Journal of Foraminiferal Research, v. 32, no. 3, p. 252–273, July 2002

BENTHIC FORAMINIFERAL ASSEMBLAGES FROM THE SOUTHERN KARA SEA,A RIVER-INFLUENCED ARCTIC MARINE ENVIRONMENT

LEONID POLYAK1*, SERGEI KORSUN2, LAWRENCE A. FEBO1, VLADIMIR STANOVOY3, TATYANA KHUSID2,MORTEN HALD4, BJORN EGIL PAULSEN4, AND DAVID J. LUBINSKI5

ABSTRACT

Calcareous foraminifers and hydrographic parameters in 113bottom samples from the southern Kara Sea were examined toimprove the usage of foraminifers as paleoenvironmental proxiesfor river-dominated high-latitude continental shelves. Foraminif-eral taxa form a succession from near-estuarine to distal open-sealocations, characterized by a gradual increase in salinities. Fora-miniferal assemblages are discriminated into three groups: river-proximal, -intermediate, and -distal. This succession appears to becontrolled by a combination of feeding conditions and bottom sa-linities, and are related to riverine fluxes of freshwater, organicmatter, and sediments. Morphological and behavioral adaptationsof foraminifers to specific environments are discussed.

INTRODUCTION

Arctic riverine inputs play a critical role not only in highlatitude hydrographic and biological systems, but also in theclimatic system through controls on sea-ice coverage and inter-oceanic water mass exchange (e.g., Aagard and Carmack, 1994;Driscoll and Haug, 1998; Stein, 1998; Forman and others,2000). Arctic runoff has an especially profound influence onhydrography, sedimentation, and biology on the continentalshelves adjacent to river mouths. From these areas, riverinewater spreads throughout the Arctic Ocean, where it controlsthe vertical structure of the upper water column and sea-iceformation. River water also supports biological productivity bydelivering nutrients (e.g., Jones and others, 1990; Rudels andothers, 1991). Low-salinity surface waters exported from theArctic Ocean affect overturning in the Nordic and Labradorseas, and thus the formation of North Atlantic Deep Water,which ventilates the World Ocean (e.g., Aagard and Carmack,1994). During glacial periods, the Arctic hydrographic envi-ronments expanded southwards and dominated even larger ar-eas than at present. Because of the potential increase in high-latitude precipitation with atmospheric warming, the future de-velopment of the Arctic hydrology may have significant effectsboth on oceanic circulation and climate (Cattle and Crossley,1995; Delworth and others, 1997). More studies are requiredto better predict this future development, including new pa-leoenvironmental investigations that yield improved insightinto past climate variability and the evolution of the arctic cli-mate system.

Benthic foraminifera are a valuable but poorly understoodpaleobiological proxy for the reconstruction of environmentalconditions on continental shelves occupied by Arctic waters.Benthic foraminifera have a wide environmental distributionand high preservation potential. They occur in many environ-ments ranging from glaciated fjords and river estuaries to deep

1 Byrd Polar Research Center, Ohio State University, Columbus,Ohio 43210, USA.

2 P. P. Shirshov Institute of Oceanology, Moscow 117851, Russia.3 Arctic and Antarctic Research Institute, St. Petersburg 199397,

Russia.4 Institute of Geology, University of Tromsø, N-9037, Norway.5 Institute of Arctic and Alpine Research, University of Colorado,

Boulder, CO 80309, USA.* Corresponding author: Byrd Polar Research Center, 1090 Carmack

Rd., Columbus, OH, 43210; tel. 614-292-2602, fax 614-292-4697,E-mail: polyak.1@osu.edu

oceanic basins (e.g., Todd and Low, 1966, 1980; Mudie andothers, 1983; Wollenburg and Mackensen, 1998a). However,patterns of foraminiferal distribution in the Arctic and relatedenvironmental controls are still poorly understood. This paperanalyzes assemblages of benthic calcareous foraminifers in thesouthern Kara Sea, an area characterized by a uniquely strongeffect of riverine waters (Figs. 1–2). Our results provide a bet-ter understanding of the modern patterns of foraminiferal dis-tribution, which can be applied to the Quaternary subfossil re-cord to help interpret the evolution of Arctic marine environ-ments affected by riverine inputs.

GEOGRAPHIC SETTING

The study area is located north of the western Siberian Low-land and is separated from the Barents Sea to the west by theNovaya Zemlya islands (Fig. 1). Physiographically, the south-ern Kara Sea can be divided into two main areas: a shallow(mostly ,50 m) eastern area adjacent to the estuaries of theOb and Yenisey rivers and a western area with water depthstypically exceeding 100 m and reaching .500 m in the narrowNovaya Zemlya Trough (Fig. 2).

