Upload
dangdiep
View
226
Download
0
Embed Size (px)
Citation preview
Division Haptophyta = “Svepeflagellater”
Emiliania huxleyiPhoto: E. Paasche
ca 280 species and 75 genera
content
ecological significanceprincipal characteristics morphology and ultrastructurephylogenynutritiontaxonomycoccolith formationlife cyclesome members
Haptophyta - some members
Phaeocystis
Pleurochrysis
PrymnesiumCanter-Lund & Lund
Chrysotila
Hibberd
EmilianiaPaasche
Eikrem
Chrysochromulina
CalcidiscusCros & Fortuños
Ecological significance of Haptophyta
Descloitres, MODIS Rapid Response Team, NASA/GSFCTurner, Brazos River Authority
Paasche
Prymnesium parvum in Texas
Emiliania huxleyi / coccolithophorids
Dover cliffsOslofjord
Iceland
Effect on climate
Emiliania huxleyi, a cosmopolite, form blooms that influence global climate
DMSP = dimethylsulfoniopropionateDMS= dimethylsulfideacrylic acid
distribution and ecological significans
most are marine, present in all seas
mostly nanoplanktonic (2-20 µm)
important primary producers
highest diversity in tropical-subtropical open ocean
some may form extensive blooms
coccolithophorids influence biogeochemical processes
chalk (kritt) produced by coccolithophorids
Based on several genes and ultrastructure---- Lines suggested from environmental PCR Baldauf 2003. Science 300: 1703-6
Tree of Eukaryota
Chromalveolate hypothesis Cavalier-Smith
plastid in chromalveolates from a single endosymbioticevent
-> both host lineages and plastids share a common ancestor
Cavalier-Smith 2004. In: Hirt & Horner (eds).
Chromalveolate hypothesis
Harper et al. 2005: J. Syst. Evol. Microbiol. 55:487-496
analysis of six nuclear-encoded genes for cytoplasmic proteins in all major lineagesstrongly support heterokonts + alveolatesweakly support haptophytes + cryptophyteschromalveolates paraphyletic
number of coccolithophorid species over time
coccolithophorids in fossil records from ca 300-250 mill. years
(Carbon-Perm), but Haptophyta is probably > 600 mill. years
Several mass extinctions
Classification~75 genera, ~280 speciesUntil 1962 included in Chrysophyceae, ChromophytaHaptophyceae Christensen 1962 Prymnesiophyceae Hibberd 1976Haptophyta Hibberd ex. Edvardsen et Eikrem 2000Pavlovophyceae (Cavalier-Smith) Green et Medlin2000Prymnesiophyceae: 4 orders, Edvardsen et al. 2000Prymnesiophyceae: 6 orders, Jordan et al. 2004Prymnesiophyceae renamed to Coccolithophyceae, Silva et al. 2007.
General featuresTwo similar flagella with no tubular hairsHaptonemathe haptonema can coil or bend, but not beatit may adhere to substratum and be used in food handlingCells covered by organic scales Calcified scales (coccoliths) may be present
chloroplast
haptonema
flagella
scales
Throndsen
Ultrastructure
1-4, usually 2 chloroplasts4 plastid membranesthree thylacoids in lamellano girdle lamellachloroplast usually with pyrenoidGolgi (dictyosome) close to basal bodiesflagellar apparatus - a phylogenetic marker
Inouye 1997. Algae 12:247-61
Eikrem & Edvardsen 1999.Phycologia 38:149-55
Ultrastructure2 flagellahaptonema (H, 6-7 microtubuli)Golgi-apparatus (G)PER2-4 plastids3 lamella (L)chrysolaminaran (CHR)organic scales (SC)mucilage bodies (MB)4 membranes, 2ER+2CE Chrysochromulina
chloroplasts, pigments and storage productgolden or yellow-brown chloroplasts with 4 membranestriple thylakoidsno girdle lamellapyrenoidPigments: kl. a, c1 og c2, c3,fucoxanthin, b-carotene, diatoxanthin, diadinoxanthin, 19’hexanoyloxyfucoxanthin,19’butanoyloxyfucoxanthinstorage product:chrysolaminaran
Function of haptonema “heftetråd”
to attachto handle food (in some Chrysochromulina)to avoid collisions
Food uptake
Prymnesiumcan ingestalgae and bacteria by phagotrophy
Toxin(s) paralyse and kill the prey
Prymnesium ingesting a green alga (Tillmann 1998)
Organic scalesEllipsoid organic scales with microfibrillarpattern
scales are species specific, but different life cycle stages may have different scale pattern
Scale pattern evident in TEM A Light micrograph of P. parvum
B Electron micrograph of scales
