the dark phase.Stationary phase cultures of A. operculatum did not ex-hibit oscillating cell volumes throughout the diel cy-cle. Chemical inhibition of the cell cycle using 100mM olomoucine diminished cell volume changes dur-ing the light phase. These results suggest a couplingof size control to the cell division cycle.

128IDENTIFICATION OF A CYCLIC AMP-DEPEN-DENT PROTEIN KINASE IN THE DINO-FLAGELLATE AMPHIDINIUM OPERCULATUMLeighfield, T. A. & Van Dolah, F. M.Marine Biotoxins Program, Center for Coastal Envi-ronmental Health and Biomolecular Research, NOAA,National Ocean Service, Charleston, SC 29412 USA

Cyclic AMP is an important signaling molecule inboth prokaryotes and eukaryotes. In eukaryotes, the

action of cyclic AMP is mediated by cyclic AMP-depen-dent protein kinase (PKA). Efforts to identify PKA indinoflagellates have met with mixed success in previ-ous studies. In Amphidinium operculatum, we have iden-tified the presence of cAMP, and observed cell cycleinhibition by the cAMP pathway inhibitor, isobutylmethylxanthine, suggesting the presence of a eukary-otic cAMP pathway. However, crude lysates of A. oper-culatum failed to show in vitro kinase activity towardkemptide, a specific substrate of mammalian PKA.This may reflect the presence of unidentified low mo-lecular weight inhibitors, because when cell lysateswere fractionated by gel filtration chromatography,cAMP dependent kinase activity was identified. Themolecular weight of this PKA was 66 kDa, muchsmaller than bovine PKA (250 kDa), but similar tothat reported in the diatom Cylindrotheca (78 kDa).Current work is focusing on characterization of sub-unit structure of the PKA of A. operculatum, as com-pared with bovine PKA.

129RELATIVE TOLERANCE OF MAT-FORMINGALGAE TO COPPER AND ITS IMPLICA-TIONSLembi, C. A.Department of Botany and Plant Pathology, PurdueUniversity, W. Lafayette, IN 47907 USA

The major method for algae control in the U.S. is theapplication of copper. Certain groups of phytoplank-ton, such as the green algae, are known to be moretolerant to copper than groups such as the cyanobac-teria. Through experience, commercial applicatorssuggest that mat-forming algae also differ in their sus-ceptibility to copper, but to this point, data to supportthese observations have not been available. Labora-tory studies in which unialgal cultures of mat-formingalgae were exposed to a range of copper concentra-tions show a clear progression in copper tolerance.The EC50 values (concentration of copper in mg CuL21 that results in 50% reduction of biomass) wereless than 0.003 (Spirogyra, Oedogonium), approximately0.050 (Hydrodictyon, Pithophora, Rhizoclonium), andgreater than 0.200 (Oscillatoria). These data are im-portant to us in the midwest because Oscillatoria is be-coming a more frequent component of mat-formingalgae infestations. The Oscillatoria infestations arecaused by at least five different species, each of whichis very tolerant to copper. Circumstantial evidencesuggests that the increasing frequency of this mat-forming cyanobacterium is due to elimination ofmore sensitive genera (such as Spirogyra or Rhizoclo-nium) with heavy copper dosing. In addition to con-cerns often expressed about copper use, such asbuildup in the sediments, toxicity to invertebrates,and possible (although not well verified) resistance ofcyanobacteria, another compelling reason to seek al-

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ternative approaches to copper is the buildup of cop-per-tolerant mat-forming algae.

130PHENOLOGY OF SCINAIA LATIFRONS (NEM-ALIALES; RHODOPHYTA) IN THE SOUTH-WESTERN GULF OF CALIFORNIA, MEXICOLeón-Cisneros, K. & Riosmena-Rodriguez, R.Herbario Ficológico, Mar. Biol. Dept., UABCS, Ap.Postal 19-B, La Paz B.C.S. 23080 México

Scinaia latifrons Howe is one of the main species inrhodolith beds between 30 and 90 feet; however, littleknown about the morphological changes of this spe-cies. Consequently, we investigated the phenologicalchanges of the species at San Lorenzo channel fromDecember 1998 to December 1999 (based on bi-weekly sampling during the first 6 months andmonthly sampling during the last part of the study).The gametophyte phase of the species is present fromDecember to late May and the sporophyte potentiallyis present the rest of the year. The peak of the devel-opment occurs in April and reproduction occurs insmall size plants with two cohorts in the period. Thisspecies presents an allometric growth pattern due tothe lack of correlation between size and width of theplant or branching patterns. Our data suggest thattemperature and light control the development of theplant. Furthermore, we found the spermatagonialstructure in the same thallus as the female/carpo-sporophyte plant indicating that this species is mo-noeious (contrary to what was considered previously).This suggests that some taxonomic problems arepresent in this species in relation with S. cottoni.

131PHYLOGENETIC AND TAXONOMIC REAS-SESSMENT OF THE DELESSERIACEAE (CER-AMIALES, RHODOPHYTA) BASED ON TWOMOLECULAR DATA SETSLin, S. M.1, Fredericq, S.1, & Hommersand, M.21Department of Biology, University of Louisiana atLafayette, Lafayette LA 70504 USA; 2Department ofBiology, University of North Carolina at Chapel Hill,Chapel Hill NC 27599 USA

The current system of classification of the Delesseri-aceae rests largely on Kylin’s treatment which encom-pass the subfamilies Delesserioideae with five‘Groups’ and Nitophylloideae with six ‘Groups’. Inthis study we test the Kylin system based on phyloge-netic analyses inferred from two molecular data setsand morphological evidence. A total of 145 delesseri-acean taxa worldwide were sequenced for chloroplast-encoded rbcL, and 82 taxa for the nuclear-encodedlarge subunit ribosomal RNA gene (LSU). Threelarge clades are identified in the combined data sets,

one of which corresponds to the Delesserioideae, oneto a narrowly circumscribed Nitophylloideae, and thethird to a new subfamily comprising the remainder ofthe Nitophylloideae sensu Kylin. Belonging to theDelesserioideae are an expanded Hemineura groupthat includes Hemineura, Patulophycus, Marionella,Laingia, Botryocarpa and possibly Pseudophycodrys, aCaloglossa group, a Hypoglossum group that includesHypoglossum, Branchioglossum, Bartoniella, Zellera, Phity-morphora, and Chauviniella, a Delesseria group withDelesseria, Membranoptera and possibly Grinnellia (butnot Apoglossum) and most southern hemispherespecies of Delesseria which are properly placed in Para-glossum J. Agardh 1898. The revised Nitophylloideaecontains Nitophyllum, Valeriemaya, Polyneuropsis, Caloni-tophyllum and also Martensia and Opephyllum. The un-named subfamily includes the Phycodrys group withPhycodrys and Polyneura, the Cryptopleura group withspecies placed in Cryptopleura, Hymenena, Acrosoriumand Botryoglossum, the Myriogrammeae with Myrio-gramme and Haraldiophyllum, and the Schizoserideaewith Schizoseris, Neuroglossum, Drachiella, Abroteia, andSouth American species of Platyclinia. This researchpromotes the correlation of molecular and morpho-logical phylogenies with biogeographic hypothesesfor the family.

132PHYLOGENY OF THE EUGLENOPHYTES:ANALYSIS USING SSU RDNA AND ULTRA-STRUCTURAL CHARACTERSLinton, E. W. & Triemer, R. E.Division of Life Science, Rutgers University, Piscat-away, NJ 08854 USA

The use of both molecular and morphological data todetermine relationships among the euglenoids is vitalfor a complete understanding of their phylogeny, andthe development of an accurate taxonomy. Analysesof the SSU (18S) rDNA from 12 euglenoid generahave resulted in tree topologies that are in agreementwith many defining morphological characters. Theeuglenoid lineage is formed by phagotrophic eugle-noids at its base, followed by the divergence of pho-totrophs that in-turn gave rise to osmotrophs. Thephotosynthetic lineage is anchored by euglenoidswith two emergent flagella, Eutreptia and Eutreptiella,while the remainder of the lineage is composed of eu-glenoids with a single emergent flagellum. Among thephotosynthetic euglenoids with a single emergent fla-gellum those that secrete mucilaginous stalks, Colacium,or form a lorica, Trachelomonas and Strombomonas, areclosely associated. The remaining photosynthetic gen-era Euglena, Phacus, and Lepocinclis are intermixedwith each other and the osmotrophic genera Astasia,and Khawkinea. Hence, they are not monophyletic,sensu Hennig. To reinforce molecular phylogenies, arobust morphological character database is necessary.For taxa with complex internal structures complete

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serial reconstruction is required. Serial reconstruc-tion of the flagellar and feeding apparatuses in Ploeo-tia costata illustrate this necessity. Originally describedas having both an MTR (Type I) and a Type II feedingapparatus, reconstruction has shown P. costata to havea single, Type II, feeding apparatus. Moreover, theType II now appears to be an autapomorphy for Ploeo-tia species, while euglenoid feeding apparatuses, intoto, appear to form a continuum of structural types.

133PHENOLOGY OF PORPHYRA PENDULA(BANGIALES; RHODOPHYTA) IN THESOUTHWESTERN GULF OF CALIFORNIA,MEXICOLópez-Vivas, J. M. & Riosmena-Rodriguez, R.Herbario Ficológico, Mar. Biol. Dept., UABCS, Ap.Postal 19-B, La Paz B.C.S. 23080 México

Porphyra pendula Dawson is an endemic species of themid-intertidial zone in the Gulf of California. Basedon surveys from the Phycological Herbarium of UABCSsince 1994, we found an extensive population of thisspecies in Punta Coyote, south of La Paz. Here, we as-sess the phenology of the gametophyte phase from De-cember of 1998 to June of 1999 with visits every 2weeks. Our results show significant temporal and spa-tial changes in length and width of the plant, withsome quadrants displaying two peaks in development(January and March) and other quadrants with apeak only in January. A significant correlation existedbetween length and width of the blade and is linkedwith plant maturation, observations which strongly sup-port the isometric growth rate of the species. No dif-ferences between exposed and protected areas wereobserved suggesting stronger differences betweenquadrants. Differences plants in length and in colorexisted between male and female plants; the maleswere smaller and yellow and females/carposporo-phyte were larger and red-purple. Most of the thalliwere reproducing during the study, with a greaterproportion of females than males (ca. 2:1). Our re-sults suggest that the morphological changes in thisspecies may be related with temperature and daylength.

134GRAZER-INDUCED DEFENSE IN SCENEDES-MUS OBLIQUUS (CHLOROPHYCAEA)Lürling, M.Department of Food Web Studies, Center for Limnology,Netherlands Institute for Ecology, Nieuwersluis 3631AC 6, The Netherlands

The non-spiny Scenedesmus obliquus may express con-siderable phenotypic plasticity in response to changes

in their environment. When exposed to chemicals re-leased from the grazer Ceriodaphnia, unicellular S.obliquus populations were rapidly transformed into co-lonial ones. The morphological response appearedstrongly correlated with the amount of algae grazedupon by the Ceriodaphnia. The induced S. obliquus col-onies were protected against grazing, as were largespined Scenedesmus, whereas unicellular S. obliquus andspined Scenedesmus remained vulnerable to grazing byCeriodaphnia. Growth rates of unicellular and induced-colonial S. obliquus populations were identical. How-ever, sinking rates were significantly higher for the in-duced-colonial S. obliquus. Hence, the phenomenonof grazer-induced colony formation in S. obliquus canbe interpreted as an inducible defense at the expenseof higher sinking losses.

135THE TYPE SPECIES OF CERAMIUM (RHODO-PHYTA), CERAMIUM VIRGATUM ROTH: TYPI-FICATION AND PHYLOGENYMaggs, C. A., McIvor, L. M., Evan, C. M. &Stanhope, M. J.School of Biology and Biochemistry, Queen’s Universityof Belfast, Belfast BT9 7BL, United Kingdom

The type species of Ceramium is Ceramium virgatumRoth (1797, Cat. Bot I: 148, pl. VIII, fig. 1). This hasbeen treated as a probable synonym of Ceramium nod-ulosum (Lightfoot) Ducluzeau, one of the species for-merly confused under the illegitimate name Ceramiumrubrum (Hudson) C. Agardh. However, in 1996 Silvashowed that C. nodulosum (Lightfoot) Ducluzeau is alater homonym of C. nodulosum de Candolle 1805, andadvocated conserving C. rubrum with a neotype. As analternative to this, we investigated whether the nameC. virgatum might be available for this species. The lec-totype of C. virgatum is Roth’s illustration of a much-branched, fully corticate, Ceramium specimen fromEckwarden, North Sea, which could represent anymember of the ‘C. rubrum’ group. We obtained mate-rial resembling Roth’s, from the North Sea island ofHelgoland, as a potential epitype. Its rbcL sequencewas aligned with sequences of all C. rubrum-like spe-cies in the British Isles, i.e. C. secundatum, C. botryocar-pum, C. pallidum and ‘C. nodulosum’. The Helgolandmaterial was clearly conspecific with ‘C. nodulosum’from Ireland (0.08% divergence). We therefore sug-gest that the name C. virgatum Roth should be em-ployed for this species. Phylogenetic analyses of thesesequences aligned with various representatives of thetribe Ceramieae, placed the North Atlantic C. rubrum-like species in two well-supported clades. In one ofthese, C. virgatum is basal to C. secundatum and C. botry-ocarpum. The other clade consists of C. pallidum and apartly ecorticate species resembling C. diaphanum.

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136INTER-FAMILY USE OF MICROSATELLITEMARKERS IN LAMINARIALES: THE EXPERI-ENCE BETWEEN LAMINARIA DIGITATA ANDLESSONIA SPP.Martínez, E. A.1, Cardenas, L.1, Figueroa, C.1,Vidal, R.1, & Billot, C.21Departamento de Ecologia, Facultad de Ciencias Bio-logicas, Pontificia Universidad Catolica de Chile,Casilla 114-D, Santiago, Chile; 2Universidade do Al-garve Campus de Gambelas P-8000 FARO, Portugal

Among the co-dominant molecular markers, micro-satellite loci have a number of advantages in popula-tion genetic studies. However, the different methodsto hunt these markers are expensive, time consuming,and they require sophisticated laboratory equipment.Using in one species the microsatellites primers origi-nally described for another one saves time and re-duces costs. Examples in the literature revealed thatmicrosatellites described for Gracilaria gracilis fromFrance have not worked for other members of theGracilariales. The results were not very promising, atleast for Gracilaria chilensis from Chile. In this study, anumber of microsatellite loci described for Laminariadigitata (Laminariaceae) from France were amplifiedand sequenced in two Lessonia (Lessoniaceae) speciesfrom Chile. Preliminary results show a partial conser-vation of both, flanking and tandem repeat regions.Some polymorphism has also been detected in Lesso-nia spp. The higher molecular affinity (conservationof primer sites) observed in species belonging to dif-ferent families of brown algae, respect to that ob-served among species of the same genus in the redalgae, is surprising. Such a result is strikingly counter-intuitive when observing the morphological disparityamong the Laminariales, respect to the similarity ob-served in the Gracilariales. It also reminds one of anearlier discussion by Gary Saunders about “When afamily is not a family”.

137PLASTID FATTY ACID BIOSYNTHESIS INTHE DIATOMS NITZSCHIA ALBA AND NITZS-CHIA LAEVISMcGinnis, K. M. & Sommerfeld, M. R.Department of Plant Biology, Arizona State University,Tempe, AZ 85287 USA

The role of the plastid in fatty acid biosynthesis in thenon-photosynthetic diatom Nitzschia alba was studiedand compared to that in the photosynthetic, closelyrelated Nitzschia laevis. Transmission electron micros-copy was used to analyze structural features of theplastid that may be relevant to biochemical function.Typical of a photosynthetic diatom, N. laevis had achloroplast envelope composed of four membranes,

and had abundant chloroplast ribosomes. The leuco-plast of N. alba also had a multi-membrane envelope,chloroplast ribosomes, and a genome that encodesplastid specific proteins. This suggested that the plas-tid of N. alba may still possess the biochemical func-tions of the chloroplast, aside from photosynthesis.To determine whether plastidial fatty acid biosynthe-sis occurred in N. alba, the response of the two dia-toms to the compound thiolactomycin was compared.Thiolactomycin has been shown to effect keto-acyl-ACP-synthases, and specifically inhibits the plastidialfatty acid biosynthetic pathway. While growth of N.alba was not impacted by thiolactomycin as in N. lae-vis, neutral lipid accumulation and fatty acid composi-tion was impacted by thiolactomycin in both organ-isms. These findings suggest that the plastidial fattyacid biosynthetic pathway does exist in the leucoplastof N. alba, although it lacks photosynthetic capacity.

138SYSTEMATICS AND PHYLOGEOGRAPHY OFTHE INVASIVE RED ALGA, POLYSIPHONIAHARVEYIMcIvor, L. M.1, Maggs, C. A.1, & Stanhope, M. J.21School of Biology and Biochemistry, Department of Sci-ence and Agriculture, Medical Biology Center, TheQueens University of Belfast, Belfast, United Kingdom;2SmithKline Beecham Pharmaceuticals, South College-ville Road, UP1345, Collegeville, PA 19426 USA

Polysiphonia harveyi Bailey was first described fromConnecticut in 1848 and morphologically similar spe-cies, such as P. japonica and P. strictissima, have subse-quently been described many times from different lo-calities such as Japan and New Zealand, placing thetaxonomy and nomenclature of this morphologicallyvariable species in confusion. Polysiphonia harveyi is re-garded as an alien in the British Isles and the north-eastern North Atlantic and is reported to be spread-ing rapidly. The first confirmed collection of P. harveyifrom the British Isles was in 1908; the source of theBritish introduction remains unknown. In conjunc-tion with breeding data, rbcL sequences for samples ofP. harveyi, P. strictissima, P. japonica and P. akkeshiensiscollected from New Zealand, Atlantic and PacificNorth America, Japan and Europe, reveal that P. har-veyi, P. japonica and P. akkeshiensis constitute a singlebiological species. The correct name for this is P. har-veyi, whilst P. strictissima from New Zealand is a siblingspecies, distinct from P. harveyi. The center of geneticdiversity of P. harveyi is in Japan. The original sourceof the introduced P. harveyi in the British Isles, Eu-rope and Nova Scotia appears to be Hokkaido, Japan.Separate introductions from a single source popula-tion into New Zealand and Pacific and Atlantic NorthAmerica from Honshu, Japan, apparently have oc-curred.