Runoff to the Kara Sea is controlled by the Ob and Yeniseyrivers, which drain a huge catchment area extending to thenorthern slopes of the Tibetan Plateau (Fig. 1). The mean an-nual discharges of the Ob and Yenisey are approximately 400and 580 km3, respectively; their combined discharge is almosttwo times that of the Mississippi River and constitutes morethan ⅓ of the total runoff into the Arctic Ocean (R-ArcticNET,2001). More than 75% of this discharge occurs between Mayand September, the spring-summer flooding period. The off-shore spreading of riverine waters, incorporated in the generalKara Sea water circulation, varies depending on winds andcommonly affects almost half of the total sea area; the multi-annual pattern is characterized by net eastward transport intothe Laptev Sea (Figs. 2–3; Burenkov and Vasil’kov, 1995; Pav-lov and others, 1996). In the shallow area north of the Ob andYenisey estuaries, riverine inputs strongly affect the bottom wa-ter (Fig. 4). In the deeper area further west, a pycnocline per-sists through summer at ca. 20–30 m, separating surface andmore saline bottom waters. The deep Novaya Zemlya Troughcontains dense, fully saline water that is probably produced bybrines during sea-ice formation. The overall modern hydro-graphic pattern in the southern Kara Sea is characterized by asteady increase and stabilization of salinities with distance fromthe estuaries. Surface water salinities range from ,5 psu (prac-tical salinity units) in the estuaries to 30 psu in distant areas;corresponding bottom salinities range from ,30 to .34.5 psu(Figs. 3–4). The strongest salinity gradients (fronts) are locatedimmediately north of the estuaries; an additional sharp gradientin bottom salinity occurs at the bathymetrically controlledboundary between the shallow eastern area and the deeperwestern area. The bottom temperature pattern (Fig. 5) hasweaker gradients and is more complex than that of salinitybecause of multiple factors such as insolation, the timing of icebreak-up, and the formation and distribution of brines. Gener-ally, bottom temperatures in the Kara Sea do not exceed 08Cexcept for shallow sites in the proximity of the estuaries andin Baidarata Bay (Pavlov and others, 1996).

253BENTHIC FORAMINIFERAL ASSEMBLAGES FROM THE SOUTHERN KARA SEA

FIGURE 1. Circum-arctic map showing rivers discharging to Arcticseas (line thickness of rivers represents relative runoff) and the catch-ment for the Kara Sea (dotted line). Base map courtesy of R. Lammers,University of New Hampshire.

FIGURE 3. Summer surface salinity in the Kara Sea, multi-yearmeans. Shading highlights salinities .20 psu.

FIGURE 2. Map of the Kara Sea showing bathymetry (25, 50 100,200, 300, and 400 mwd contour lines) and a generalized surface currentsystem. Shadings highlight depths .50 m and .200 m.

FIGURE 4. Summer bottom salinity in the Kara Sea, multi-yearmeans. Shading highlights salinities .34 psu.

The Ob and Yenisey discharge largely controls not only thehydrographic structure, but also the sedimentation and biolog-ical productivity in the southern Kara Sea. The combined an-nual runoff delivers .22 3 106 tons of suspended matter andalmost 8 3 106 tons of organic matter, particulate and dissolved(Gordeev and others, 1996). The bulk of suspended load isdeposited in front of the estuaries, at the mixing zone betweenpredominantly riverine and marine waters (Lisitzin and others,1995, 2000). This depositional regime is marked by seafloorareas of fine-grained sediment off estuary mouths, contrasting

with generally coarse sediment in the shallow part of the sea(Fig. 6). Beyond the surface isohaline of 20 psu (cf. Fig. 3),concentrations of suspended load drop to values two orders ofmagnitude lower than in the estuaries (Lisitzin and others,2000). The remaining fines are distributed by currents through-out the shelf and are partly exported into the Arctic Ocean bysurficial waters and/or ice.

Biological productivity in the Kara Sea has not been moni-tored as extensively as hydrography, but data from several sum-mer seasons provide a general characterization of productivity-related processes (e.g., Vedernikov and others, 1995; Nothigand Kattner, 1999). As runoff contains large amounts of nutri-

254 POLYAK, KORSUN, FEBO, STANOVOY, KHUSID, HALD, PAULSEN, AND LUBINSKI

FIGURE 5. Summer bottom temperature in the Kara Sea, multi-yearmeans (8C). Shading highlights temperatures ,218C.