Photos: W. Eikrem
Ultrastructure of coccolithophorid
coccoliths
vesicles from Golgi with coccolith
coccoid
Emiliania huxleyi
Holococcoliths
Calyptrolithophorawith holococcoliths
holococcoliths consist of small, equally sized crystals
are formed extracellularly
Haplo-diploid heteromorphic lifecycle in Pleurochrysis carterae
Apistonema-stage, n
spores, 2n
Hymenomonas- stage, 2nmeiose
syngami
zooids, n
gamet, nzygot, 2n
Alternating heterococcolithophorid-holococcolithophorid life cycles
Knappertsbusch nhm
Coccolithus pelagicus Coccolithus pelagicus ssp. pelagicus HOL(= Crystallolithus hyalinus )
All holococcolithophorids are expected to be the haploid stage in the life cycle of a diploid heterococcolithophorid
nhm
Haptophyte phylogeny SSU rDNA
OLI16010OLI51080
OLI51076Crypthecodinium
OLI26047
Phaeocystis sp. 1
Phaeocystis antarcticaPhaeocystis pouchetii
Phaeocystis globosa
Phaeocystis sp. 2
OLI51004
Pavlova gyrans
Pavlova CCMP 1394Pavlova CCMP1416
Pavlova aff. salina
Fucus
}CLADE D
100/100
100/100
100/100
100/100
100/100
99/100
99/ 100
96/75
OLI51050OLI26041
Isochrysis galbanaPleurochrysis carteraeCCMP 300
Coccolithus pelagicusReticulosphaera japonensis
Emiliania huxleyi/Gephyrocapsa oceanicaCCMP 625
Pleurochrysis sp. CCMP 875Pleurochrysis elongata
Cruciplacolithus neohelis100/100
100/100
100/100
100/100
100/100
98/98
99/99
99/9993/74
65/89
87/57
76/6560/60
OLI16029
OLI16108OLI26017OLI51102
Chrysochromulina throndseniiChrysochromulina acantha
Chrysochromulina campanulifera
Chrysochromulina polylepisChrysochromulina kappa
Imantonia rotundaPrymnesium nemamethecum
Chrysochromulina hirta
Prymnesium calathiferumPrymnesium parvumPrymnesium patelliferum
OLI51059OLI51033, OLI51056
100/100
100/100
100/100
66/9879/98
79/8958/89 76/57
73/99
75/86
Chrysochromulina scutellum
99/67
97/100
98/97
100/100
2%
}CLADE E
-/60
66/-
Edvardsen et al. 2000. Phycologia 39:19-35.
ML-analysis
6 % divergence
Pavlovophyceae
Prymnesiophyceae
Prymnesiophyceae(=Coccolithophyceae)
Two smooth, more or less equal flagella inserted apicallyNo eyespot Cells usually covered by organic plate scales Mineralized scales (coccoliths) or spine scales may be present Haptonema may be conspicuous
Throndsen
Prymnesiophycean phylogeny SSU rDNA
OLI16010OLI51080
OLI51076Crypthecodinium
OLI26047
Phaeocystis sp. 1
Phaeocystis antarcticaPhaeocystis pouchetii
Phaeocystis globosa
Phaeocystis sp. 2
OLI51004
Pavlova gyrans
Pavlova CCMP 1394Pavlova CCMP1416
Pavlova aff. salina
Fucus
}CLADE A
CLADE C
}CLADE D
100/100
100/100
100/100
100/100
100/100
99/100
99/ 100
96/75
OLI51050OLI26041
Isochrysis galbanaPleurochrysis carteraeCCMP 300
Coccolithus pelagicus
Emiliania huxleyi/Gephyrocapsa oceanicaCCMP 625
Pleurochrysis sp. CCMP 875Pleurochrysis elongata
Cruciplacolithus neohelis
}100/100
100/100
100/100
100/100
100/100
98/98
99/99
99/9993/74
65/89
87/57
76/6560/60
OLI16029
OLI16108OLI26017OLI51102
Chrysochromulina throndseniiChrysochromulina acantha
Chrysochromulina campanulifera
Chrysochromulina polylepisChrysochromulina kappa
Imantonia rotundaPrymnesium nemamethecum
Chrysochromulina hirta
Prymnesium calathiferumPrymnesium parvumPrymnesium patelliferum
OLI51059OLI51033, OLI51056
}CLADE B1
}CLADE B2
100/100
100/100
100/100
66/9879/98
79/8958/89 76/57
73/99
75/86
Chrysochromulina scutellum
99/67
97/100
98/97
100/100
2%
}CLADE E
-/60
66/-
Based on Edvardsen et al. 2000. Phycologia 39:19-35.
ML-analysis
Reticulosphaera japonensis
Phaeocystales
Prymnesiales
Coccolithales
Isochrysidales
A. Phaeocystales
Swimming cells with two equalflagella and small plate scales
Short, stiff haptonema
Some produce filamentousstarlike structures
Some have a complex lifecycle that include a colonialstage with cells in a gelatinousmatrix
Phaeocystis pouchetii
Phaeocystis globosa
Zingone
Phaeocystis cordata
star of fibrils
Phaeocystis spp. life cycle
colony
Five stages are proposed for P. globosa:
1. Non-flagellated solitary cell, 2n
2. Non-flagllated cell in colony, 2n
3. Macroflagellates, 2n
4. Mesoflagellates, n
5. Microflagellates, n