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139THE TYCHOPELAGIC DIATOM, PARALIASULCATA, AS PALEOINDICATOR SPECIES INCOASTAL MARINE ENVIRONMENTSMcQuoid, M. R.Department of Marine Botany, Göteborg University,Box 461, SE-405 30 Göteborg, Sweden

Paralia sulcata is a diatom commonly found in boththe plankton and benthos of coastal environments.This species is heavily silicified and, thus preserveswell in sedimentary records making it a potentiallyuseful paleoindicator species. However, its tychope-lagic nature and its association with a wide range ofenvironmental conditions have made detailed paleo-ecological interpretations complicated. High-resolu-tion sediment records from coastal fjords in both Can-ada and Sweden show variations in the abundanceand morphology of P. sulcata that provide evidence ofchanges in benthic habitat distribution and surfacewater properties in the fjords on timescales of decadesto centuries. These studies suggest that P. sulcata canbe an important paleoindicator species when inter-pretations are made in the context of its complexecology.

140PHYLOGENY OF THE GENUS CHLOROCOC-CUM: A STUDY OF 18S AND 26S rRNA GENESEQUENCESMichalopulos, J. U., Buchheim, J. A. & Buchheim,M. A.Department of Biological Science, The University ofTulsa, 600 South College Avenue, Tulsa, OK 74104USA

Phylogenetic studies of 18S rRNA gene sequence datasupport an alliance of the green algal genus, Chlorococ-cum, with other chlamydomonadalean taxa that pro-duce walled, motile stages. Moreover, these phyloge-netic studies indicate that Chlorococcum is notmonophyletic, but rather falls into two distinct lin-eages. However, these molecular phylogenetic studieswere based on only a few taxa in a genus that exhibitsmarked habitat diversity. In particular, numerous spe-cies of Chlorococcum currently in the UTEX collectionhave been isolated from naturally acidic environ-ments. Except for a few groups (e.g., desmids), acidicenvironments are not generally regarded as niches forwidespread exploitation by green algae. A new investi-gation of diversity among species of Chlorococcum in-cluded broader taxon and data sampling schemes. Se-quence data from both the nuclear-encoded 18S and26S rRNA genes were collected from 17 differentUTEX and SAG isolates of Chlorococcum. In addition,controlled growth experiments at varying acidity (pH5.0, 6.0, and 8.0) were conducted. Results of these in-

vestigations suggest that the Chlorococcum-like mor-phology has evolved in at least three lineages. Further-more, these data suggest that the ability to growoptimally at low pH has independently evolved in sev-eral lineages.

141COMPARING RESPIRATORY (ETS) ACTIV-ITY OF BACTERIA ATTACHED TO PHY-TOPLANKTON AND FREELY SUSPENDED INSURROUNDING SEAWATERMilbrandt, E. C. & Shapiro, L. S.Oregon Institute of Marine Biology, P.O. Box 5389,Charleston, OR 97420 USA

We conducted investigated respiratory (ETS) activityof bacteria attached to phytoplankton and living freein surrounding seawater collected from coastal watersat Charleston, Oregon, USA. We hypothesized thatthe surface of a phytoplankton cell provides a habitatthat permits enhanced metabolic activity in attachedbacteria. In order to test this hypothesis, the numberof bacteria that reduce 5-Cyano-2,3-di-tolyl tetrazo-lium chloride (CTC) were compared to the totalnumber of bacteria, assessed by the nucleic acid stain,49,6-diamidino-2-phenylindole (DAPI). Two-hour incu-bations with the CTC dye and subsequent staining al-lowed for direct viewing of the position and the num-ber of ETS active versus inactive bacteria in eachsample. We found that the percentage of active bacte-ria attached to the phytoplankton cells’ surface (42%)was 10 times that of bacteria freely suspended in thesurrounding seawater (4%). Previous investigations ofETS activity of freely suspended bacteria found that1% to 8% are actively respiring while non-living parti-cle associated bacteria showed that 20 to 35% of bac-teria are actively respiring. Our results suggest thatbacteria in coastal waters are substrate limited, andthe extracellular products of photosynthesis may bemore important than is generally realized. The sur-faces of phytoplankton cell surfaces may provide habi-tat and substrates for a disproportionate share of bac-terial production in coastal waters.

142SEASONAL GROWTH AND NUTRIENT ECO-PHYSIOLOGY OF ECKLONIA RADIATA FROMDOUBTFUL SOUND, FIORDLAND, NEWZEALANDMiller, S. M.1, Hurd, C. L1 & Wing, S.21Department of Botany, University of Otago, Dunedin,New Zealand; 2Department of Marine Science, Univer-sity of Otago, Dunedin, New Zealand

The kelp, Ecklonia radiata, dominates the sublittoralzone within the Doubtful Sound complex. DoubtfulSound is one of a series of fourteen fiords indenting

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the southwestern coast of the South Island, NewZealand. A feature of these fiords is the freshwaterlayer that resides atop the salt water, creating aunique marine environment. Mature sporophyteswere collected from three sites (two outer sites to-wards the coastline and one site within the fiord) overa fourteen-month period (October 1998 to December1999). Growth rates, measured using the hole punchtechnique, were greatest in spring at all three sites.The nutrient eco-physiology of mature E. radiata wasinvestigated by measuring inorganic nitrogen (NO23

and NH14) uptake rates at eight concentrations (2–64mM). Soluble tissue nitrogen (NO23 and NH14) andtissue carbon:nitrogen (C:N) ratios were also deter-mined. At all sites, E. radiata showed higher uptakerates for ammonium than for nitrate. In winter, solu-ble tissue nitrogen was lower at the two outer sitescompared to the inner site, while in summer, levels atall sites were similar but had decreased from the win-ter values. C:N ratios greater than 20 were observed atall sites, increasing in summer to a peak in autumn,suggesting E. radiata may be nitrogen limited, particu-larly in late summer. Environmental parameters (pho-ton flux density, water temperature, rainfall andwind) were measured, as was sea water velocityaround the primary blade of E. radiata, and multivari-ate correlations used to determine which (if any) en-vironmental parameter exerted greatest influence oneco-physiological parameters accessed.

143THE EVOLUTION OF THERMOTOLERANCEIN HOT SPRING CYANOBACTERIA OF THEGENUS SYNECHOCOCCUSMiller, S. R.1 & Castenholz, R. W.21M/S 239-4, National Aeronautics and Space Admin-istration, Ames Research Center, Moffett Field, CA94035 USA; 2Department of Biology, University of Ore-gon, Eugene, OR 97403 USA

The extension of ecological tolerance limits may bean important mechanism by which microorganismsadapt to novel environments, but it may come at theevolutionary cost of reduced performance under an-cestral conditions. We combined a comparative physi-ological approach with phylogenetic analyses to studythe evolution of thermotolerance in hot spring cyano-bacteria of the genus Synechococcus. Among the twentylaboratory clones of Synechococcus isolated from collec-tions made along an Oregon hot spring thermal gra-dient, four different 16S ribosomal RNA gene se-quences were identified. Phylogenies constructedusing these sequence data indicated that the cloneswere polyphyletic but also that three of the four se-quence groups formed a clade. Differences in ther-motolerance were observed for clones with different16S rRNA gene sequences, and comparison of thesephysiological differences within a phylogenetic frame-

work provided evidence that more thermotolerant lin-eages of Synechococcus evolved from less thermotoler-ant ancestors. The extension of the thermal limit inthese bacteria was correlated with a reduction in ther-mal niche breadth, which may have implications forthe geographic distributions of these organisms. Thisstudy illustrates the utility of using phylogenetic com-parative methods to investigate how evolutionary pro-cesses have shaped historical patterns of ecological di-versification in microorganisms.

144RELATING PHYTOPLANKTON BIOMASS ANDPRODUCTION TO EPISODIC PHYSICALFORCING IN SOUTHEASTERN LAKE MICHI-GANMillie, D. F.1, Fahnenstiel, G. L.2, Lohrenz, S. E.3,& Schofield, O.41USDA-ARS., c/o Mote Marine Laboratory, 1600 KenThompson Parkway, Sarasota, FL 34236 USA;2NOAA-GLERL, Lake Michigan Field Station,Muskegon, MI 49441USA; 3Department of MarineScience, University of Southern Mississippi, StennisSpace Center, MS 39529 USA; 4Institute of Marine &Coastal Sciences, Rutgers University, New Brunswick,NJ 08901 USA

Spatial and temporal dynamics in phytoplankton re-flect of the combined effects of the physical andchemical environments and associated biological re-sponses. Although alterations in phytoplankton arewell-documented for a variety of lentic waters, the ex-act linkages between environmental forcing and phy-toplankton assemblages remain poorly understood(particularly for coastal systems). A recurrent sedi-ment resuspension event occurs every late winter/early spring in southeastern Lake Michigan, often ex-tending greater than ten km in width and 300 km inlength. Inherently, such a large-scale and dramaticphysical process would be thought to dramatically in-fluence phytoplankton assemblages; however, link-ages between the turbidity plume and phytoplanktonassemblages have been postulated, but never verified.As such, the episodic nature of the plume provided anopportunity to examine the effects of a short-termphysical forcing event on coastal phytoplankton in re-lation to more persistent, seasonal meteorologicalforcing. Lake phytoplankton assemblages within andoutside of the RCP were examined during the springisothermal period from 1998 to 2000. Here, we de-scribe results from the 1998 and 1999 field seasonscharacterizing the distribution of phytoplankton bio-mass and composition within and adjacent to the RCPand their relationship to particulate and dissolved con-stituents. In addition, the spatial and temporal pat-terns in production and photosynthetic characteris-tics of the phytoplankton community are examined.

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145ALGAL BIOREMEDIATION OF THE BERKE-LEY PIT LAKEMitman, G. G.Department of Biological Sciences-Montana Tech ofThe University of Montana

Ongoing research is unraveling the intricacies of themicrobial ecology of the Berkeley Pit Lake System,with ever increasing information becoming availableregarding the diversity of Algae, Protistans, Fungi andBacteria that inhabit this mine waste site. Defining thebaseline community structure has been the first stepnot only toward understanding the interactions of thedifferent groups of organisms, but also toward assess-ing any improvement in biodiversity within the bioticcommunity. Now that this first step has begun, someof these extremophiles, specifically algae, that havebeen isolated from the Berkeley Pit Lake System arebeing used as a potential solution for bioremediation.The specific objectives of this research are fivefold: 1)To evaluate the bioremediative potential of our fourmost rapidly growing species: (Chromulina freiburgensisDofl., Chlorella ellipsoidea Gerneck, Chlorella vulgarisBeyerinck and Chlamydomonas acidophilla Negoro) inBerkeley Pit Lake System Water with the additions ofNaNO3 and NaPO4 by using an experimental matrix.This matrix will be used to estimate the minimum nu-trient concentrations that would be necessary toachieve the maximum growth of algae and maximumbioremediation of the Berkeley Pit Lake System. 2)To determine which combination of nutrients willstimulate growth of the best bioremediator of ourfour isolated species in natural Berkeley Pit Lake Sys-tem waters. In other words, what nutrient combina-tion will give the best bioremediator a competitiveedge over the other species. If time permits, differentspecies may be grown in combination to determine ifthere are synergistic effects (protocooperation) be-tween/among species. 3) To determine a tempera-ture profile for these four species in order to deter-mine their optimal growth temperature in BerkeleyPit Lake System water. 4) To continue to isolate or-ganisms from the Berkeley Pit Lake System and deter-mine their bioremediative potential. 5) Monitor algaland bacterial counts from a profile of Pit Lake Systemwaters. The results to date will be presented for thisconference.

146DIVERSITY AMONG TETRASPORALEAN TAXA:EVIDENCE FROM ULTRASTRUCTURE ANDMOLECULESMoreland, A., Buchheim, M. A. & Buchheim, J. A.Department of Biological Science, The University ofTulsa, 600 South College Avenue, Tulsa, OK 74104USA

Recent phylogenetic studies of tetrasporalean exem-plars using 18S rDNA revealed the extent of diversityamong taxa in this non-monophyletic group (Bootonet al. 1998). In particular, two distinct tetrasporaleanlineages were identified; one group allied with chlamy-domonadalean taxa and the other group comprisingtaxa now placed in a separate order, the Chaetopeltid-ales. Using these observations as a framework, a newinvestigation of diversity among a broader samplingof putative tetrasporalean genera (e.g. Asterococcus,Chloranomala, Chlorophysema, Gloeocystis, Gloeodendron,Palmella, Paulschulzia, Physocytium, Schizochlamys andTetraspora) was undertaken. Phylogenetic studies of both18S and 26S rDNA were compared with ultrastructuralinvestigations of vegetative cells. Molecular phyloge-netic analyses corroborate the earlier 18S rDNA results,but also reveal additional diversity. The new data raisedoubts regarding the monophyly of two genera, Palmellaand Tetraspora. The new data also link two enigmaticgreen algal genera, Physocytium and Heterochlamydomo-nas, in a long-branch lineage within the Chlamy-domonadales. Another enigmatic genus, Schizochlamys,is allied with Bracteacoccus in the Sphaeropleales. Lastly,Chloranomala is resolved as an ally of Paulschulzia, Tet-raspora sp., and the green flagellate, Lobomonas. Com-parison of pyrenoid ultrastructure generally supportsthe molecular phylogenetic analyses, suggesting thatthis non-molecular character will be a useful markerfor broad phylogenetic studies of chlamydomonad-alean taxa. (Supported by NSF grant, DEB 9726588)

147CHEMICALLY INDUCED ECDYSIS AND ISO-LATION OF NUCLEI FROM THE DINO-FLAGELLATES GONYAULAX POLYEDRA ANDGONYAULAX TAMERENSISMorris, R. L., & Rizzo, P. J.Department of Biology, Texas A & M University, Col-lege Station, TX 77843 USA

Armored dinoflagellates such as Gonyaulax sp. are notgood candidates for isolation of intact clean nuclei,due to difficulty in breaking the cells. Previously, isola-tion of nuclei from Gonyaulax was achieved using vig-orous cell disruption by ultrasonication (Rizzo &Hastings, unpublished observations). A detergentmethod for production of spheroplasts from Gon-yaulax was published some time ago (Adamich &Sweeney, 1976), but was not reproducible (Rizzo &Hastings, Morris & Rizzo, unpublished observations).We describe here a modification of the method de-scribed by Adamich & Sweeney that is highly repro-ducible. Ecdysis and production of intact dinoflagel-late spheroplasts with a yield of virtually 100% within5 minutes, has been achieved through the use of an-ionic and nonionic detergents in hypotonic buffers.This method of ecdysis followed by a gentle sphero-

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plast breakage in a hypotonic buffer allowed therelease of nuclei for later biochemical analysis withminimal damage or breakage. The nuclei are subse-quently purified by centrifugation in a Ficoll discon-tinuous gradient.

148STRUCTURAL AND SEQUENCE SIGNA-TURES OF NUCLEAR SSU RRNA DEFINETAXONOMIC LEVELS WITHIN THE RHODO-PHYTAMüller, K. M.1 Sheath, R. G.2, Sherwood, A. R.2,Madabusi, L. V.1, Cannone, J. J.1, Subashchandran,S.1, Lin, N.1 & Gutell, R. R.11Institute of Cellular and Molecular Biology, Univer-sity of Texas at Austin, Austin, TX 78712; 2Dean’sOffice and Department of Botany, University ofGuelph, Guelph, ON N1G 2W1 Canada

Over 400 nuclear SSU rRNA sequences representingall orders of the Rhodophyta were aligned and ana-lyzed using comparative sequence analysis. Numerousnucleotide positions and structural elements werefound that delineated various taxonomic groups. The1245 region (E. coli numbering) contained a loop thatdiffered in size between two conserved helices andclearly separated the Florideophyceae [3 nt (.95% of268 sequences)], Bangiales [13 to 14 nt (100% of 116sequences)] and remaining Bangiophyceae includingthe Cryptophyta nucleomorphs [four to eight nt(100% of 32 sequences)]. In addition, members ofthe Thoreaceae were found to have additional helicesin the 650 and 1139 region of which a correspondingstructure was not present in any other red algal SSUrRNA gene sequence. Base-pair and nucleotide signa-tures differentiated the Bangiales, Florideophyceae,Bangiophyceae (not including Bangiales) and Hilden-brandiales at three levels of comparison: within theRhodophyta (.400 sequences), the Eukaryota (notincluding Rhodophyta; .1300 sequences) and threekingdom (Archaea, Bacteria, 2 organelles, Eukaryota;.7000 sequences). For example, all members of theHildenbrandiales have a change in the base-pair512:539 that is a region of functional importance. Se-quences from the Eukaryota, Archaea, Bacteria andtwo organelles have a C:G or a U:A in this positionwhereas the Hildenbrandiales have a C:A pair. Thisanalysis raises the possibility of utilizing structural fea-tures of nuclear SSU rRNA and sequence signaturesto support and delineate phylogenetic clades withinthe Rhodophyta.

149COMBINED EFFECTS OF MACRONUTRI-ENTS AND METALS ON THE ADRIATICGREEN ALGA ULVA RIGIDA C.AG.Munda, I. M.1 & Veber, M.2

1Centre for Scientific Research of the Slovene Academyof Science & Arts, Gosposka 13, SI-1000 Ljubljana,Slovenia; 2University of Ljubljana, Faculty of Chemis-try & Chemical Technology, Murnikova 8, SI-1000Ljubljana, Slovenia

The ephemeral green alga Ulva rigida C. Ag. is com-mon in polluted and eutrophicated sites of the north-ern Adriatic. Its tolerance and responses to the com-bined effects of excess macronutrients (nitrates,phosphates) and metals (Mn, Co, Zn) that are essen-tial micronutrients were studied in vitro regardinggrowth expressions, survival, elemental composition(N, C, P), and metal accumulation. Plants belongingto vernal/estival and autumnal populations were com-pared. Excess nutrients were applied together withthe single metals. Nitrate and phosphate were usedseparately and in a dual combination. In control sam-ples that lacked metals, it was obvious that plants be-longing to vernal and estival populations grew betterin phosphate than in nitrate enriched media and thatthe opposite was true for autumnal plants. The pres-ence of metals altered the responses of U. rigida to ex-cess nutrients. In some of the samples a relationshipbetween Mn accumulation and growth was indicated,Mn promoting growth. Metal accumulation wasgreater in the autumnal than in the vernal and estivalplants, being the highest for Mn and lowest for Zn. Acomparison between experimental series of differentduration revealed that the metal accumulation in-creases time-dependently for Mn and Co. The N andP content of the plants followed the nutrient enrich-ment of the media. Autumnal plants accumulatedmore N and P than vernal and estival ones. It was obvi-ous that the presence of metals influences the nitro-gen uptake of U. rigida, in the sequence Mn-Co-Zn.The presence of Mn promotes nitrogen uptake andthat of Zn is inhibitory.