FIGURE 6. Sand (.63 mm, %) in surficial bottom sediments in theKara Sea. Shadings highlight sand contents .25% and .50%. Crossmarks show data points. Russian data were approximately convertedfrom a metric grain-size scale to .63mm class by interpolating be-tween the .50mm and .100mm values on a logarythmic scale.

FIGURE 7. Summer bottom oxygen concentration in the Kara Sea,multi-year means (ml/l). Shading highlights concentrations ,7 ml/l.

ents and labile organic matter, productivity is generally high inand near the estuaries, reaching .300 mg C m22 day21, anddecreases to very low levels of ,50 mg C m22 day21 in theopen sea (Vedernikov and others, 1995). This pattern is en-hanced by a relatively early ice break-up in the estuaries andadjacent areas (Harms, 1997; Borodachev, 1998). The distri-bution of river-derived nutrients can be illustrated by concen-trations of silica in surface waters, which decrease ten-foldfrom the estuaries to the northern and western areas of the KaraSea (Rusanov and Vasil’ev, 1976; Makkaveev and Stunzhas,1995). However, excessively high suspended loads in runoffmay decrease biological productivity in the estuaries, causingmaximum production at some distance away (Vedernikov andothers, 1995). Apart from riverine influence, primary produc-tion blooms on the Arctic shelves are mostly connected withthe ice-melting zones, which may be the case for river-distalareas in the Kara Sea. The complex pattern of productivityblooms is illustrated by different groups of diatoms and dino-flagellates dominating the phytoplankton in various parts of theKara Sea in summer (Matishov, 1995; Vavilova and others,1998). Enhanced productivity has been observed near thecoasts of Novaya Zemlya, which may be related to the summermelting of glaciers (Matishov and others, 1989; Matishov,1995).

There are no comprehensive data on the fluxes of organiccarbon to the sea floor, but the total benthic biomass has highestvalues of .150 g m22 near the estuaries and decreases northand westwards, consistent with the general distribution patternof the primary productivity (Zenkevich, 1960; Matishov andothers, 1989). Extremely low benthic biomass of ,3 g m22

characterizes the deep Novaya Zemlya Trough, whereas theshallow area adjacent to Novaya Zemlya has elevated valuesof .25 g m22. It must be noted that total organic matter inbottom sediments may not be representative of food fluxes forbenthic communities because of a large contribution of old,refractory organics delivered by rivers (Stein, 1996; Boucseinand others, 1999).

Relatively high rates of production and sedimentation of or-ganic matter are exemplified by seasonally reduced levels ofbottom-water oxygenation off the estuaries (Fig. 7); however,

anoxic conditions have never been observed in the water col-umn. Because of decreasing biological production and sedi-ment fluxes, the oxidation of bottom sediments in river-distalareas is generally stronger, as evidenced by a thicker oxidizedsurficial layer reaching .20 cm as opposed to ,5 cm at theestuary mouths (Galimov and others, 1996).

MATERIALS AND METHODS

Our data set of modern benthic foraminifers combines pub-lished and new data from a total of 113 surficial sediment sam-

255BENTHIC FORAMINIFERAL ASSEMBLAGES FROM THE SOUTHERN KARA SEA

TABLE 1. Sources for the foraminiferal data set from surficial sediments of the southern Kara Sea (Fig. 8).

Author Ship/Year No. of samples Collection technique Publication

T. Khusid Dmitri Mendeleev, 1993;Professor Shtokman, 1992

31 (2 empty) Grab, boxcore,gravity core

Khusid & Korsun, 1996 1This study

L. Polyak Akademik Karpinski, 1991 25 (1 empty) Grab (stained) This studyB.-E. Paulsen Ivan Petrov, 1993–1994 23 Grab (stained) Paulsen, 1997S. Korsun Boris Petrov, 1997 21 Multicorer (stained) Korsun, 1999 1 This studyT. Troitskaya Pavel Bashmakov, 1980 8 Grab This studyL. Polyak (recount) Northwind, 1965 4 Grab Todd & Low, 1980 (species

occurrence data only)V. Slobodin 1953–1958 4 Gravity core Basov & Slobodin, 1965

FIGURE 8. Index map of sediment samples used for foraminiferalstudies (see Table 1). Dotted and solid lines show depth contours of50 and 200 mwd, respectively (same in Figs. 9–29).

pling sites (Table 1, Fig. 8). These sites provide a generallydense and even coverage of the southern Kara Sea, boundedby 778N and 868E towards the open sea; sparse samples beyondthese limits were not included. This large study area containsa set of river-influenced Arctic shelf environments that gradefrom estuaries to normal marine settings. Multi-year hydro-graphic measurements from the study area allow a thoroughcharacterization of temperatures, salinities, and oxygen content.Most sediment samples in this study were collected by grabsamplers, boxcores, or multicorers, which provide a good re-covery of surficial sediments representing the most recent timeinterval. Over half of all samples have been stained by RoseBengal and nearly all of them were found to contain live (orat least cytoplasm-bearing) foraminifers and other benthic meio-fauna. Furthermore, samples in Korsun’s collection were stud-ied wet to ascertain the identification of live specimens (Kor-sun, 1999).