150SEASONAL SUCCESSION OF PHYTOPLANK-TON IN LAKE PRINCE, SUFFOLK, VIRGINIA:PRELIMINARY REPORTMuscio, C.M.Department of Biological Sciences, Old Dominion Uni-versity, Norfolk, VA, 23529 USA

Lake Prince is a reservoir lake that provides the re-gion with drinking water, recreational boating, andfishing. The Virginia Department of Game and In-land Fisheries has an interest in the quantity and qual-ity of phytoplankton production in the lake, especiallyregarding the health of fish populations. Anotherconcern in this reservoir is oxygen availability, andaerators have been installed in the main body of thelake. A year-long examination of the phytoplanktoncommunity structure is being conducted. Duplicatesurface water samples are collected monthly from

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three stations, along with physical and chemical base-line data. Community structure and dominance arebeing examined with regard to the physical andchemical parameters, as well as seasonal climatechanges. Cyanobacteria and Cryptophytes are thedominant spring flora. Diatoms and Chrysophytes aresub-dominant populations.

151PRELIMINARY STUDIES OF SEASONALITY,ECOLOGY, AND SPECIES COMPOSITIONOF ULVOID ALGAL BLOOMS IN WASHING-TON STATENelson, T. A.Blakely Island Field Station, Seattle Pacific University,Seattle, WA 98119-1997, USA

Blooms of green macroalgae can devastate importantfinfish and shellfish habitats. Ulvaria obscura, a rela-tively unstudied green alga, is a major contributor tothese blooms in the San Juan Islands, WashingtonState, USA. The biomass and productivity of this andother ulvoid algae were measured seasonally for twoyears. Experiments comparing the growth rates, re-sponses to desiccation, photoacclimation, and grazerpreference of U. obscura and Ulva fenestrata were con-ducted. Ulvaria blooms tended to occur in the sub-tidal while Ulva blooms were often intertidal. Bothgenera bloomed between late June and September.Despite their superficial similarity, Ulvaria and Ulvadisplay markedly different physiological and ecologi-cal responses. Ulva was capable of faster growth, hadhigher rates of photosynthesis, and was more desicca-tion tolerant than Ulvaria. Ulvaria, however, appearsto be more resistant to grazing than Ulva.

152CONFUSING CONVERGENT MORPHOLO-GIES: DIVERSITY AND DIFFICULTIES INNEW ZEALAND ERYTHROPELTIDALES ANDBANGIALESNelson, W. A.1, Broom, J. E.2, & Farr, T. J.11Museum of New Zealand Te Papa Tongarewa, POBox 467, Wellington, New Zealand; 2Department ofBiochemistry, University of Otago, PO Box 56, Dune-din, New Zealand

An examination of New Zealand species of Porphyraand Bangia has led to the discovery of unexpectedlyhigh diversity. In excess of 30 species of Porphyra and 5species of Bangia can be distinguished, based on 18SrDNA sequence data. It is possible to develop a work-able taxonomic framework to distinguish species ofPorphyra found within this geographic region using arange of characters (morphological, anatomical, bio-chemical, physiological, life history characteristics).However, the taxonomic distinctions do not necessar-

ily reflect phylogenetic relationships revealed by se-quence analyses: convergence in character states isobscuring relationships. In the course of our work wehave discovered that four species, originally describedon the basis of traditional morphological and anatom-ical characters as Porphyra or Bangia, are more closelyrelated to members of the order Erythropeltidalesthan to the Bangiales. These results are challengingus to consider new ways of describing and definingthese organisms. We are finding convergence in char-acter states, not only within Porphyra sens. lat. Butspanning both the Bangiales and Erythropeltidales,which confounds both taxonomic distinctions andalso phylogenetic hypotheses based on morphologyand anatomy. This confusion could be countered ef-fectively by the inclusion of molecular sequence databased on vouchered or type material in descriptionsof taxa in the orders Bangiales and Erythropeltidales.This would allow conclusive identification of collectedmaterial by appropriate molecular tests, which arequicker and more direct identification tools than, forexample, using characters drawn from the growth ofthese organisms under controlled culture conditions.

153THE PHYLOGENY OF CAULERPA BASED ONRDNA INTERNAL TRANSCRIBED SPACERSEQUENCESNemeth, S., Mai, T. T., & Zechman, F. W.Department of Biology, California State University,Fresno, CA 93740 USA

Phylogenetic hypotheses for the pantropical marinegreen algal genus, Caulerpa, were inferred based onanalyses of nuclear-encoded rDNA internal tran-scribed spacer (ITS) sequences. Results of these analy-ses were used to assess the correspondence betweenrDNA phylogeny and traditional sectional taxonomy,to identify synapomorphic morphological characters(including assimilator morphology and chloroplastultrastructure), and to examine marine biogeo-graphic hypotheses for the genus. Ribosomal DNAITS sequences were aligned for thirty-three speciesand intraspecific taxa of Caulerpa. Results indicatelimited correspondence between phylogeny and sec-tional taxonomy for the genus, (e.g., the sections Fili-coideae and Sedoideae were not monophyletic). Incontrast, chloroplast morphology could be mapped tothe tree topology with limited homoplasy. Pantropicalisolates of the filicoidean species, Caulerpa sertulario-ides and Caulerpa mexicana each formed monophyleticgroups. Caulerpa reyesii was included as a derivedtaxon within the Caulerpa taxifolia clade, suggestingthat these species were conspecific and affirmed thelack of correspondence between phylogeny andassimilator morphology. Isolates and various intra-specific taxa of Caulerpa racemosa did not form amonophyletic group. Instead, these taxa formed aheterogeneous assemblage with other sedoidean and

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filicoidean taxa. Within the C. sertularioides clade, Car-ibbean and Atlantic isolates formed a basal paraphyl-etic group, whereas eastern and western Pacific iso-lates formed a more derived monophyletic group.Therefore, these results are not consistent with anIndo-West Pacific origin of this species.

154FINE STRUCTURE OF PHACUS SPLENDENSPOCHMAN (EUGLENOPHYTA)Nudelman, M. A.1, Leonardi, P.2, Farmer, M. A.3& Conforti, V.11Lab. Biologia Comparada de Protistas, Dpto Cs. Bio-logicas, FCEyN, Universidad de Buenos Aires,1428,Buenos Aires, Argentina; 2Lab. Plantas Avasculares,Universidad Nacional del Sur, Bahia Blanca, Argen-tina; 3Center for Advanced Ultrastructural Research,University of Georgia, Athens, USA

The general fine structure of P. splendens Pochman(Section Pleurapsis) is described. This Section com-prises a series of species with very distinctive featuresunshared by the majority of the members of the ge-nus. The cells are pear-shaped in frontal view,rounded at the anterior end, narrowed posteriorly ta-pering in a long twisted tail. In lateral view, the ante-rior margins are asymmetric, undulate to serrate. Thepellicle is strongly striated, with ribs helically ar-ranged, oriented to the left, concavely depressed be-tween adajcent ribs. In transverse section, the pellicleoutline shows a single microtubule in the middle ofeach rib, on the base of a central sulcus. The othertwo are located one at each side of the sulcus. Amongother distinguishing characteristics, the most remark-able feature is the presence of a single chloroplast, afact never reported in this genus before since the min-imal observed number is two and most of the Phacusspecies have been described as having numerous,small and discoid chloroplasts. In longitudinal sec-tion, a large, leaf-like parietal chloroplast is observed.It extends along the entire cell, bearing three promi-nent cup-shaped paramylon caps on the external face.In transverse section is C-shaped. The unusual shapeand localization of the chloroplast and paramylon inthis species resemble descriptions of Cryptoglena pigra,suggesting a closer relationship to this organism thanto other members of Phacus.

155PHYLOGENY OF THE BANGIOPHYCIDAE(RHODOPHYTA) AND THE SECONDARYENDOSYMBIOTIC ORIGIN OF ALGAL PLAS-TIDSOliveira M. C.1 & Bhattacharya D.21Dept. de Botânica, Inst. de Biociências, Univ. de SãoPaulo, R. Matão,Travessa 14, n. 321, 05508-900,São Paulo, SP, Brazil; 2Department of Biological Sci-

ences, University of Iowa, 239 Biology Building, IowaCity, Iowa 52242 USA

The Rhodophyta are composed of the subclasses Ban-giophycidae and Florideophycidae. Two evolution-arily interesting features of the Bangiophycidae are:(1) they are the ancestral pool from which the moremorphologically complex taxa in the Florideophy-cidae have arisen and (2) they are the sources of theplastids, through secondary endosymbioses, for theCryptophyta, Haptophyta, and the Heterokonta. Tounderstand Bangiophycidae phylogeny and to gainfurther insights into red algal secondary endosymbio-ses, we sequenced the plastid-encoded small subunitribosomal DNA coding region (ssu rDNA) from ninemembers of this subclass and from two members ofthe Florideophycidae. Phylogenetic analyses were per-formed with other red algal plus chlorophyll a1c algalplastid ssu rDNA coding regions. Our results are con-sistent with a monophyletic origin of the Florideophy-cidae forming a sister group of the Bangiales. TheBangiophycidae is of a paraphyletic origin, and orderssuch as the Porphyridiales polyphyletic and distrib-uted over three independent red algal lineages. Theplastids of the heterokonts are most closely related tomembers of the Cyanidium - Galdieria group of Por-phyridiales and are not directly related to cryptophyteand haptophyte plastids. The phylogenies providestrong evidence for the independent origins of these“complex” algal plastids from different members ofthe Bangiophycidae.

156SEPARATING POPULATION STRUCTUREFROM POPULATION HISTORY IN ASCO-PHYLLUM NODOSUM (FUCALES)Olsen, J. L. & Stam, W. T.Department of Marine Biology, Centre for Ecological &Evolutionary Studies, University of Groningen, 9750AA Haren, The Netherlands

Ascophyllum nodosum is dominant seaweed along manyrocky intertidal shores throughout the North Atlantic.Next to the kelps, fucalean taxa such as Ascophyllumare the largest macrophytes and provide importanthabitat for invertebrates. Understanding the underly-ing genetic structure of natural populations over arange of spatial scales can reveal how the causes ofstructure may change with scales. Separating popula-tion history from population structure may also beelucidated. The analysis is based on six polymorphicmicrosatellite loci and .1000 individuals. Strong ge-netic structure at small spatial scale was found and isconsistent with demographic models based on long-lived individuals, low recruitment and many sib mat-ings. At large spatial scales only weak population dif-ferentiation was found. This is consistent with recent

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recolonization of the North Atlantic following the lastglacial maximum.

157PICOPHYTOPLANKTON SEASONAL CYCLEAT THE SIO PIER, LA JOLLA, CALIFORNIAPalenik, B. P.Scripps Institution of Oceanography, University of Cal-ifornia, San Diego, La Jolla, CA 92093 USA

The abundance of phycoerythrin-containing cyano-bacteria and picoeukaryotes in water samples fromthe Scripps Institution of Oceanography pier havebeen followed at least weekly for more than two yearsusing flow cytometry. These cyanobacteria show a sea-sonal cycle with generally lower cell numbers duringthe winter, a “bloom” as water temperatures increase,and higher cell numbers during the summer. How-ever the population abundance appears to be morevariable and the magnitude of the annual change incell number is less than reported for coastal Massa-chusetts by Waterbury et al. (1986). Isolates have beenobtained from pier samples and genetic characteriza-tion using rpoC1 (RNA polymerase) sequence data isin progress. The PUB:PEB chromophore ratios of iso-lates assayed using fluorescence excitation spectrarange from about 0.4 (low PUB) to 0.7 (mid-PUB) forisolates grown under white light. The physiologicaland genetic characterization of isolates is being usedto examine the similarities and differences of cyano-bacterial populations from different coastal regimes.Similarly a picoeukaryote has been isolated that has aflow cytometric signature similar to the natural popu-lation. It appears to be a small nonmotile prasino-phyte.

158INTERACTION OF CHLOROPLAST ANDVACUOLES IN CHLAMYDOMONASPark, H., Roberson, R. W., Eggink, L. L., &Hoober, J. K.Department of Plant Biology and Center for the Studyof Early Events in Photosynthesis, Arizona State Uni-versity, Tempe, AZ 85287 USA.

Proteins synthesized within the chloroplast of Chlamy-domonas reinhardtii were recovered in granules withinvacuoles (Park et al., J. Phycol. 35,528-538, 1999). Apo-proteins of light-harvesting complexes, synthesized inthe cytosol in excess of the capacity of the chloroplastto synthesize chlorophyll, also were recovered in vacu-olar granules. The ultrastructure of conventionally-and cryo-fixed cells revealed protuberances of thechloroplast envelope outer membrane that containedstroma-like material and also connections betweenthe outer membrane and vacuolar membrane. Trans-fer of proteins via these structures to vacuoles ap-peared to be a pathway for degradation of chloroplast

material. Purified granules contained polyphosphateas the major component, which seemed to protectproteins in the vacuole from breakdown. A predomi-nant 70 kDa protein in purified granules accumulatedin the cell wall of wild-type cells and in granules ofwall-deficient cells, as revealed by immunolocaliza-tion. This protein entered vacuoles via small vesiclesfrom Golgi, which probably also introduced degrada-tive enzymes into this compartment. Vacuoles thus ap-parently serve as lysosome-like structures as well assecretory vesicles. The membranes of the chloroplastenvelope in cryo-fixed green cells were tightly ap-pressed except where the inner membrane invagi-nated or the outer membrane protruded into the cy-tosol. Whereas conventional fixation showed lack ofappression of thylakoid membranes in a chlorophyllb-less mutant, these membranes appeared as largegrana in images of cryofixed cells. The enhanced im-ages obtained with cryofixation allowed substantial re-finement of our knowledge of the ultrastructure ofthese algal cells.

159IDENTIFICATION OF A GLYCINE DECAR-BOXYLASE GENE IN THALASSIOSIRA WEISS-FLOGII: A PROBE FOR PHOTORESPIRA-TION IN DIATOMSParker, M. S. & Armbrust, E. V.Marine Molecular Biotechnology Laboratory, School ofOceanography, Box 357940, University of Washing-ton, Seattle, WA 98195

Diatoms are responsible for a large percentage of CO2fixation in the world’s oceans. The export of diatom-fixed carbon from the euphotic zone represents a ma-jor sink of CO2 in the global C cycle. Under condi-tions of high light and high O2/CO2, carbon fixationmay be reduced due to photorespiration. The fixationof O2 in photorespiration produces low molecularweight metabolites that cannot be used in the Calvincycle and are either excreted from the cell or ineffi-ciently salvaged in the photorespiratory pathway. Oneof the key enzymes of photorespiration is glycine de-carboxylase (GDC). We have cloned and sequenced acDNA corresponding to the gene encoding the T-pro-tein of GDC from the centric diatom Thalassiosiraweissflogii. This cDNA is 1100 bp and its predictedamino acid sequence shows a 45% identity and a 62%homology with the T-protein from higher plants. Thefirst 20 amino acids display characteristics of mito-chondrial transit peptides, consistent with the local-ization of GDC in the mitochondria of higher plants.Using competitive RT-PCR we have demonstratedthat transcription of this gene is light-dependent.Cells maintained at constant growth-saturating lightconditions have much higher levels of T-protein mes-sage than cells kept in the dark for 25 hours. We arecurrently investigating the effect of other environ-

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mental parameters, such as O2 concentration, on T-protein gene transcription. Ultimately, the goal is touse this gene as a probe for diatom photorespirationin the field. To this end, we are developing degener-ate primers and sequencing this gene from other dia-tom species.

160TAXONOMIC REASSESSMENT OF THEGENUS PADINA (DICTYOTALES, PHAEO-PHYTA) IN THE GULF OF CALIFORNIA,MÉXICOPaul-Chávez, L., Riosmena-Rodriguez, R., &Angeles-Pérez, A.Herbario Ficológico, Mar. Biol. Dept., UABCS, Ap.Postal 19-B, La Paz B.C.S. 23080 México

Padina is one of the most important genera in thecoastal zone of the Gulf of California because of theirbiomass. Eight species have been recorded for thearea: P. tetrastromatica, P. durvillaei, P. gymnospora, P.mexicana, P. caulencens, P. concrescens, P. crispata y P. vi-keersiae based on taxonomic and floristic studies. Un-fortunately, until today, a comparative study of allthese species in a modern context was not available.Intensive surveys in 100 localities around the areayield more than 1000 specimes and 500 slides wereanalyzed and compared with relevant types. Taxo-nomic evaluations were developed using 16 characterscommonly used in the literature. As a result of ouranalysis, only five characters can discriminate species.Based on character analysis and comparisons withproper type material, only three species can be recog-nized in the zone: P. concrencens, P. durvillaei and P.mexicana. In the case of P. crispata, we conclude that itis a heterotypic synonym for P. mexicna. But in thecase of P. gymnospora, P. tetrastromatica and P. vikersiae,all previous records represent mis-identifications.

161SEASONAL AND ZONAL VARIATION INNITROGEN SOURCE FOR FOUR INTER-TIDAL SEAWEEDS FROM NEW ZEALANDPhillips, J. C. & Hurd, C. L.Department of Botany, University of Otago, P. O. Box56, Dunedin, New Zealand

Seasonal patterns in nitrogen uptake by four speciesof intertidal macroalgae (Stictosiphonia arbuscula, Apo-phlaea lyallii, Scytothamnus australis, Xiphophora gladi-ata) from Otago in New Zealand’s south island wereinvestigated. Field-collected material from species oc-curring at different shore heights was exposed to inor-ganic (NO23, NH14) and organic (urea) nitrogen atdifferent concentrations (5mM, 30mM), and the rateof uptake over 30min intervals for 3hr was deter-mined. Active uptake of nitrate was shown by all spe-

cies in both seasons but uptake rates were 2–5 timesgreater in summer compared to winter. Ammoniumuptake was highest in all species regardless of season,indicating a preference for this form of nitrogen. Forall species, urea uptake was negligible during winterbut represented a substantial proportion of the totalnitrogen taken up during summer. Comparison ofspecies in relation to their shore position revealed dif-ferences in uptake rates for each nitrogen source.These results suggest that intertidal seaweeds growingat different shore positions employ different strategiesfor procuring nitrogen in an environment where nu-trient supply may be limited.

162SONDERELLA, LEMBERGIA AND THE NEWTRIBE SONDERELLEAE (RHODOMELACEAE,RHODOPHYTA)Phillips, L. E.1, Nelson, W. A.2 & Kraft, G. T.11School of Botany, University of Melbourne, Victoria3052, Australia; 2Museum of New Zealand Te PapaTongarewa, PO Box 467, Wellington, New Zealand

The monospecific genus Sonderella is endemic to Aus-tralia and has been the subject of speculation with re-gard to its taxonomic position. When the anatomyand reproduction of this genus were comprehensivelydescribed by Womersley in 1965, he recommended itsinclusion in the Rhodomelaceae and foreshadowedthat it would warrant its own tribe. Recent molecularinvestigation has confirmed its position within theRhodomelaceae. Classical anatomical investigation ofthe rare and poorly-known New Zealand endemic ge-nus Lembergia has shown that it shares many featureswith Sonderella, including vegetative construction andposition and construction of the reproductive struc-tures. Molecular investigations of the 18S rRNA genesupport the close relationship of the two genera andtheir inclusion within the Rhodomelaceae as a sepa-rate tribe, the Sonderelleae tribus novum.

163TAXONOMY OF THE LENORMANDIA - LENOR-MANDIOPSIS COMPLEX (RHODOMELACEAE,RHODOPHYTA)Phillips, L. E.1, Nelson, W. A.2 & Kraft, G. T.11School of Botany, University of Melbourne, Victoria3052, Australia; 2Museum of New Zealand Te PapaTongarewa, P. O Box 467, Wellington, New Zealand

The genus Lenormandia is composed of nine speciesfrom Australia and New Zealand. Some of the theseare well known, but others are rare, obscure and ill-defined. We have examined material of all describedspecies and found that they fall into two discretegroups that differ in apex morphology and position ofreproductive structures. Plants of the first group, con-

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taining the type species L. spectabilis, have a cleft apexand reproductive structures produced directly on theblade surface, whereas those of the second grouphave a strongly inrolled apex and produce reproduc-tive structures dorsally on small branchlets which ariseeither from the margins or the midrib. The groupswere also found to form discrete clades on analysis of18S rRNA sequences. All the members of the firstgroup are endemic to Australia, whereas the secondgroup, designated by the new genus name Adamsiella,contains two previously described New Zealand spe-cies and a single Australian representative. In addi-tion, two new species are described in this group fromNew Zealand. Members of the closely related genusLenormandiopsis were also examined and the type spe-cies, L. latifolia, was found to conform in apex mor-phology and position of reproductive structures to thegenus Lenormandia. Accordingly Lenormandiopsis hasbeen subsumed within Lenormandia. The remainingthree members of the former genus Lenormandiopsis,however, were found to differ from both the type spe-cies and the genus Lenormandia and consequentlyhave been transferred to the separate genus Geraldia,along with a new species from Geraldton, WesternAustralia which is designated as the type.

164GLOBAL SYSTEMATIC AND PHYLOGE-NETIC ANALYSIS OF SARGASSUM IN THEGULF OF MEXICO, CARIBBEAN ANDPACIFIC BASINPhillips, N.1, Smith, C.2, Morden, C.2, &Fredericq, S.11Department of Biology, University of Louisiana atLafayette, Lafayette, La. 70504 USA; 2Botany Depart-ment, University of Hawaii, 3190 Maile Way, Hono-lulu, HI 96822. USA

Sargassum is one of the most species-rich genera in thebrown algae with over 400 described species world-wide. The bulk of these species occurs in Pacific-In-dian ocean waters with only a small portion found onthe Atlantic side of the Isthmus of Panama. Sargassumalso has one of the most subdivided and complex tax-onomic systems used within the algae. Systematic dis-tinctions within the genus are further complicated byhigh rates of phenotypic variability in several key mor-phological characters. Molecular analyses in such sys-tems should allow testing of systematic concepts whileproviding insights into speciation and evolutionarypatterns. Global molecular phylogenetic analyses us-ing both conserved and variable regions of theRubisco operon (rbcL and rbcL-IGS-rbcS) were per-formed with species from the Gulf of Mexico, Carib-bean, and Pacific basin. Results confirm earlier analy-ses based on rbcL-IGS-rbcS from Pacific species at thesubgeneric and sectional level while providing addi-tional insights into the systematics and phylogenetics

on a global scale. For example, species east of the Isth-mus of Panama form a distinct well-resolved cladewithin the tropical subgenus. This result in sharp con-trast to traditional systematic treatments but providesa window into the evolutionary history of this genus inthe Pacific and Atlantic Ocean basins and a possiblemeans to time speciation events.

165MODULATION OF VERY-LONG CHAIN (C28)HIGHLY UNSATURATED FATTY ACIDS INPROROCENTRUM MININUM (DINOPHYCEAE)BY SELENIUMPlace, A., Adolf, J. E. & Lund, E.Center of Marine Biotechnology, Columbus Center,East Pratt Street Center, Baltimore, MD 21202 USA

Recently, very-long-chain (C28) highly unsaturatedfatty acids (VLC-HUFA) were identified in seven ma-rine dinoflagellate species (Manour et al., Phytochem-istry, 1999, 50: 541–548). In general, the proportionof these fatty acids accounted for less than 2.3% of thetotal fatty acids in these species. As part of a study in-vestigating the modulation of the hemolytic fatty acid18:5n3, cultures of Prorocentrum mininum were grownin artificial seawater with varying molarities of sodiumselenite (0, 1, 10, and 100 nM). Optimal growth wasobserved at 1 nM with this media. As expected, thelevel of 18:5n3 was modulated by the selenium in theculture medium (7.0 6 0.2, 14.5 6 0.6, 7.4 6 0.8, and3.9 6 0.8% of total fatty acid, respectively), with thehighest percentage found at 1 nM. Unexpectedly thelevel of VLC-HUFA (28:8n3) increased to 7.3 6 2.8%at 0 nM sodium selenite, while at all other seleniteconcentrations the VLC-HUFA was less than 1%. Apossible biochemical basis for this finding will be dis-cussed.

166CALCIUM OXALATE CRYSTALS IN THEGREEN ALGA SPIROGYRA SP. (ZYGNE-MATALES, CHLOROPHYTA)Pueschel, C. M.Department of Biological Sciences, State University ofNew York at Binghamton, Binghamton, NY 13902USA

Specimens of an unidentified species of the freshwa-ter green alga Spirogyra were found to have abundantcruciate cellular inclusions up to 34 micrometerslong. A crystalline nature was shown by birefringencein polarized light. Despite their large size and com-plex shape, these inclusions did not occur free in thelarge central vacuole. Instead, they were associatedwith cytoplasmic strands that spanned the space be-tween gyres of the parietal spiral chloroplasts and withstrands that suspended the nucleus in a cytoplasmic

56 PSA ABSTRACTS

embayment of the central vacuole. Some crystalsmoved directionally along the cytoplasmic strands,and their movement was arrested by cytochalasin B,suggesting that actin microfilaments had a role incrystal movement. Solubility tests showed that the in-clusions were composed of calcium oxalate; they dis-solved rapidly in weak hydrochloric acid without effer-vescence, but they were not soluble in concentratedacetic acid or sodium hypochlorite. A colorimetric en-zymatic test for oxalate was used to demonstrate mi-croscopically the presence of oxalate and to quantifythe amounts. The calcium oxalate crystals were sur-rounded by a water-soluble organic matrix that re-tained the shape of the crystal even after demineral-ization. Scanning electron microscopy was used toexamine the morphology of isolated crystals.

167EXCHANGES OF INFORMATION, ENERGY &MATERIALS IN SYMBIOSESRaven, J. A.Department of Biological Sciences, University ofDundee, Dundee DD1 4HN, United Kingdom

Symbiosis is important in the cell and environmentalbiology of algae. Some examples involving the authorand numerous collaborators include: 1) chloroplastsof eukaryotic algae arose from endosymbioses. Plas-tids are incapable of independent existence; most ofthe genes of the cyanobacterial photobiont have beenlost, and the majority of the rest have been trans-ferred to the nuclear genome. Some of the genes re-tained by the plastid are those whose transcription iscontrolled by environmental cues transduced by theorganelle. The general trend is for organelle genes tobe transferred to the nucleus, escaping plastid redoxactivities generating mutagenic free radicals; 2) symbi-oses involving potentially free-living photobionts in-clude marine lichens and sponges with cyanobacterialsymbionts. For the lichen, Lichina, inorganic carbonacquisition appears to involve inorganic carbon trans-port by the mycobiont, and for the sponge, Cymbas-tella, the flagellar activity of the sponge is probablyimportant for inorganic carbon supply to the photo-biont; 3) the Australasian fucalean, Notheia, is an obli-gate epiphyte on the fucaleans, Hormosira and Xipho-phora; the four species involved all contain thehexitol, altritol. Notheia anomala is known to be phylet-ically-distant from the other five altritol-containingspecies. Can Notheia synthesize altritol, or is it ob-tained from the phorophyte?; 4) Sacoglossan gastro-pods retain kleptoplastids (not strictly symbionts)from ulvophycean (or rhodophycean) marine algae.Analyses of the natural abundance of stable carbonisotopes suggest significant contribution of klepto-plastid photosynthesis to the carbon and energy bud-get of the mollusks.

168PATTERNS AND CONSEQUENCES OF SPOREDISPERSAL IN THE GIANT KELP, MACROCYS-TIS PYRIFERAReed, D. C.1, Raimondi, P. T.2, & Washburn, L.31Marine Science Institute, University of California,Santa Barbara, CA, 93106, USA; 2Department of Biol-ogy, University of California, Santa Cruz, CA, 95064,USA; 3Department of Geography, University of Califor-nia, Santa Barbara, CA 93106, USA

We investigated patterns of spore dispersal in the gi-ant kelp Macrocystis pyrifera by collecting 80 indepen-dent measurements of spore dispersal from isolatedindividuals and isolated groups of individuals over atwo-year period. Our results indicate that giant kelpspores routinely disperse both short (i.e. a couplemeters) and long (i.e. hundreds to thousands ofmeters) distances depending on the oceanographicconditions. One consequence of spore dispersal overshort distances is self-fertilization (i.e., fertilization be-tween male and female gametophytes derived fromthe same sporophyte). Field experiments designed totest the effects of self-fertilization on lifetime fitness inMacrocystis revealed significant inbreeding depression.Birth rates in self-fertilized populations were ca. 50%of those produced from outcrossing, which lead tosignificant differences in cohort size that persisted upthrough the adult stage. In contrast to outcrossedpopulations, very few individuals produced from self-ing became reproductively mature, and those that didwere significantly less fecund than outcrossed individ-uals. By contrast, long-range dispersal of spores leadsto increased rates of outcrossing. However, long-rangedispersal is typically accompanied by massive dilutionof spores, leading to low densities of spore settlement.Sparse spore settlement decreases the overall chanceof fertilization in the microscopic gametophyte gener-ation thereby reducing the potential for colonizationof the macroscopic sporophyte stage. Large popula-tion size of adult sporophytes coupled with the syn-chronous release of spores in response to environ-mental cues can help offset the effects of sporedilution and extend the distances over which giantkelp is able to colonize.

169THE COMPOSITION AND TOXICITY OFDINOFLAGELLATE BLOOMS IN THE SAL-TON SEA, CALIFORNIAReifel, K. M.1, Tiffany1, M. A.1, McCoy, M. P.2 &Hurlbert, S. H.11Department of Biology and Center for Inland Waters,San Diego State University, 5500 Campanile Drive,San Diego, CA 92182 USA; 2Scripps Institution ofOceanography, University of California at San Diego,La Jolla, CA 92093-0212 USA

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Phytoplankton blooms have been implicated in mor-tality events of diverse groups of organisms includingfish, birds and humans. About 300 species have beenreported to form “red tides,” or surface discolorationsdue to high densities, but only 60–80 of these speciesproduce harmful blooms. In marine systems, di-noflagellates account for 75% of all harmful algalbloom species. The Salton Sea is a large saline lake lo-cated in southeastern California, USA. The lake iseutrophic largely because it is in a closed basin and re-ceives most of its input from agricultural and munici-pal wastewaters. Dinoflagellates comprise a significantportion of the phytoplankton biomass, particularly inwinter, often resulting in “red” or “brown” tides. Todate, 16 species of dinoflagellates have been identi-fied from the Salton Sea, and many other unidenti-fied forms have also been documented. In 1992,150,000 eared grebes were found dead over a periodof several months at the Salton Sea. This mortalityevent was among the largest of any bird species. Theprincipal cause remains unknown, but algal toxinswere suspected. A survey of the composition and tox-icity of algal blooms was undertaken in 1999, and wereport results from blooms where dinoflagellatesdominated. Dominant species included Gonyaulaxgrindleyi, Gymnodinium spp., Gyrodinium uncatenum,Heterocapsa niei, and an unidentified scrippsielloid. Al-though most samples showed activity in a brineshrimp lethality assay, all were negative in a mousebioassay. This evidence suggests that toxins from di-noflagellate blooms in the Salton Sea are not respon-sible for eared grebe mortality events.

170SPECIES-SPECIFIC RESPONSE IN ALKALINEPHOSPHATASE ACTIVITY OF FRESHWATERPHYTOPLANKTON IN A NUTRIENT ENRICH-MENT EXPERIMENTRengefors, K.1, Haupert, C.2, Ruttenberg, K. C.2,Taylor, C.1, Howes, B. L.3, & Anderson, D. M.11Biology Department, Woods Hole Oceanographic Insti-tution, Woods Hole, MA 02543 USA; Department ofChemistry and Geochemistry, Woods Hole Oceano-graphic Institution, Woods Hole, MA 02543 USA;3University of Massachusetts Dartmouth, Dartmouth,285 Old Westport Rd., North Dartmouth, MA 02747USA

A new method was utilized to study species-specific re-sponses of phytoplankton to phosphorus limitation ina nutrient enrichment experiment. A substrate, ELF,produces a fluorescent precipitate at the sites of alka-line phosphatase (AP), which makes it possible to vi-sually detect phosphorus (P) limitation in individualcells of multiple species. Lake water was incubated inthe laboratory to induce nitrogen (N) or P limitation.Initially, little or no ELF labeling was observed for anyof the phytoplankton species, indicating a general

lack of P limitation. This observation was supportedby low bulk AP activity in the initial field samples. Dur-ing the experiment, several chlorophyte taxa (Coelas-trum, Eudorina, a solitary spiny coccoid) were driven toP limitation, as evidenced by a high percentage ofcells displaying ELF labeling when inorganic N wasadded. Taxa such as Actinastrum and Dictyosphaerium,on the contrary, were never P limited. Little or noELF was observed in cyanobacterial species, suggest-ing that P limitation was not achieved in these organ-isms. Using traditional bulk AP activity, significantlyhigher levels of AP activity were observed in treat-ments with inorganic N additions, compared to thosewith phosphate additions. ELF labeling generally fol-lowed the trend of bulk AP, except in species that didnot dominate the biomass. Finally, we noted that allspecies observed were ELF labeled at least on one oc-casion, except for fragile flagellates which did notwithstand the labeling procedure.

171RANGE EXTENSION OF CUTLERIA HAN-COCKII (CUTLERIALES; PHAEOPHYTA) TOTHE SOUTHWESTERN GULF OF CALIFOR-NIA, MÉXICORiosmena-Rodríguez, R., Paul-Chávez, L. & Hino-josa-Arango, G.Hebario Ficológico, Depto. Biol. Mar., U.A.B.C.S., Ap.postal 19-B, La Paz B.C.S. 23080, México

A range extension of Cutleria hancockii Dawson to thesouthern portion of the Gulf of California is pre-sented based on collections in Concepción Bay, LaPaz Bay and Muertos Bay between March, 1996 andMay, 2000. Mature gametangial and sporangial plantswere collected in several localities in the low intertid-ial zone and in subtidial areas. The present recordsrepresent a range extension of 500 km for the specieswith the new southern limit in Punta Perico in LosMuertos Bay. The plants mostly were observed in lowintertidial-shallow subtidial areas associated with Sar-gassum forest, but also were observed at depths of 30ft. Based on analysis of the basic morphological andanatomial features of the plants, significant differ-ences within geographic position and depth distribu-tion were noted. Our data suggest that the tempera-ture may be the determining factor in thedistribution of this species.

172DEMOGRAPHY OF FRONDS OF SARGASSUMLAPAZEANUM FROM SOUTHERN BAJA CALI-FORNIA, MEXICO, DURING EARLY STAGESRivera, M. G.1 & Scrosati, R.21Centro Interdisciplinario de Ciencias Marinas, AP592, La Paz, 23000 BCS, Mexico; 2Centro de Investi-gaciones Biologicas del Noroeste, AP 128, La Paz,23000 BCS, Mexico

58 PSA ABSTRACTS

In terms of biomass, Sargassum lapazeanum (Phaeo-phyceae, Fucales) is one of the most important sea-weeds in La Paz Bay, on the southeastern coast of theBaja California Peninsula, Mexico. This species can befound year-round in shallow subtidal sites. Standingbiomass is lowest between fall and winter and highestbetween spring and summer. We are currently study-ing the annual demography of fronds as a necessarystep to understanding the mechanisms of populationregulation. Work is being done on a bed of about 90m in length and three m in width. At this stage of ab-stract submission, we can report results for winter only.Random samples were collected in February and inMarch 2000 to estimate stand biomass, frond density,and size (frond length) structure. In addition, we la-beled fronds with numbered plastic tags to estimate theirrates of growth and of mortality during this period.Rates of recruitment were estimated from a combinedanalysis of the above. In February, fronds were allshorter than 6.5 cm. Between February and March, meantotal frond density increased from 122 to 776 frondsm22 (n 5 30 quadrats). The mean recruitment ratewas 667 fronds m22, the mean growth rate was 0.5 cmday21 (n 5 60 fronds), and the mean mortality ratewas 43 fronds m22. From last year’s preliminary obser-vations, we expect to observe peaks of biomass and ofreproduction in late spring, followed by negativegrowth rates and high mortality rates during summer.

173EVOLUTION OF BIOLUMINESCENCE INMARINE DINOFLAGELLATESRobertson, D. L. & Hastings, J. W.Department of Molecular and Cellular Biology, Har-vard University, Cambridge, MA 02139 USA

Bioluminescence is broadly distributed in marine di-noflagellates and has been intensively studied in Lin-gulodinium (Gonyaulax) polyedra. In this species, biolu-minescence is regulated in a circadian fashion; theenzyme (luciferase) and the luciferin (substrate)-binding protein are synthesized and degraded on adaily basis. Synthesis of both proteins is regulated atthe level of translation. The L. polyedra luciferase geneis composed of three contiguous domains that aregreater than 75% identical at the nucleic acid level.Possible explanations for the high degree of se-quence conservation include: (1) the domains evolvedthrough a recent duplication event; (2) the sequencesimilarity is maintained by a molecular process such asgene conversion; or (3) there is a functional role asso-ciated with the primary nucleic acid sequence, such asin the translational regulation of luciferase expres-sion. The phylogenetic relationship of dinoflagellatespredicted from 18S rDNA genes provides a frame-work for examining the molecular evolution of theregulation of luciferase expression and of genes en-coding luciferase and the luciferin-binding protein.In particular, we are examining the evolution of the

circadian rhythm of bioluminescence and of lu-ciferase abundance, the presence/absence of the lu-ciferin-binding protein, and the molecular structureof the luciferase gene. We anticipate that this ap-proach will distinguish between regions of the lu-ciferase molecule that are conserved for enzyme func-tion versus those concerned with the regulation ofprotein expression. In addition, it will provide insightinto the evolution of the regulatory processes andpathways.