Present sedimentation in the southern Kara Sea is estimatedto range between approximately 0.2 to 1 mm/yr, with the ex-ception of shallow areas subjected to winnowing (Levitan andothers, 1996; Polyak and others, 2000); these rates indicate thatthe samples (uppermost 1–2 cm of sediment) generally spanthe last several decades. Historical observations suggest no sig-nificant long-term hydrographic changes in the Kara Sea andadjacent seas other than multi-year to decadal-scale fluctua-

tions, except perhaps for a still poorly understood anomalouswarming trend in the Eurasian Arctic that started in the 1990’s(e.g., Shpaikher and Fedorova, 1973; Pavlov and Stanovoy,1997). Therefore, the investigated foraminiferal assemblagescharacterize mean multi-decadal modern environments.

To assess the hydrographic parameters on a time scale cor-responding to the foraminiferal samples, we compiled seasonaldata on bottom temperatures, salinities, and oxygen concentra-tions, as well as summer surface salinities from the southernKara Sea for the last 10 (winter) to 20 (summer) years fromthe historical database of the AARI (Joint U.S.-Russian Atlasof the Arctic Ocean, 1997, 1998). Data were included onlywhen coverage for a particular year and season spanned a ma-jority of the field area. Scattered data from each year weregridded and then all yearly grids were averaged to form meanmultiyear fields. (Figs. 3–5, 7). These fields provide the firstsystematic characterization of multi-annual hydrographic en-vironments in the southern Kara Sea. The mean grid-point val-ues were interpolated to the foraminiferal sampling sites fordirect comparison with foraminiferal distributions. We havealso compiled and plotted the distribution of surficial sedimentsusing grain-size data associated with the foraminiferal samplesand prior results of Kordikov (1958; Fig. 6).

Foraminifers have been counted in the .0.1 mm size frac-tion in most samples; .0.125 mm size was used for Korsun’ssamples. Foraminiferal composition does not appear to differsignificantly between these similar sieve sizes, as illustrated bylack of discrepancies in species distribution patterns. To keepour results comparable with down-core data, we analyzed thespecies composition of only calcareous foraminiferal assem-blages. Agglutinated (arenaceous) foraminifers easily disinte-grate after death and thus result in variable and typically verylow downcore abundances of tests or test fragments, dependingon diagenetic processes in sediment and sample processingconditions (e.g., Brodniewicz, 1965; Schroder, 1988). Rareplanktonic foraminifers were counted separately. Benthic spe-cies percentages (frequencies) were calculated for samples con-taining at least 25 calcareous specimens (average sample size5 128). This, generally low cut-off level was chosen in orderto balance the number of analyzed sites (especially in forami-niferal-poor river-proximal areas) and the accuracy of speciesrepresentation. A sample size of 25 provides a 0.95 probabilityof recording a species that has a 10% frequency in the popu-lation (Dennison and Hay, 1967). We present the distributionof 17 species, or groups of related species, each having a fre-quency of 10% in at least one sample and a mean frequencyof 2% minimum; in most samples these taxa account togetherfor over 90% of the total calcareous assemblages.

FORAMINIFERAL DISTRIBUTION

ENVIRONMENTAL FACTORS

All analyzed mean bottom-water variables, except summertemperature, have strong linear correlations with each other and

256 POLYAK, KORSUN, FEBO, STANOVOY, KHUSID, HALD, PAULSEN, AND LUBINSKI

TABLE 2. Linear correlation coefficients for environmental variables (multi-annual means for hydrographic parameters). Shown are only thecorrelations confident at P . 0.95. Values confident with Bonferroni correction applied are shown in bold.

SSS SBS WBS SBT WBT O2 % Sand

Ln Water DepthSummer Surface Salinity (SSS)Summer Bottom Salinity (SBS)Winter Bottom Salinity (WBS)Summer Bottom Temperature (SBT)Winter Bottom Temperature (WBT)O2 concentration, ml/l

0.66 0.680.72

0.640.880.81

20.44—

20.62—

20.5420.8320.7620.92

—

0.370.790.430.63—

20.59

20.25——————

FIGURE 9. Distribution of benthic foraminiferal abundance, com-bined calcareous and agglutinated (per gram of dry sediment).