174ANALYSIS OF NUCLEAR MUTANTS OFCHLAMYDOMONAS DEFICIENT IN THE ACCU-MULATION OF SPECIFIC CHLOROPLASTRNASRochaix, J. D.1, Boudreau, E.1, Nickelsen, J.2,Lemaire, S.1, Vaistij, F.1 & Goldschmidt-Clermont,M.11Departments of Molecular Biology and Plant Biology,University of Geneva, Geneva, Switzerland; 2RuhrUniversität, Bochum, Germany

Genetic analysis has revealed that the accumulation ofseveral chloroplast mRNAs of the green alga Chlamy-domonas reinhardtii requires specific nucleus-encodedfunctions. We have characteized three nuclear mu-tants, nac2, 222E and F24 which lack psbD, psbB andpsaB mRNA, respectively. In each case we have shownthat the target of the nucleus-encoded function af-fected in these mutants is the 59 untranslated regionof the corresponding mRNA (3, 4, 5). We have clonedthe nuclear Nac2 and Mbb1 genes by rescue of themutants which are deficient in the accumulation ofthe mRNAs of psbD and the psbB/psbT/psbH chloro-plast transcription unit.. Nac2 encodes a hydrophilicpolypeptide of 1385 amino acids with 9 tetratricopep-tide repeats (TPR) in its C-terminal half whereasMbb1 encodes a polypeptide of 662 amino acidswhich also contains 9 TPRs. Both proteins contain aputative chloroplast transit peptide at their N-termi-nal end. They have been tagged with the HA epitopeand localized in the stromal compartment of the chlo-roplast. Nac2 and Mbb1 are part of a high molecularweight complex of 500 and 250 kDa, respectively,which is associated with RNA in the case of Nac2. Achange of a conserved Ala residue of the fourth TPRmotif by site-directed mutagenesis completely abro-gates Nac2 function indicating that this TPR is impor-tant for psbD mRNA stability, processing and/ortranslation.

175PRELIMINARY FLUORESCENCE AND ULTRA-STRUCTURAL OBSERVATIONS IN DICTY-OSPHAERIUM PULCHELLUM (CHLOROCOC-CALES, CHLOROPHYCEAE)Rodríguez, M. C.1, de la Peña, G. & Leonardi, P. I.2

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1Departamento de Ciencias Biológicas, Facultad deCiencias Exactas y Naturales, Universidad de BuenosAires, 1428 Buenos Aires, Argentina; 2Departamentode Biología, Bioquímica y Farmacia, Universidad Na-cional del Sur, 8000 Bahía Blanca, Argentina

Dictyosphaerium pulchellum is a common freshwaterphytoplankter. After cell division, autospores remainattached to each other in a characteristic fashionthrough the remnants of the partially hydrolyzedmother cell walls (tracts), originating up to 64-celledcolonies immersed in abundant mucilage. Stainingwith ruthenium red and toluidine blue revealed muci-lage acid properties, probably due to uronic acids inpolysaccharides. Tracts and cell walls were PeriodicAcid-Schiff positive and showed fluorescence with cal-cofluor white, indicating the presence of fibrillarpolysaccharides of the type cellulose and beta-man-nans. Intense fluorescence with berberine suggestedsome hydrophobic coating of fibrillar polysaccha-rides. Though cell walls proved to be acetolysis resis-tant, no secondary fluorescence was observed withprimuline, suggesting that the hydrophobic polymerin the cell wall differed from algaenan. Ultrastructuralobservations revealed no trilaminar structure in thecell wall, but ruthenium red stained sections exhib-ited a “zipper-like” band in the outermost cell walllayer both in autospores and mother walls. The cellshave a large cup-shaped chloroplast containing a sin-gle pyrenoid with the matrix traversed by double thy-lakoids and circled by starch plates. A lobulated nu-cleus occupied the concavity of the chloroplast.Dictyosomes appeared closely related with the nuclearenvelope. Several vacuoles scattered in the cytoplasmand close to the nucleus showed electron dense con-tent, which could also be observed in the periplas-malemmal space. Fluorescent dye quinacrine alsoshowed active vesicle traffic.

176PROTEIN EXPRESSION DURING HEATSTRESS IN THERMO-INTOLERANT ANDTHERMO-TOLERANT DIATOMSRousch, J. M., Bingham, S. E., & Sommerfeld, M.R.Department of Plant Biology, Arizona State University,Box 871601,Tempe, AZ 85287 USA

To better understand how diatoms are capable of re-sponding to environmental stress, protein expressionduring heat treatment of a thermo-intolerant (Phaeo-dactylum tricornutum) and thermo-tolerant (Chaetocerosmuelleri) diatom (Chrysophyta) was investigated. Thestress response is a universal and conserved mecha-nism of cell survival to unfavorable conditions. Typi-cally, a 10 to 158 C temperature elevation above cellgrowth optimal causes constitutively expressed pro-

teins to decrease and heat shock proteins (HSPs) toincrease. HSPs are categorized by molecular weightamong five classes with each apparently specializedfor a particular function that enhances cell survival.One-dimensional SDS-PAGE of diatoms subjected toheat treatment revealed that P. tricornutum exhibited atypical stress response, but C. muelleri did not exhibit acharacteristic response even at a greatly elevated tem-perature (508 C). This result was confirmed by totalsoluble protein assays. Chaetoceros muelleri may containhigher basal levels of HSPs than P. tricornutum allow-ing C. muelleri to better tolerate elevated tempera-tures. Western blot analysis using pea HSP70 (70 kDa)antisera of heat-treated P. tricornutum and C. muellerivalidated the hypothesis that thermo-tolerant cellscontain higher levels of constitutively expressed HSPs.Two-dimensional gel electrophoresis of heat-treatedcells indicate that the small HSPs (17–30 kDa) playeda role in the stress response similar to that found invascular plants. Ongoing work is focused on the ma-nipulation of the stress response through over-expres-sion of key hsp genes.

177REVISED CLASSIFICATION OF THE GENUSPACHYMENIA BASED ON MORPHOLOGICALAND MOLECULAR CHARACTERSRussell, L. K.1, Hurd, C. L.1, Nelson, W.A.2,Falshaw, R.3, & Broom, J. E.41Botany Department, Otago University, P.O. Box 56,Dunedin, New Zealand; 2Museum of New Zealand TePapa Tongarewa, P.O. Box 467, Wellington, NewZealand; 3Industrial Research Limited, P.O. Box 31-310, Lower Hutt, NZ; 4Biochemistry Department,Otago University, P.O. Box 56, Dunedin, NewZealand

Taxonomic discrimination in the genus Pachymenia(Rhodophyta) in New Zealand is based primarily onphenotypic characters of the thallus. The taxonomicproblems raised by this classification method are dueto highly variable thallus characters such as bladethickness, blade width, degree of thallus branching,and variation in anatomical characters. Delineation ofspecies is further complicated by a lack of adequateknowledge about the responses of phenotype to envi-ronmental variation. There are currently three spe-cies recognized in this genus that are endemic to NewZealand: a prostrate species P. crassa, and two erectspecies, P. laciniata and P. lusoria. In this study, two ap-proaches are used to investigate the current delinea-tion of these species. Morphological and anatomicalcharacters of field collected material and herbariumspecimens from throughout the species’ distribu-tional ranges were quantified. Multivariate analyseswere used to identify discrete phenotypic groups. Spe-cies relationships were further analyzed by quantify-

60 PSA ABSTRACTS

ing the variation found within the internal tran-scribed spacer region (ITS) of the nuclear ribosomalDNA. The results obtained from both approaches willbe discussed with regards to possible re-classificationof species relationships within this genus. We suggestthat the two erect species should be merged, and thecurrently recognized P. lusoria should be separatedinto at least two taxonomic groups.

178COALESCENCE VERSUS COMPETITION:FIELD AND LABORATORY STUDIES OF INTRA-AND INTERSPECIFIC ENCOUNTERS AMONGCOALESCING SEAWEEDSSantelices, B., Correa, J. A., Aedo, D.,Hormazábal, M. & Flores, V.Departamento de Ecología, Facultad de Ciencias Bi-ológicas, P. Universidad Católica de Chile, Casilla114-D, Santiago, Chile

Classical ecological theory predicts that whenevergrowing individuals share a common and limiting re-source, such as substratum in mid-intertidal and shal-low subtidal habitats, preemptive competition will oc-cur determining species abundance and distributionpatterns. However, conspecificity of several ecologi-cally dominant Rhodophyta may coalesce when grownin laboratory cultures. The extent at which intraspe-cific coalescence occurs in the field and whether theprocess may also happens during interspecific en-counters remain to be determined. If intra- and inter-specific coalescence effectively occurs, then coexist-ence through coalescence rises as an alternative tocompetition among red-algal dominated intertidaland shallow subtidal communities. Populations ofMazzaella laminarioides and Nothogenia fastigiata livingin mid-intertidal, semi-exposed rocky habitats in Cen-tral Chile are being used to test the above ideas. Intra-and interspecific encounters occur in the fieldthroughout the year. Coalescence does occur amongconspecific partners but it has not been detected ininterspecific encounters. Rather, a thick interface ofcompressed cells, necrotic tissues and cyanobacterialnodules is formed between the two contacting part-ners. In addition, observations of laboratory culturesindicate that spore germination, germling survivaland differentiation of erect axes in bispecific culturesmay be reduced when compared to single-species con-trols. Interspecific differences in growth and differen-tiation rates appear as the mechanisms explaining alack of coalescence and negative effects during inter-specific contacts. On the other hand, the existence ofconspecific coalescence in the field suggests this pro-cess should be considered as a real alternative to in-traspecific competition among coalescing Rhodo-phyta.

179PREDAEA LUCESCENS SP. NOV., A NEWCOOL-TEMPERATE AUSTRALIAN SPECIESWITH UNIQUE, UNDIFFERENTIATED NUTRI-TIVE FILAMENTSSaunders, G. W.1 & Kraft, G. T.21Department of Biology, University of New Brunswick,Fredericton, NB, Canada; 2School of Botany, Univer-sity of Melbourne, Parkville, Victoria 3052, Australia

The red algal genus Predaea (Schizymeniaceae, Gigar-tinales) includes approximately a dozen species oftropical and subtropical distribution. Plants are gelati-nous in consistency, and the carpogonial branchesand auxiliary cells are widely separated in female ga-metophytes (non-procarpy). Predaea is distinguishedfrom other red algal genera in possessing clusters ofsmall rounded nutritive cells that are borne on theone proximal and distal two cells directly attached tothe auxiliary cell. We describe a new species from cool-temperate (10–188 C yearly range) southeastern Aus-tralia that, unlike the tropical and subtropical species,lacks the typical gelatinous texture and has dwarf veg-etative filaments of normally contoured cells associ-ated with the auxiliary cell rather than small clustersof spherical nutritive cells. Anatomical and moleculardata are combined to postulate the phylogenetic af-finities of the new species to others of the genus, tohighlight relationships of Predaea to other genera ofthe Schizymeniaceae, and to consider this family rela-tive to others now placed in the Gigartinales.

180A CANDID ASSESSMENT OF SYSTEMATICSIN THE LAMINARIALES: MUDDLED MOR-PHOLOGIES AND SKETCHY SEQUENCESSaunders, G. W., Lane, C. E. & Mayes, C.Department of Biology, University of New Brunswick,Fredericton, NB, Canada

Algae of the Alariaceae, Laminariaceae and Lessoni-aceae are the largest, most complex, and, arguably,most fascinating of the seaweeds. It is, therefore, aprofound paradox that these species remain in taxo-nomic chaos despite the contemporary emphases onsystematics. Setchell and Gardner established the clas-sification system in 1925, recognizing these familieson the basis of clear morphological features. At thattime, however, they acknowledged that some specieshad features consistent with placement in two fami-lies, or that obscured logical placement in any of thefamilies. Ironically, the problems noted by Setchelland Gardner have been ignored and the system hasbecome entrenched in kelp literature. Initial molecu-lar studies highlighted the shortcomings noted by Set-chell and Gardner, and further indicated that little ofthe morphology-based system was natural. It was obvi-

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ous that the diagnostic morphological features, pres-ence or absence of sporophylls and ontogenetic split-ting, were ‘noisy’ being gained and lost independentlymany times in kelp evolution. Despite the insights ofthe initial molecular studies, they had limitations andkey relationships remained unresolved. The investiga-tions used the Internal Transcribed Spacers (ITS) ofthe ribosomal cistron that have phylogenetic limita-tions owing to their short length, which is exacer-bated by the many variable regions that can’t bealigned confidently and must be removed prior tophylogenetic analyses. Many molecular publicationshave appeared subsequent to the first ITS results, andtheir contribution towards elucidating kelp phylogenywill be assessed. Current investigations using theLarge Subunit ribosomal DNA (LSU) for kelp system-atics will also be discussed.

181INTRODUCED MACROALGAE IN THE AUS-TRALIAN REGION: CURRENT STATE OFKNOWLEDGESchaffelke, B. & Campbell, M. L.CSIRO Centre for Research on Introduced MarinePests, GPO Box 1538, Hobart, Tasmania 7001, Aus-tralia

Introductions of non-native macroalgae and the sub-sequent displacement of native species are globallybecoming more frequent. The algal genera Undaria,Sargassum, Caulerpa and Codium have been identifiedas being particularly invasive. An overview on thepresent knowledge on macroalgal introductions inthe Australian region is presented and options formanagement are discussed, mostly using examplesfrom studies on the introduced Japanese kelp,Undaria pinnatifida. Undaria pinnatifida was first de-tected in Tasmania, Australia in the early 1980’s.Since then, its range has expanded despite eradica-tion efforts. Long distance jumps appear to be the ma-jor mode of spread of U. pinnatifida in Tasmania.Studies are underway to distinguish the relative im-portance of spore dispersal, drift of adult plants andanthropogenic factors in spreading this invasive kelp.Although information on the real impacts of U. pin-natifida and other introduced macroalgae is sparse,the development of management and control strate-gies is of vital importance to prevent further spreadand translocation of these “pest” species.

182CONTRASTING LIFE HISTORIES ANDDEMOGRAPHIES OF LAMINARIAN ANDFUCOID ALGAESchiel, D. R.Zoology Department, University of Canterbury, Christ-church, New Zealand

Many species of large brown algae co-occur along si-milar shores and depths and seem to share similar eco-logical characteristics in terms of habitat-formation,providing nursery and feeding habitats for reef fish,vertical structure of habitats within the water columnand biomass production. However, the dominant spe-cies have very different life histories. Laminarianshave a heteromorphic alternation of generations,while fucaleans have an animal-like life history withmore direct development. Despite these differences,there seems to be no obvious relationship betweenlife history and ecological function. Laminarians andfucaleans seem generally to have very different de-mographies, with quite disparate features such aspropagule size and number, early survival, growthrates, and densities of plants required for a closed can-opy. Furthermore, few laminarians occur in the inter-tidal zone. Here, I will compare some species in thesegroups for which we know something about life his-tory and ecology in New Zealand and the USA. Al-though it is necessary to understand life histories ofindividual species to understand their demographyand ecological functions, this is not sufficient in itselfto predict such roles and functions.

183“SCATTERED CP-NUCLEOIDS” IN DIATOMSEXPLAINED: BACTERIA - INSIDE THE ENDO-PLASMIC RETICULUM - PIERCE THE PLAS-TIDS OF PINNULARIASchmid, A. M.Inst. f. Pflanzenphysiologie, Universität Salzburg, Hell-brunnerstr. 34, A-5020-Salzburg, Austria

Geitler’s (1937) observation on the regular perfora-tion of the chloroplasts of Pinnularia nobilis and thelack of a typical pyrenoid is supported using cy-tochemistry, and fluorescence & electron microscopy.Chloroplast cavities and channels harbour bacteria,their DNA elicit DAPI-fluorescence. Previous specula-tions on the DNA-positive, achromatic dots in theplastids of several Pinnularia species being “scatteredchloroplast nucleoids,” and the consequent separa-tion of diatom plastids in “primitive” and “advanced”types, are thus refuted. Bacteria are rod-shaped and assuggested by their TEM-profiles gram-negative pro-teobacteria. They occur inside the endoplasmic retic-ulum throughout the cell, in interphase prevailinglyin the space between the periplastidial membrane(PPM) and the CER membrane. Clusters of bacteriainside ER-cisternae near the nucleus in preprophase,and near the new plasmalemma after cleavage, indi-cates a cell-cycle dependent translocation within thediatom. Cavities in the plastids seem to be created by acombination of mechanical and chemical forces, inthe sequence: alignment, attachment, deformationand lysis, initially without an obvious disruption of thePPM and the chloroplast-envelope. Our future goal isto identify the bacteria and their metabolic function

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in the hereditary association with the plastids in Pin-nularia. Their intracellular, but extraplasmatic, loca-tion may reflect an ancestral constellation, and the ap-parent worldwide distribution may substantiate thisview.

184THE EFFECT OF SEAWEED DIETS ONGROWTH OF GREEN ABALONE, HALIOTISFULGENS, FROM BAJA CALIFORNIA, MEXICOServiere-Zaragoza, E.1, Mazariegos-Villareal, A.1& Ponce-Díaz, G.1,2

1Centro de Investigaciones Biológicas del Noroeste(CIBNOR). P.O. Box 128, La Paz, Baja CaliforniaSur. 23000. México; 2CICIMAR, IPN, La Paz, BajaCalifornia Sur México

Two abalone species: green Haliotis fulgens and yellowHalioti corrugata represent nearly 97% of the total pro-duction in the Mexican abalone fishery. It has beenassumed that abalone feed on the kelp algae Macrocys-tis pyrifera. Regional hatcheries use this species as amain source of natural food. M. pyrifera does not oc-cur at the southern limit of the distribution of aba-lone species along the Baja California Peninsula. Inthis study, growth rates of juveniles H. fulgens, 17.3 62.2 mm shell length and 0.4 6 0.2 g body weight, wereevaluated. Juveniles were fed with common species inthe benthic environments inhabited by abalone alongthe western coast of Baja California during 191 days.Three diets were based on algae: palm kelp, Eisenia ar-borea, giant kelp, M. pyrifera and Gelidium robustum,and one on seagrass, Phyllospadix torreyi. Shell lengthand body growth rates varied between 21.5 mm day21

and 2.2 mg day21 for E. arborea and between 45.9 mmday21 and 6.7 mg day21 for M. pyrifera. Higher specificgrowth rates (SGR) in length and weight were deter-mined for M. pyrifera: 0.2% and 0.7% day21. Signifi-cant differences between values of juveniles fed M. py-rifera with the rest of the diets were found. Thehighest mortality (21%) was in juveniles fed the redalgae G. robustum.

185A PROPOSAL FOR A NEW RED ALGALORDER, THE THOREALESSheath, R. G., Müller, K. M. & Sherwood, A. R.Department of Botany and Dean’s Office College of Bio-logical Science, University of Guelph, Guelph, ON,N1G 2W1, Canada

The freshwater red algal genera Nemalionopsis and Tho-rea are currently classified in the family Thoreaceae ofthe Batrachospermales. However, these two genera dif-fer from other members of the order in having multiax-ial thalli. The phylogenetic relationships of the gen-era were investigated using a combination of DNA

sequence analysis (rbcL and 18S rRNA genes) andtransmission electron microscopy. In both gene trees,Nemalionopsis and Thorea form well supported clades(87–100% bootstrap values) separate from other mem-bers of the Batrachospermales as well as taxa from theAcrochaetiales, Palmariales, and Nemaliales. In addi-tion, analysis of the secondary structure of the 18SrRNA gene in Nemalionopsis and Thorea reveals an ad-ditional helix, which is not present in any of the othertaxa within the Rhodophyta. Pit plugs of the Tho-reaceae also differ from those of other members ofthe Batrachospermales in not having an outer caplayer that is not universally domed. Based on thesefindings, it is proposed that Nemalionopsis and Thorearepresent a distinct taxonomic group that should berecognized as a new order, the Thoreales.

186SYSTEMATIC EVALUATION OF THE GENUSHILDENBRANDIA (RHODOPHYTA): A SYN-THESIS OF TECHNIQUESSherwood, A. R. & Sheath, R. G.Department of Botany and Dean’s Office, College of Bi-ological Science, University of Guelph, Guelph, ON,N1G 2W1, Canada

The evolutionary relationships among members ofthe red algal genus Hildenbrandia have not been wellunderstood for several reasons. For example, the ge-nus contains both marine and freshwater representa-tives, all of which are non-calcified and crustose, andfew have definitive morphological characters for clas-sification. Hildenbrandia is also assumed to be com-pletely asexual (reproduction by tetrasporangia inmarine forms and by gemmae in freshwater popula-tions), and characters of the female gametangial sys-tem and post-fertilization structures are not availablefor comparative studies. Currently there are 14 marineand five freshwater species and infraspecific taxa rec-ognized within the genus. We used phylogenetic anal-yses (parsimony, distance and maximum likelihood)of DNA sequences of commonly employed genes(rbcL and 18S rRNA) to examine the evolutionary re-lationships among representatives of many of thesetaxa. In addition, we employed morphometrics (prin-cipal co-ordinates and cluster analyses) of severalmeasured characters of these same representatives, aswell as all available type specimens, to determine thenumber of morphologically-delimited entities withinthe genus. Thus far our results indicate that somecharacters traditionally used to distinguish species ofHildenbrandia, such as tetrasporangial division pat-tern, may not be useful in some cases, and a revisionof the taxonomy of the genus will be necessary. Al-though the marine and freshwater species of Hilden-brandia appear to be well separated in our molecularanalyses of European specimens, this trend was notobserved for North American specimens. High se-

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quence divergence values were calculated for boththe rbcL and 18S rRNA genes of Hildenbrandia, com-pared to other red algal genera.

187GEOGRAPHICAL CORRELATION OF MOR-PHOLOGICAL VARIATION IN SILVETIA COM-PRESSA (FUCACEAE, FUCALES, PHAEO-PHYCEAE)Silva, P. C.1, Pedroche, F. F.1,2, Chacana, M. E.1,Aguilar Rosas, L. E.3, & Aguilar Rosas, R.41University Herbarium, University of California, Ber-keley, CA 94720-2465 USA; 2Depto. de Hidrobiología,Universidad Autónoma Metropolitana-Iztapalapa, Apdo.Postal 55-535, México, D.F. 09340, México; 3Institutode Investigaciones Oceanológicas, Universidad Au-tónoma de Baja California, Apdo. Postal 453,Ensenada, Baja California, México; 4Facultad deCiencias Marinas, Universidad Autónoma de BajaCalifornia, Apdo. Postal 453, Ensenada, Baja Califor-nia, México

Silvetia compressa (J. Agardh) Serrão et al. is a commonmember of the upper intertidal fucoid community onthe Pacific coast of America from Humboldt County,California, to Punta Baja, Baja California, Mexico. Arelatively narrow range of morphological variability isexhibited by most mainland populations, regardlessof latitude, but some mainland populations and all in-sular populations participate in a complex patternthat we have attempted to analyze. A few populationson the Monterey Peninsula in which the fronds areatypically delicate were described by Setchell & Gard-ner as f. gracilis, to which was assigned a populationfrom Santa Catalina Island. After comparing popula-tions from various parts of the range of the species, in-cluding all of the Channel Islands, we conclude thattwo subspecies may be recognized. In subsp. compressa,which includes f. gracilis as a growth form and occurschiefly on the mainland, the frond is robust with longtapered receptacles. In the variant subspecies, whichis chiefly insular but also occurs on the coast of north-ern Baja California, the typical frond has slender axesas in f. gracilis, but is more densely branched and hasshort ellipsoidal receptacles. Comparison of nucle-otide sequences from the ITS regions of rDNA re-vealed an identical pattern for subsp. compressa fromBaja California and central California, including pop-ulations assignable to f. gracilis. By contrast, the pat-tern for the variant subspecies differed by 2 bp (0.3%)from that of subsp. compressa.

188THE DISTRIBUTION AND ABUNDANCE OFDEEPWATER MACROALGAE IN CENTRALCALIFORNIASpalding, H. L.

Moss Landing Marine Laboratories, 8272 Moss Land-ing Rd., Moss Landing, CA 95039 USA

Deepwater macroalgal assemblages (DWAAS) weresampled from 30m to their lower depth limits at 4 lo-cations in central California using enriched air Ni-trox and the ROV Ventana. The lowest observeddepth limits were 78 m for nongeniculate (encrust-ing) coralline algae, 58 m for non-calcified red algae(i.e. Maripelta rotata), 40 m for foliose brown algae(i.e. Desmarestia tabacoides), and 37 m for kelps (i.e.Pleurophycus gardneri). Green algae, such as Derbesiamarina and an undescribed deep water species of Co-dium, were observed at 30m, while large patches of anunknown green or blue-green algal film of coccoidcells were found from 45 to 48 m. DWAAS zonationwas generally similar to that in southern California,with subtle differences in the zonation of foliose redalgae and the occurrence of an unknown Chloro-phyta or Cyanophyta from 45–49m. Twenty four spe-cies of algae (13 Rhodophyta, 11 Phaeophyta) weresampled during the percent cover analysis at 30 m.Nongeniculate corallines varied from 53% to 91%cover depending on location, while geniculate coral-lines (i.e. Bossiella schmittii) averaged ca. 25% cover.Pleurophycus gardneri, a stipitate kelp previously de-scribed as “rare” in central California, was the mostabundant brown alga, averaging from 2.68 to 4.8 indi-viduals m22. Algal abundance (percent cover and den-sity), zonation, and light levels at the lower algaldepth limits were similar between sites and locations,suggesting that the environment of deep water algalpopulations in this region is less variable than that ofthe shallow water kelp forest communities abovethem.

189POPULATION PARAMETERS AND PHOTO-SYNTHETIC CAPABILITIES OF CORALLINERHODOLITHS: BIOGEOGRAPHIC IMPLICA-TIONSSteller, D. L.1, Cabello-Pasini, A.2 & Riosmena-Rodriguez, R.31Biology Department, University of California-SantaCruz, Santa Cruz, CA 95064 USA; 2Instituto de Inves-tigaciones Oceanológicas, Universidad Autónoma deBaja California, A.P. 453, Ensenada, Baja California22800, Mexico; 3Dept. Biología Marina, UniversidadAutónoma de Baja California Sur, A.P. 19B, La Paz,Baja California Sur, Mexico

Rhodoliths are bed forming, unattached coralline al-gae that incorporate large quantities of carbonateinto their thalli in oceans worldwide. Lithophyllum mar-garitae and Neogoniolithon tricotomun are commonRhodoliths from the Gulf of California, however, littleis known about their biogeographic distribution, andtheir ecological and physiological characteristics. As a

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consequence, the objective of this study was to definethe temporal population dynamics, growth rates andphotosynthetic capabilities of L. margaritae and N. tric-otomun from the Gulf of California. The Gulf ofCalifornia is characterized by annual temperaturefluctuations that can exceed 208 C. Rhodolith beds ex-ceeding one km in length were observed from theintertidal zone to a depth of approximately 20 m atthe southern Gulf. Percent cover estimates for spheri-cal unattached individuals of L. margaritae and N. tric-otomun ranged from 10 to 100%. Growth rates weredetermined by staining the rhodoliths with Alizarinered and evaluating the linear increment of calciumcarbonate after an incubation period in the field. An-nual growth rates averaged 1.8 mm year21 in L. marga-ritae and 3.4 mm year21 in N. tricotomun, however,growth rates varied seasonally. The photosynthetic re-sponse of both species as a function of temperaturewas evaluated in the laboratory from 108 to 308 C.Maximum net photosynthetic rates peaked at approx-imately 25 to 308 C in both species, suggesting thatmaximum growth rates occur during the warmestmonths of the year. These results lead to a better un-derstanding of the biogeographic ranges of subtidalcoralline algae.

190SYMBIOTIC ORIGIN OF A NOVEL ACTINGENE IN THE CRYPTOPHYTE, PYRENOMO-NAS HELGOLANDIIStibitz, T. B.1, Keeling, P. J.2, & Bhattacharya, D.11Department of Biological Sciences, University of Iowa,Iowa City, IA 52242 USA; 2Department of Botany,University of British Columbia, Vancouver, BC V6T1Z4 Canada

Cryptophytes are photosynthetic protists that have ac-quired their plastids through the secondary symbioticuptake of a red alga. A remarkable feature of crypto-phytes is that they maintain a reduced form of the redalgal nucleus, the nucleomorph, between the secondand third plastid membranes (periplastidial compart-ment, PC). The nucleomorph is thought to be a tran-sition state in the evolution of secondary plastids withthis genome ultimately being lost (e.g., as in heter-okonts, haptophytes, euglenophytes) when photosyn-thesis comes under full control of the “host” nucleus.For this to happen, all genes for plastid function mustbe transferred from the nucleomorph to the nucleus.In this regard, it is generally assumed that nucleo-morph genes with functions unrelated to plastid orPC maintenance are lost. Surprisingly, we show herethe existence of a novel type of actin gene in the hostnucleus of the cryptophyte, Pyrenomonas helgolandii,that has originated from the nucleomorph genome ofthe symbiont. Our results demonstrate for the firsttime that secondary symbionts can contribute genesto the host lineage that are unrelated to plastid func-

tion. These genes are akin to the products of gene du-plication and provide a source of evolutionary noveltythat could significantly increase the genetic diversityof the host lineage. We postulate that this may be acommon phenomenon in algae containing secondaryplastids that has yet to be fully appreciated due to adearth of evolutionary studies of nuclear genes inthese taxa.

191THE EVOLUTION OF RNA POLYMERASE IIIN RED ALGAEStiller, J. W., Riley, J. L., & Hall, B. D.Departments of Genetics and Botany, University ofWashington, Seattle, WA 98195 USA

Whether red algae are the sister group to green plantshas been an intriguing question for over a century.We are investigating both the evolutionary and func-tional significance of differences in DNA-dependentRNA polymerase II between rhodophytes and othereukaryotic organisms. Results of both phylogeneticand genetic complementation studies are consistentwith an origin of the Rhodophyta that was indepen-dent of the common ancestor of green plants, ani-mals, fungi and several related protistan groups. Ex-amination of long-branch attraction among Pol IIgene sequences indicates that this separate emer-gence of red algae is not the result of an artifactualgrouping of rhodophytes with more rapidly evolvingtaxa. The absence in red algal pol II largest subunitsof a canonical C-terminal domain (CTD), an essentialcomponent of mRNA transcription in plants, animalsand fungi, further supports the proposition that redalgae diverged independently of these groups, and be-fore CTD function was incorporated fully into Pol IIfunction. Evolutionary complementation, that is, invivo replacement of the wild-type CTD from yeast withRPB1 C-terminal sequences from a red alga, furthersupports the hypothesis that fundamental differencesexist in Pol II function between red algae and organ-isms with a CTD-based mRNA transcription cycle.

192BIOCHEMISTRY OF SILICA BIOMINERAL-IZATION IN DIATOMSSumper, M.Department of Biology, University of Regensburg,93040 Regensburg, Germany

Diatoms are well known for the intricate patterns oftheir silica-based cell walls. The complex structures ofdiatom cell walls are species specific and become pre-cisely reproduced during each cell division cycle, indi-cating a genetic control of silica biomineralization.Therefore, the formation of the diatom cell wall hasbeen regarded as a paradigm for controlled produc-tion of nanostructured silica. However, the mecha-

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nisms allowing biosilicification to proceed at ambienttemperature at high rates have remained enigmatic.Recently, we have shown that a set of highly cationicpeptides (called silaffins) isolated from Cylindrothecafusiformis shells are able to generate networks of silicananospheres within seconds when added to a solutionof silicic acid. Different silaffin species produce differ-ent morphologies of the precipitated silica. Silaffinscontain covalently modified Lys-Lys elements. One ofthese lysine residues bears a novel type of proteinmodification, a polyamine consisting of 6–11 repeatsof the N-methyl-propylamine unit. In addition to thesilaffins, additional polyamine-containing substanceshave been isolated from a number of diatom speciesthat may be involved in the control of biosilica mor-phology. Scanning electron microscopic analysis of di-atom shells isolated in statu nascendi provide insightsinto the processes of pattern formation in biosilica. Amodel will be discussed that explains production ofnanostructured biosilica in diatoms on the basis ofthese experimental results.

193EFFECTS OF INCREASING UV-B RADIATIONDUE TO OZONE DEPLETION ON PHOTO-SYNTHESIS OF ANTARCTIC CYANOBAC-TERIATang, E. P. Y., Neale, P. J. & Fritz, J. J.Smithsonian Environmental Research Center, P. O.Box 28, Edgewater, MD 21037 USA

Ground level ultraviolet-B (UV-B; 290–320 nm) fluxesin Antarctica have been increasing due to strato-spheric ozone depletion. Although mat-forming cy-anobacteria are major component of freshwater algalbiomass in Antarctica, little is known about their re-sponse to increasing ultraviolet radiation (UVR). Thepresent study evaluated the sensitivity to UVR of twostrains of mat-forming cyanobacteria with differentcell size, Phormidium murrayi (6.0 x 3.2 mm) and Schizo-thrix calcicola (2.2 x 2.3 mm). Cyanobacterial photosyn-thesis was measured under different UV spectral qual-ity and quantity achieved by polychromatic filters withdifferent cutoff wavelengths and neutral densityscreens. The productivity and irradiance data wereused to generate biological weighting functions(BWF) for the assessment of UV inhibition on photo-synthesis. The kinetics of UV inhibition, as deter-mined by PAM fluorometry, differed between the twospecies so that inhibition of P. murrayi and S. calcicolawere modeled based on UV-irradiance and cumula-tive exposure, respectively. After a one hour expo-sure, BWF’s did not differ between the two isolates ofcyanobacteria despite their differences in cell size. Toevaluate the negative impact of increased UV-B expo-sure due to ozone depletion on cyanobacteria, theBWF’s were applied to two solar spectra obtainedfrom McMurdo Station, one on a day when the ozone

hole was prominent (O3 5 170 Dobson units; DU 510-3 cm O3), and the other on a day with high ozoneconcentration (O3 5 328 DU). The decrease in ozonelevel would reduce productivity by 3–8%. Seasonalvariation of UVR has a bigger impact on cyanobacte-rial productivity than ozone depletion.

194ANALYSIS OF PORPHYRA RBCL DEMON-STRATES MULTIPLE MIGRATIONS OC-CURRED BETWEEN THE NORTH ATLANTICAND NORTH PACIFIC.Teasdale, B. W.1, Lindstrom, S. C.2, Fredericq,S.3, Neefus, C. D1., Mathieson, A. C.1 Taylor, H.4 ,West, A.L.5, Mercado, S. T.4, Piche, N.4, & Klein,A. S.4,5

1Department of Plant Biology, University of NewHampshire, Durham NH 03824 USA; 2 Department ofBotany, University of British Columbia, Vancouver,B.C. V6T 1Z4 Canada; 3Department of Biology, P.O.Box 42451 University of Louisiana at Lafayette Lafay-ette LA 70504 USA; 4Department of Biochemistry and-Molecular Biology, University of New Hampshire,Durham NH 03824 USA; 5Genetics Program, Univer-sity of New Hampshire, Durham NH 03824 USA

The taxonomic and evolutionary relationships be-tween Porphyra of the boreal North Pacific (NP) andNorth Atlantic (NA) are being examined using nearfull length sequences of rbcL and the rbcL rbcS spacer(z1420 bp). Phylogenetic analysis of .20 recognizedspecies produced clusters containing both NP and NAspecies: Porphyra carolinenesis (NA) and Porphyra perfo-rata (NP); Porphyra. leucosticta (NA) and Porphyra fuci-cola (NP); Porphyra ‘amplissima’ (NA) and Porphyra cu-neiformis (NP); Porphyra ‘umbilicalis’ (NA) and Porphyramumfordii (NP). A cluster of NP species including Por-phyra abbottae, Porphyra kurogii, Porphyra pseudolinearis,and Porphyra pseudolanceolata formed a sister clade toP. fucicola (NP), P. leucosticta (NA) and several crypticNA taxa. These results demonstrate that a number of“independent” migrations occurred between theNorth Pacific and Northern Atlantic. Furthermorethese results confirm the hypothesis, based on similar-ities in morphology, isozymes, and karyotype, of Lind-strom & Cole (1992), that several sibling species pairsexist for Porphyra of the boreal North Pacific (NP) andNorth Atlantic (NA).

195LIGHT REGULATION OF PHYCOBILISOMEBIOSYNTHESIS AND CONTROL BY A PHY-TOCHROME-LIKE PHOTORECEPTORTerauchi, K.1, Ort, L.1, Grossman, A. R.2, &Kehoe, D. M.11Department of Biology, A413 Jordan Hall, 1001 EastThird Street, Indiana University, Bloomington, IN

66 PSA ABSTRACTS

47405 USA; 2Department of Plant Biology, CarnegieInstitution of Washington, 290 Panama Street, Stan-ford, CA 94305 USA

Ambient light quality changes dramatically affect thecomposition of light harvesting structures, the phyco-bilisomes, in many cyanobacterial species. In the cy-anobacterium Fremyella diplosiphon, shifts in the ratioof red to green light lead to transcriptional changesand altered synthesis of several phycobilisome compo-nents. This process is called complementary chro-matic adaptation (CCA). These two colors have oppo-site effects: red light activates an operon encoding thebiliprotein phycocyanin (PC) and inactivates the op-eron encoding phycoerythrin (PE), whereas greenlight activates PE synthesis and shuts down PC synthe-sis. The effects of red and green light on CCA arephotoreversible. Thus, CCA is similar to transcrip-tional processes that are controlled by phytochromes,a family of eukaryotic red/far red photoreversiblephotoreceptors. We are using molecular genetics todetermine the mechanisms by which F. diplosiphonsenses changes in the color of light of its environ-ment. Initial mutant generation and complementa-tion lead to the discovery of three CCA regulatorycomponents that are part of a complex two compo-nent system. The most interesting of these is RcaE(regulator of chromatic adaptation), a histidine ki-nase-class protein containing a region in its amino-ter-minal half with similarity to the chromophore bindingdomains of phytochromes. Within this region, RcaEcontains a cysteine residue in a similar location as thatused for covalent attachment of the open-chain tet-rapyrrole chromophore in phytochromes. We willpresent recent data characterizing RcaE, including invivo analysis of the chromophore that is attached toRcaE, as well as results from our recent isolation of anew CCA regulatory component.

196WHAT DOES COMBINING MOLECULAR DATASETS TELL US ABOUT DIATOM ORIGINSAND PHYLOGENY?Theriot, E. C.1 & Goertzen, L.21Texas Memorial Museum, 2400 Trinity Street, Uni-versity of Texas, Austin, TX 78705 USA; 2Section ofIntegrative Biology, University of Texas, Austin, TX78712 USA

The past several years have seen an abundance of mo-lecular sequence data gathered on heterokont algaeand other stramenopiles with the goal of resolvingphylogenetic relationships among major groups. Theoriginal focus was on SSU rDNA sequence, but lately asignificant number of sequences of plastid and mito-chondrial encoded genes (specifically rbcL and coxI)have been made available. Of particular interest to ushas been the origin of diatoms and the relationship of

diatoms to other stramenopiles. According to mostclaims based on morphological data, typically viewedfrom a non-rigorous evolutionary taxonomy stand-point (i.e. not with explicit cladistic or phylogeneticsystematic methodology), diatoms are closely relatedto silica-scaled golden brown algae (chrysophytes orsynurophytes). SSU rDNA sequence data, however, of-ten place diatoms at the base of the heterokont algatree, and chryso/synurophytes at the tip with eustig-matophytes, for example, as the chryso/synurophytesister group. More recent analysis of rbcL sequences,however, supports the traditional classification. It isnot automatically to be assumed that there is incon-gruence between the sequences, however. Taxon sam-pling is different in the different analyses, methods ofanalysis are often different, assumptions used to “fil-ter” data are different, etc. Moreover, the relativestrength of signal appears to be different in the datasets. We will present an analysis of combined SSU,rbcL and coxI data, an analysis of taxon-sampling is-sues, and review underlying assumptions and method-ologies in an attempt to a) better understand the re-sults of prior studies and b) reconcile the differenthypotheses.

197PHYLOGENETIC RELATIONSHIPS OF GELID-IALES SPECIES IN COSTA RICAThomas, D. T. & Freshwater, D. W.Center for Marine Science, University of North Caro-lina at Wilmington, 1 Marvin Moss Lane, Wilming-ton, NC 28409

Despite a general paucity of studies on marine algaein Costa Rica, within the red algal order Gelidiales, 9species are reported from the Caribbean, and 6 spe-cies from the Pacific. In this study 5 species from thesoutheast Caribbean coast and 2 species from thenorthwest Pacific coast of Costa Rica were collectedfor DNA sequence and morphological analyses. At thetime of this writing, morphological observations offour Caribbean taxa have identified them as Gelidiummicrodonticum, Pterocladiella capillacea, P. melanoidea,and Gelidiella acerosa. In rbcL sequence analyses, Gelid-ium microdonticum is resolved within a clade of smallGelidium species predominantly found in the south At-lantic. Two collections representing different forms ofPterocladiella melanoidea sensu Dawson were found tohave identical rbcL sequences. These samples were re-solved in rbcL trees with a taxon from Texas identifiedas P. bartlettii and not P. melanoidea from Europe. Com-parisons with type material are being made to verifythese identifications so that the status of P. melanoideain the Caribbean may be determined. The unidenti-fied Caribbean taxon is resolved as a distinct specieswithin the Pterocladiella clade as well. Gelidiella acerosafrom Caribbean Costa Rica is closely allied with otherCaribbean G. acerosa samples in rbcL trees. The two pa-

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cific taxa are small intertidal turf species and have notyet been identified. Sequence analyses resolve thesetaxa within a large clade of Indo-Pacific and Carib-bean Gelidium species.

198DIATOMS AS HOSTS FOR OTHER DIATOMS:OBSERVATIONS FROM SOUTHERN CALI-FORNIATiffany, M. A.1, & Lange, C. B.21Department of Biology, San Diego State University,San Diego, CA 92128 USA; 2Scripps Institution ofOceanography, La Jolla, CA 92093-0244 USA

Large epiphytic and epilithic diatom species hostingother diatoms were observed in several fresh- andbrackish water sites in Southern California. The mostcommonly encountered hosts were species forminglong filaments attached to rocks or macroalgae, Hy-drosera whampoensis (Schwarz) Hendey, Melosira vari-ans Agardh, Pleurosira laevis (Ehrenberg) Compereand Terpsinoe musica Ehrenberg. These large diatomsoften had smaller diatoms attached, usually to the gir-dle bands and occasionally to the mucilage pads con-necting the cells. For example, cells of T. musica wereobserved supporting growth of a diverse diatom as-semblage composed of species of the genera Achnan-thes, Achnanthidium, Amphora, Cocconeis and Tabularia;Synedra sp. was attached to M. varians and B. paxillifer;and Cocconeis placentula was seen on H. whampoensis.Thus, large epiphytic and epilithic diatoms seem toprovide suitable sites for attachment of small epi-phytic diatom species, and it appears that this phe-nomenon is more common than previously thought.

199ASSOCIATION OF A FREE-LIVING EUGLENAWITH A COLONIAL ROTIFERUzwiak, D. J. & Triemer, R. E.Division of Life Sciences, Rutgers University, Piscat-away, NJ 08854 USA

Euglena agilis (syn. Euglena pisciformis) is a free-livingeuglenoid found in brackish or fresh water. This spe-cies can be identified by its fusiform shape, singlelong flagellum, and prominent anterior eyespot. Itcan be distinguished from other euglenoids in part byits two to three large chloroplasts that run parallel tothe length of the body, each with a single pyrenoidcapped on two sides by paramylon. Euglena agilis iscommonly found in our collecting ponds in centralNew Jersey. In two consecutive summers, we havefound large numbers of these cells living symbiotically

with the colonial rotifer Conochilus unicornis. We donot know if either organism benefits or is harmed inthis relationship. For example, while we’ve seen therotifers of the colony ingest other algae, we have notseen predation of the E. agilis (neither those embed-ded in the mucilaginous secretions of the rotifer norswimming outside of the colony). This association isinteresting for several reasons: 1) E. agilis is normallyfree-living. 2) There are few known symbiotic relation-ships between euglenoids and rotifers. 3) E. agilis losetheir long single flagellum when in the colony. Weplan to use light and electron microscopy to investi-gate the ultrastructure of the E. agilis and its relation-ship to the rotifer colony.

200EVIDENCE FOR GLUCAN COMPONENTS INTHE PRIMARY ZYGOTE WALL OF CHLAMY-DOMONAS MONOICAVanWinkle-Swift, K. P., Salanga, M. C., Thompson,E. G., Bai, M. S., & Parish, E. W.Department of Biological Sciences, Northern ArizonaUniversity, Flagstaff, AZ 86011

The primary zygote wall of C. monoica is transient andis released from mature zygospores. The fluoro-chromes aniline blue and primulin, used in other sys-tems to detect b-1,3 glucans, stain the primary wall in-tensely. Two b-1,3 glucan synthases have beenidentified in higher plants: a calcium-dependent syn-thase produced in response to wounding and inducedby chitosan, and a magnesium-dependent enzyme, as-sociated with pollen development and unresponsiveto chitosan. Chitosan has no effect on C. monoica pri-mary wall synthesis or staining properties. We arepresently testing for the effect of magnesium and/orcalcium depletion on primary wall synthesis. Anilineblue and primulin do not stain purified cellulose fi-bers, while the fluorochrome Calcofluor does. Calcof-luor also stains the primary wall intensely. For all fluo-rochormes tested, fluorescence is first detected inmotile quadriflagellate zygotes. Aniline blue stainingmaximizes quickly, while Calcofluor staining contin-ues to intensify until primary wall release. Dinitroben-zonitrile, a specific inhibitor of cellulose synthesis inplants, has no effect on primary wall synthesis in C.monoica. Addition of glucanase or cellulase to partiallypurified primary walls results in wall thinning and lossof staining. Using electron microscopy, we are evaluat-ing the effects of these enzymes on primary wall ultra-structure. Further studies are needed to determinewhether all three fluorochromes are recognizing thesame polysaccharide component (a b-1,3 glucan or ab-1,3; b-1,4 mixed glucan), or whether Calcofluorstaining indicates the presence of a distinct compo-nent containing b-1,4 linkages, such as cellulose or axyloglucan.

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201SURVEY OF BENTHIC DIATOM COMMUNI-TIES FROM LOTIC SYSTEMS WITHIN THEWESTERN ALLEGHENY PLATEAUVerb, R. G. & Vis, M. L.Department of Environmental & Plant Biology, OhioUniversity, Athens, OH 45701 USA

Over the course of 3 years (1997–1999), 72 streamsites were sampled for epilithic diatom communities.The analysis of these samples has led to the identifica-tion of over 325 species of diatoms. In addition tosampling the diatom community, selected physicaland chemical parameters were recorded from eachstream reach. These parameters included pH, specificconductance, current velocity, SRP, nitrate, silica, andtotal alkalinity. Canonical Correspondence Analysis(CCA) was used to identify influential environmentalparameters and to assess the response of the diatomcommunity to prominent anthropogenic inputs in theregion (i.e. coal mine drainage, eutrophication). Theinitial analyses indicate that pH was the most influen-tial environmental parameter along the first CCA axis.This shift was not unexpected, as acid mine drainage(AMD) in the region leads to a wide range of pH val-ues (2.8–7.93). The highly acidic sites were character-ized by species of the genus Eunotia (specifically E. ex-igua and E. steineckei), Frustulia rhomboides, and Pinnulariasubcapitata. Furthermore, Achnanthidium minutissimumwas the most widely distributed of the diatom speciesencountered, being found at 94% of the sites sam-pled. Streams that fluctuated between acidic and cir-cumneutral pH (termed “teeter-totter”) had greaterabundances of Brachysira vitrea than other streams inthis survey. Further implications for the use of thesediatom communities as biomonitoring tools and thedistribution of assemblages within the Western Al-legheny Plateau will be discussed.

202BIOGEOGRAPHY OF BATRACHOSPERMUMHELMENTOSUM (BATRACHOSPERMALES,RHODOPHYTA) IN NORTH AMERICA USINGMOLECULAR AND MORPHOLOGICAL DATAVis, M. L., Miller, E. J., & Hall, M. M.Department of Environmental & Plant Biology, OhioUniversity, Athens, OH 45701 USA

Twelve collections of the freshwater red alga Batracho-spermum helmentosum were investigated using molecu-lar sequence and morphological data. Collectionswere from streams throughout the range of this spe-cies in North America, from Louisiana and Tennesseein the south to Michigan and Massachusetts in thenorth. Eleven morphometric characters were mea-sured for each of the specimens sequenced. Both the

rubisco large subunit gene (rbcL) and the ribosomalDNA internal transcribed spacers (ITS1 & 2) were se-quenced. Morphometic results showed individualsfrom the various locations to be morphologically uni-form with little variation in pertinent characters. Inthe analysis of the rbcL data, samples from Connecti-cut, Ohio, Louisiana, North Carolina and Indianawere identical in sequence and the Rhode Island andMassachusetts samples were most derived. The Michi-gan and Tennessee samples were closely related toeach other but not the other samples. For the ITSdata, the tree topology was similar to that obtainedwith the rbcL data. In comparison with rbcL, sequencevariation in the ITS region among samples wasgreater and showed more resolution among thestream sites. In terms of biogeography, three geo-graphically close samples (Connecticut, Rhode Is-land, Massachusetts) were most closely related. How-ever, genetic relationships did not necessarily reflectgeographic distance. For example, two distant popula-tions, Louisiana and Indiana, were most closely re-lated. Variation in ITS sequence data among individu-als from a single stream site will be discussed.

203THE PHYLOGENETICS OF ACROCHA-ETIALES REVISITED: INFERENCES FROMRBCL AND CHLOROPLAST ENCODED 23SRRNA SEQUENCE ANALYSISVolovsek, M. E.1, Hommersand, M. H.1, &Manos, P.2Department of Biology, 1University of North Carolina,Coker Hall, Chapel Hill, NC 27599 USA; 2Departmentof Botany, Duke University, Durham, NC 27708 USA

Recent molecular evidence from 23S rRNA sequenceshas shed light on the phylogenetic status of Acrocha-etiales and Palmariales, suggesting a paraphyletic Ac-rochaetiales and a monophyletic Palmariales-Acrocha-etiales assemblage characterized by the absence ofboth the carpogonial filament and associated post-fer-tilization fusions. It has also brought into question thestatus of Palmariales. Despite these findings, the fa-milial and generic systematics of Acrochaetiales haveremained somewhat obscure, in large part due to in-adequate taxon and gene sampling. In the presentstudy we address this problem by performing phyloge-netic analyses of rbcL and 23S rRNA sequences fromacrochaetioid algae covering a broad range of mor-phologies. Our results confirm elements from severalprimarily chloroplast based classification schemes(Papenfuss 1945, 1947; Stegenga 1979, 1985; Lee &Lee 1988) while also providing new phylogenetics in-sight. Two groups are supported at the most inclusivelevel. Group I is marine, has parietal chloroplasts, andincludes three clades delimited primarily by the pres-ence/absence of pyrenoids, number of chloroplasts,

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and possibly spore germination pattern. Group II ismore heterogeneous and consists of three clades dif-ferentiated largely by chloroplast type (stellate/pari-etal, pyrenoid present/absent) and number, habitat(marine/freshwater) and life history. Systematic crite-ria drawn from the closely related order Palmarialessuggest that we recognize Group I as a new family, Co-laconemataceae, and the three taxa in Group II as Ac-rochaetiaceae, Rhodochortonaceae and Audouinel-laceae. Furthermore, each of the three groups inColaconemataceae could be regarded at the genericlevel. We also report on the utility of 23S rRNA for redalgal systematics.

204THE ROLE OF CALCIUM IN FLOW-STIMU-LATED BIOLUMINESCENCE OF THE REDTIDE DINOFLAGELLATE LINGULODINIUMPOLYEDRUMvon Dassow, P., & Latz, M. I.Scripps Institution of Oceanography, University of Cal-ifornia San Diego, La Jolla, CA 92093 USA

Many marine planktonic dinoflagellates emit flashesof light in response to either laminar or turbulentflows as well as direct mechanical stimulation. Theproduction of a flash of light is known to be mediatedby a proton-mediated action potential across the vacu-olar membrane; the mechanotransduction processinitiating this action potential is unknown. Here wereport on an investigation into the role of Ca12 in themechanotransduction process regulating biolumines-cence in the red tide dinoflagellate Lingulodinium poly-edrum. Calcium ionophores and low concentrations ofthe membrane-disrupting agent digitonin stimulatedbioluminescence only when calcium was present inthe media or added with the agent, indicating that theflash-triggering vacuolar action potential is specifi-cally stimulated by a calcium influx. A variety ofknown calcium channel blockers or antagonists inhib-ited mechanically stimulated bioluminescence but didnot affect cellular bioluminescent capacity. In manycases the inhibitory affect occurred after only a briefexposure. In addition, gadolinium (Gd13), a blockerof many stretch-activated ion channels, caused potentinhibition of mechanically stimulated biolumines-cence. The order of potency of the transition metalstested was La13 . Gd13 . Co12 . Mn12 . Ni12, si-milar to their potency as blockers of known calciumchannels. Experiments with a quantified shear flowdemonstrated that flow-stimulated bioluminescencedepended on the level of extracellular calcium. Fu-ture work will elucidate the signaling pathway involv-ing calcium-mediated flow-stimulated mechanotrans-duction. Our goal is to use bioluminescence as aproxy for the initial cellular mechanotransductionevents triggered by fluid flow.

205TEMPERATURE INDUCED PHOTOINHIBI-TION IN OUTDOOR CULTURES OF MONO-DUS SUBTERRANEUSVonshak A.1, Torzillo, G.2, & Boussiba S.11Microalgal Biotechnology Laboratory, The JacobBlaustein Institute for Desert Research, Ben-GurionUniversity of the Negev, Sede Boker Campus 84990, Is-rael; 2Centro di Studio dei Microrganismi Autotrofi delCNR, Firenze, Italy

Outdoor algal cultures are continuously exposed tochanges in environmental conditions, particularly ir-radiance and temperature. While the changes in lightintensity take place in a range of one to two hours, theincrease in temperature is a slower process and takesabout four to five hours. This de-synchronization be-tween the two important environmental factors gov-erning photosynthesis and growth of algae results in aunique stress condition where photoinhibition can beinduced at relatively low light intensity. Outdoors theearly morning culture temperature was found to beabout 12 to 148 C, and reaches 25 to 288 C at mid-day.In an experiment, such a natural temperature regimewas compared to another one in which the morningtemperature of the culture was increased to 208 C byusing a heating system. A fast decline in the maximalphotochemical efficiency of PSII (Fv/Fm) was ob-served starting as soon as sunrise. The decline wasfaster in the non-heated culture and was to a lowervalue. The diurnal changes in the electron transferrate (ETR) and in the non-photochemical quenching(NPQ) of the cultures, indicated that the early morn-ing exposure of cells to sub-optimal temperature re-sults in a fast inactivation of PSII activity which was re-flected in an inhibition of the photosynthetic activityeven when the two cultures finally reached the sametemperature at mid-day. Thus, under the same lightand temperature mid-day conditions the ETR washigher and the NPQ was significantly lower in theheated culture. Significant changes in productivity ofthe cultures also were observed.

206FUCUS VANADIUM PEROXIDASE: MINIMUMCATALYTIC DOMAIN SIZE RETAINING PER-OXIDASE ACTIVITYVreeland, V. J., Ly, L. S., Riebe, J. L. Sabatier, C.& McCoy, S. I.Materials Sciences Division, Lawrence Berkeley Na-tional Laboratory, MS 66, 1 Cyclotron Road, Berkeley,CA 94720 USA

Vanadium peroxidase catalyzes the extracellular as-sembly of Fucus zygote cell surface adhesive (Vreeland& Epstein 1996, Modern Meth. Plant Anal. 17, 95–116).Our goal is to identify the catalytic, self-associating

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and wall targeting functional domains of algal vana-dium peroxidase to understand its role in algalpropagule adhesion. As a first step, we truncated ourrecombinant Fucus vanadium peroxidase (GenBankAF053411) for catalytic domain identification. Re-combinant constructs were prepared which re-duced the C-terminal catalytic domain at either or‚oth N- and C-terminal ends. Recombinant proteinswere expressed in E. coli, refolded from cytoplasm andinclusion ‚odies and tested for vanadium-specific o-dianisidine peroxidase activity. Preliminary resultsdemonstrated peroxidase activity when the 40 kDacatalytic domain was truncated on ‚oth ends to 24kDa. Further terminal and internal truncation isneeded to fully define the minimal catalytic unit,which could be as small as 15–20 kDa within the 73kDa monomer. The very small catalytic unit in Fucusvanadium peroxidase is not unexpected consideringthe rigid ‚undled helical vanadate frame in the Cur-vularia fungal vanadium peroxidase (Macedo-Ribeiroet al. 1999, J. Biol. Inorg. Chem. 4, 209–219). We con-clude that interactions ‚etween the N-terminal non-catalytic domain and the C-terminal catalytic domain,found in the crystalline Ascophyllum enzyme (Weylandet al. 1999, J. Mol. Biol. 293, 595–611), are unnecessaryfor peroxidase activity. Other conserved amino acidsin the C-terminal half of Fucus vanadium peroxidase,peripheral to the helical core, could participate inprotein surface functions such self-association andwall targeting.

207DIATOM SILICA BIOMINERALIZATION: ATNANOSCALE LEVEL A CHEMICALLY UNI-FORM PROCESSVrieling, E. G.1, Gieskes, W. W. C.1, Beelen, T. P. M.2,& van Santen, R. A.21Department of marine Biology, University of Gronin-gen, P.O. Box 14, NL-9750 AA Haren, The Nether-lands; 2Schuit Institute of Catalysis, Eindhoven Uni-versity of Technology, P.O. Box 513, NL-6500 MB,The Netherlands

Using a high-brilliance synchrotron X-ray source,combined small- and wide-angle X-ray scattering(SAXS and WAXS) was applied to study nanoscalecharacteristics, in particular pore size in the range of3 to 65 nm, of a variety of unialgal cultures of centricand pennate diatoms, and of mixed diatom popula-tions sampled in the field. Results of scattering analy-sis were compared with details of pore size, structureand orientation visible at the electron microscopiclevel. WAXS patterns did not reveal any crystallinephase or features of microcrystallinity (resolution 0.07to 0.51 nm), which implies a totally amorphous char-acter of the SiO2 matrix of the frustule material. SAXSdata (resolution 3 to 65 nm) provided information ongeometry, size, and distribution of pores in the silica.

Overall, two pore regions were recognized that werecommon to the silica of all samples: the smallest (dless than 10 nm) regularly spaced and shaped spheri-cally, the larger (up to 65 nm) being cylinders or slits.Apparently, at a nanoscale level diatomaceous silica isquite homologous among species, in agreement withthe chemical principles of silica polymerization underthe conditions of pH and precursor concentrations in-side the silicon deposition vesicle. The final frustule“macro”-morphology is of course species-specific,being determined genetically. Synthetically-derivedMCM-type silicas have a similarly organized pore dis-tribution in an amorphous silica matrix as we foundin all diatom species studied. We therefore suggestthat organic molecules of a kind used as structure-direct-ing agents to produce these artificial silicas play a rolein the nucleation of the silica polymerization reactionand the shaping of pore morphology inside the sili-con deposition vesicle of diatoms. Structure-directingmolecules now await isolation from the SDV, followedby identification and characterisation by moleculartechniques.

208A REASSESSMENT OF ITS/5.8S DNA SE-QUENCE VARIATION AND PHYLOGENETICSIGNAL IN THE SYNUROPHYCEAEWee, J. L.Department of Biological Sciences, Loyola University,New Orleans, LA 70118 USA

Previously, DNA sequences were determined for theentire ITS/5.8S region by direct sequencing of PCRamplification products. 28 sequences were obtainedfrom 12 species of Synurophyceae, including Tessellariavolvocina, Chrysodidymus synuroideus, six species of Syn-ura and four species of Mallomonas. Sequences alsowere determined from multiple strains of some spe-cies, including 15 strains of Synura petersenii. Thelength of these sequences varied from 495–598 bp.The large amount of ITS/5.8S length variation madeinitial attempts in determining reliable sequencealignment difficult and precluded their use in phylo-genetic analyses of the class. Subsequently, the ap-proach of Bogler & Simpson (1996) was investigatedwhere reiterative, computer assisted alignments weregenerated and the quality of the alignment was evalu-ated ‚y homoplasy index and consistency index val-ues. However, these alignments also were equivocal.ITS/5.8S sequences sorted the 15 S. petersenii strainsinto two well supported ITS lineages. One ITS type in-cluded ten isolates from North America while isolatesfrom the second ITS type included one each fromGermany and Australia and three from North Amer-ica. Results are presented here where the sequencesfrom the 15 S. petersenii isolates were used to charac-terize ITS-1 and ITS-2 RNA transcript secondary struc-ture. Next, this information was expanded to includeITS/5.8S sequences from the other taxa in the class.

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Finally, the characteristics of ITS 1 and ITS 2 RNAtranscript secondary structure were used as a guide toalign all of the ITS/5.8S sequences from the Synuro-phyceae in a final phylogenetic analysis.

209BIOGEOGRAPHY OF ASEXUAL AND SEXUALREPRODUCTION IN CALOGLOSSA (DELES-SERIACEAE, RHODOPHYTA) FROM AUS-TRALIA AND NEW ZEALANDWest, J.1, M. Kamiya2 & G. Zuccarello3

The School of Botany, University of Melbourne,Parkville Victoria 3052, Australia; 2Kobe UniversityCenter for Inland Seas, Iwaya, Awaji-cho, 656-2401Japan; 3School of Biological Sciences, University of NewSouth Wales, Sydney 2052, Australia

Caloglossa species are widely distributed in mangrovesand salt marshes around the world and their life historypatterns are being investigated in laboratory culture.In Australia all isolates of C. monosticha, C. postiae andC. ogasawaraensis have Polysiphonia-type (P-type) sexuallife histories. Among the 70 C. leprieurii isolates fromAustralia and New Zealand P-type sexual reproduc-tion also is dominant. However, ten isolates of C. lep-rieurii from the Spencer Gulf and the Gulf of St. Vincentin South Australia give rise to successive tetraspor-phyte generations without gametophytes. Moreover,one isolate from Queensland is asexual. Only one SouthAustralia isolate, obtained from Lake Alexandrina atthe mouth of the Murray River, is sexual. South Austra-lia and Pacific Mexico are two regions in which asex-ual reproduction is dominant. In another mangrovedwelling red alga Bostrychia moritiziana (Rhodomelaceae)non-sexual reproduction also is frequent in Australia,New Caledonia and Bali (Indonesia). This asexual re-productive pattern of tetrasporophytic recycling ap-pears to have arisen independently among individualpopulations of various red algal species in differentregions. Investigations are underway on the molecularphylogeny of the Caloglossa leprieurii isolates.

210ANABAENA AND MICROCYSTIS IN THE PACIFICNORTHWEST: A TALE OF PLASTICITYWilliams, C. R., Peters, B. & Waaland, J. R.Department of Botany, Box 355325, University ofWashington, Seattle, WA 98195 USA

The molecular marker, cpcBA-IGS, was used to exam-ine the biogeography of representatives of Anabaenaand Microcystis collected from Pacific Northwest lakesand their phylogenetic relationship to isolates fromthe UTEX and CCAP culture collections. cpcBA-IGScontains portions of the alpha and beta subunit of cy-anophycocyanin with an intergenic spacer (IGS) ofz100 base pairs situated between the subunits. The

use of this cyanobacteria specific marker and primersallowed us to amplify cpcBA-IGS DNA from uni-cy-anobacterial field samples. The morphology andhabit of specimens were documented by photomicros-copy. Single filaments or colonies of field materialand 3–4 filaments of culture material were then am-plified using the polymerase chain reaction (PCR).Results include analysis of non-toxic summer andtoxic winter blooms of Anabaena from 1989–1997 inAmerican Lake, WA and a comparison of non-toxicand toxic Microcystis from Lake Sammamish, WA. Apreliminary phylogenetics analysis of Pacific North-west and UTEX isolates also was performed using par-simony, maximum likelihood and distance methods.The results of this analysis suggest that revision ofAnabaena and Microcystis taxonomy may be needed.

211MECHANISMS CONTROLLING NUCLEARMIGRATION ALONG THE TRICHOGYNE INTHE RED ALGA, BOSTRYCHIA MORITZIANA(RHODOMELACEAE, RHODOPHYTA)Wilson, S. M., Pickett-Heaps, J. D., & West, J. AThe School of Botany, University of Melbourne,Parkville 3010, Victoria AUSTRALIA

Sexual reproduction in red algae has been studied forover a century primarily for taxonomic purposes. De-spite this interest, only recently have the criticalevents of fertilisation been revealed. Time-lapse videomicroscopy techniques have been used to documentthe stages in the fertilization process within Bostrychiamoritziana. Once plasmogamy between a trichogyneand spermatium is achieved, two differentiated malenuclei may enter the trichogyne. One of the two mi-grates to the carpogonium while the other travels inthe opposite direction towards the trichogyne tip andplays no further role in fertilisation. The precisemechanism governing this bidirectional movement ofmale nuclei is unknown, but the cytoskeleton is be-lieved to be involved. Fluorescent staining and confo-cal microscopy shows an extensive arrangement of ac-tin filaments in spermatia and along trichogynes yetmicrotubules are only evident in dividing spermatia.Actin filaments appear to be involved in plasmogamyand ensheath male nuclei as they migrate from thespermatium and as they travel along the trichogynein either direction. Drug-inhibition studies and UV-microbeam irradiation indicate nuclear migrationalong trichogynes is actin/myosin dependent

212MITOSIS, CELL WALL AND FLAGELLA SYN-THESIS IN SYNCHRONIZED CULTURES OFTHE PRASINOPHYTE, SCHERFFELIA DUBIAWustman, B. A., Becker, B., & Melkonian, M.Botanical Institute, University of Cologne, 50931 Co-logne, Germany

72 PSA ABSTRACTS

Cell division occurs within the parental cell wall, yield-ing two progeny cells. Since Scherffelia dubia sheds allfour flagella prior to cell division, the maturing prog-eny cells must regenerate new cell walls and flagelladuring and/or after cytokinesis. To better understandthese processes, we have synchronized cell division incultures of S. dubia and observed all stages of mitosis,cytokinesis, and progeny cell maturation, includingflagella and cell wall formation, via DAPI staining offixed cells, DIC microscopy of live cells embedded inagarose and standard TEM. Microscopical observa-tions revealed the following sequence of events: 1)Golgi stacks divide during late interphase and imme-diately begin producing theca scales; 2) deflagellationand release of the parental cell wall from the plasmamembrane occurs during early prophase; 3) synthesisof theca and flagella scales within the Golgi and/orscale reticulum continues throughout mitosis; 4) dur-ing cytokinesis, a coalescence of vesicles containingtheca scales at the posterior end of the cell results in acleavage furrow slightly diagonal to the cells’ longitu-dinal axis (40 min); 5) post-mitotic nascent basal bodyformation and flagella elongation at the inheritedbasal bodies (and later at the mature nascent basalbodies) occurs concurrently with continued cell wallsynthesis; 6) the cleavage furrow rotates into a trans-verse position (35 min); 7) reorientation of the nucleiresults in a “head to tail” orientation of the maturingprogeny cells; and 8) matured progeny cells emergefrom the posterior end of the parental theca not be-fore 8 hrs after the onset of mitosis.

213MARINE MACROALGAL DIVERSITY IN THEREPUBLIC OF PANAMAWysor, B.1, Kooistra, W. H. C. F.2, Fredericq, S.11The University of Louisiana at Lafayette, Departmentof Biology, PO Box 42451, Lafayette, LA 70504 USA;2Mariene Biologie, Biologisch Centrum Postbus 14,9750 AA Haren (GN), The Netherlands

The marine flora of Panama remains poorly de-scribed to date, having been described from a few spo-radic and species poor (,50 species) collections inthe early half of the century and a couple of dedicatedsurveys in the latter half. With the exception of a fewstudies that have focused on particular genera or spe-cies, only a single marine floral survey has been pub-lished in the past three decades. In 1999 we collectedmarine algae from nearly 100 different collection sitesalong both coasts of Panama over a 10 month periodof time. Over 1500 specimens have been curated, rep-resenting 250 Caribbean species and 117 Pacific spe-cies. This is an increase in algal diversity of approxi-mately 100 and 50% for the Caribbean and Pacificflora, respectively, relative to Earle’s compilation of1972. We estimate that algal diversity in Panama mayapproach 450 species as the remaining 30% of the col-

lection is identified and previous records are incorpo-rated. Aspects of biogeography will be discussed inlight of such extraordinary diversity over a relativelyconfined region.

214IN SITU GROWTH AND REPRODUCTION OFPORPHYRA PERFORATA IN THE PACIFICCOAST OF BAJA CALIFORNIAZertuche-Gonzalez, J. A.1, Pacheco-Ruiz, I.1, Cabello-Pasini, A.1, Chee-Barragan, A.1, Guzman, J. M.1Galvez, A.1 & Arroyo, E.1, Yarish, C.21Instituto de Investigaciones Oceanologicas, Univer-sidad Autonoma de Baja California. PO Box 453,Ensenada, 22860 Mexico; 2University of Connecticut,One University Place, Stamford, CT 06901-2315,USA

Porphyra perforata is a common species off the Pacificcoast of Baja California peninsula. In situ growth, phe-nology and reproductive characteristic of this plantare being determined in order to evaluate the feasibil-ity of its culture in open water conditions. Contrary toprevious studies that describe this species as ephym-eral, P. perforata is present all year around off thenorth coast of the Baja California peninsula. Its verti-cal distribution is limited to a band, 150 to 1150 cmabove sea level. However, subtidal growth transplantexperiments showed that the plants are capable ofgrowing down to a depth of 5 m. Highest growth rateswere observed from February to July, then tissue waslost as a consequence of sexual reproduction. Biomasscontinues to decreases for the rest of the year. About50% of the plants were reproductive by May and morethan 90% by August. Oysters shells were introducedand collected every month to evaluate the presence ofchonchocelis phase and P. perforata recruitment.Chonchocelis was observed all year and new recruitswere present from September to February. These re-sults suggest that the foliar phase P. perforata could becultured in the ocean for about six months of the yearand could be culture subtidally.

215CONFIRMATION OF CATFISH MORTALI-TIES RESULTING FROM MICROCYSTIN PRO-DUCED DURING MICROCYSTIS BLOOMSZimba, P. V.1, Khoo, L.1, Carmichael, W. W.2, &Gaunt, P.11Thad Cochran National Warmwater Research Center,U. S. Department of Agriculture, Agricultural ResearchService, Stoneville, MS 38776 USA; 2Department of Bi-ological Sciences, University of Dayton, Dayton, OH05435 USA

Enigmatic deaths of finfish have occurred in freshwa-ter systems for many years. Some of these fish mortali-

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ties can be attributed to the accumulation of cyano-bacterial toxins during ingestion of floating feeds orpassively through opercular ventilation. We recentlywere able to document the accumulation of microcys-tin and resulting catastrophic mortality of pond-raisedcatfish (Ictalurus punctatus). The causative organism,Microcystis aeruginosa, was the dominant phytoplank-ton component within the cooler fall-winter season.Microcystin, a hepatotoxin produced by Microcystis,was detected in water and catfish liver samples. Fishexposed to pond water containing this bloom werekilled within 24 h. Necropsy of fish exposed to pondwater revealed congested liver and spleen tissues. En-vironmental conditions associated with several similarbloom events suggest several predictive options toforecast conditions supporting toxin formation, par-ticularly temperature.

216MICROSCOPIC INVESTIGATIONS OF STROM-BOMONAS WITH SPECIAL REFERENCE TORELEASE FROM THE LORICA FOLLOWINGCELL DIVISIONZimmermann, S.1, Conforti, V.2 & Triemer, R. E.11Division of Life Sciences, Rutgers University, Piscat-away, NJ, 08854 USA; 2Departmento de Biología, Fac.Cs. Exactas y Naturales, Ciudad Universitaria, Pab.II, 1428, Buenos Aires, Argentina

The Euglenophyta include four genera of Euglena-likecells enclosed in a lorica. Two of these genera, Trache-lomonas and Strombomonas, are free swimming. Thesetaxa have been differentiated and classified at the ge-neric and species level based primarily on the mor-phology of their lorica. Numerous SEM studies havebeen conducted, yet few, if any, TEM descriptions ex-ist, especially for Strombomonas. This study describesboth the outer lorica and internal ultrastructure forStrombomonas sp. isolated from a fresh water pond inNew Jersey. Additionally, we describe the release ofdaughter cells from the lorica following cell division.Two cells were observed within a single Strombomonaslorica following cytokinesis. When exposed to thelight of the microscope, one or both of the cells

emerged through the neck of the lorica. The releasedcells could easily be mistaken for Euglena species.

217FIVE CRYPTIC SPECIES OF PORPHYRA FROMTHE NORTHWEST ATLANTICNeefus, C. D.1, Mathieson, A. C.1, Yarish, C.2,Klein, A.3, West, A.3, Teasdale, B.1 & Hehre, E. J.11Department of Plant Biology, University of NewHampshire, Durham NH 03824 USA; 2Department ofEcology and Evolutionary Biology, University of Con-necticut, Stamford, CT 06901 USA; 3Department ofBiochemistry, University of New Hampshire, Durham,NH 03824 USA

As one part of a multi-institutional project on the biol-ogy of Porphyra, we collected extensive populationsamples of native Porphyra species from Long IslandSound to Nova Scotia. Samples were initially identi-fied to species based on morphological features usingtaxonomic keys in Bird & McLaughlin (1992). Collec-tions were analyzed using starch gel electrophoresis tolook for intra-specific variation useful in assessingpopulation genetics. Isozyme variation in samples thathad been originally identified as Porphyra leucostictawas far greater than expected. Samples from somecollections differed by as much as 7 out of 7 loci.Other investigators have used starch gel electrophore-sis to reveal cryptic differences in Porphyra that led tothe descriptions of new species. In light of ourisozyme results, we began a thorough examination ofwhat had been identified as P. leucosticta in the north-western Atlantic. The study included new collectionsas well as herbarium specimens. We examined mor-phology, habitat, seasonality, reproductive patterns,cell size & shape. We also extracted DNA and se-quenced 1484bp of the rbcL gene. Based on this evi-dence, we feel we can circumscribe at least five dis-tinct taxa of Porphyra not previously described fromthe northwestern Atlantic. Whether these representnew species, or previously described taxa from othergeographic regions, we are not yet certain. Wepresent here in detail, descriptions of each speciesalong with summarized results of isozyme and DNAanalyses.