FIGURE 10. Percentage of calcareous foraminifers in total benthicforaminiferal numbers.

with the surface salinity, which reflects a generalized riverinesignal (Table 2; Figs. 3–5, 7). This pattern highlights that hy-drographic processes in the southern Kara Sea are largely con-trolled by runoff fluxes (cf. e.g., Pavlov and others, 1996). Anadditional control on bottom-water properties is provided bybathymetry. However, because depths also change with dis-tance from the Ob and Yenisey estuaries, there may be a biasin the correlations. Summer bottom temperatures have a patterndiffering from the other measured parameters due to more com-plex controls and weaker gradients.

Similar to the hydrographic situation, biological and sedi-mentation processes in the southern Kara Sea appear to bestrongly affected by riverine fluxes. This trend is exemplifiedby inverse relationships between surface salinity and factorssuch as primary production, chlorophyll a concentration (Ved-ernikov and others, 1995; Nothig and Kattner, 1999) and totalsediment load (Lisitzin and others, 2000). Bottom sediments,however, show no relationship to hydrographic factors, andonly a weak correlation with water depth, probably due to ad-ditional effects of bottom currents and seabed topography onsediment distribution (Table 2; Fig. 6).

ABUNDANCE PATTERNS

Benthic foraminiferal abundance depends on the interplaybetween three main factors: productivity, dilution by clasticsediments, and taphonomic loss. The distribution of foraminif-

eral abundance in the Kara Sea (Fig. 9) shows consistently lownumbers near the estuaries, which may be mainly controlledby a high sediment load. Additionally, observations of fora-minifers from these sites, including cytoplasm-bearing speci-mens, indicate a strong dissolution of calcareous tests, possiblyassociated with low alkalinity of bottom water, (cf. Makkaveevand Stunzhas, 1995). Reduced salinity likely sets the barrier forforaminiferal propagation up the estuaries, with the lowestmean salinity at which foraminifers have been found in the Oband Yenisey near 5 psu. However, these samples contain just afew non-stained foraminiferal tests, which may have been re-deposited from older strata outcropping along the river banks.If this is the case, then the salinity cut-off rate is closer to 10psu. Low foraminiferal abundance is also characteristic of theNovaya Zemlya Trough and adjacent areas to the east, probablydue to a combination of low productivity and dissolution/dis-aggregation of tests. Strong calcium carbonate dissolution inthis area is corroborated by the generally low percentage ofcalcareous foraminifers (Fig. 10), although this index may bebiased by variable rates of disaggregation of arenaceous tests.Planktonic foraminifers, largely represented by the cold-waterspecies Neogloboquadrina pachyderma (sinistral), occur most-ly near the southern and northern tips of Novaya Zemlya, likelyreflecting inflows from the Barents Sea (Fig. 11).

SPECIES DISTRIBUTION

The mapped distribution of nearly all of the abundant speciesshows an orderly succession of maximal frequencies, reflecting

257BENTHIC FORAMINIFERAL ASSEMBLAGES FROM THE SOUTHERN KARA SEA

FIGURE 11. Distribution of planktonic foraminifers (% in total cal-careous counts).

FIGURE 12. Average frequencies of foraminiferal species vs. meansummer surface salinities in discrete increments. Plates A, B, and Cillustrate river-proximal, -intermediate, and -distal species, respectively.

optimal conditions or ecological stress tolerance of speciesalong a gradient from river-proximal to river-distal locations.Riverine inputs affect benthic communities through changes indelivery of freshwater, food, and total sediment, all generallydecreasing on the Siberian shelf with distance from the estu-aries (Zenkevich, 1960; Vedernikov and others, 1995; Lisitzinand others, 2000). As quantitative data on sediment and organ-ic-matter fluxes to the Kara Sea floor are sparse, we approxi-mate the riverine signal by the surface salinity, which is linkedwith productivity, nutrients, and sediment fluxes in this region(Rusanov and Vasil’ev, 1976; Makkaveev and Stunzhas, 1995;Vedernikov and others, 1995; Nothig and Kattner, 1999; Lis-itzin and others, 2000). To help quantify the distribution offoraminifera along the river-proximity gradient, mean multi-annual summer surface salinity was compared to the meanmaximal percentages of the abundant benthic foraminiferal spe-cies. Nearly all species show systematic relationships (Fig. 12).These relationships, combined with the link between salinityand distance from rivers, allowed us to differentiate three majortypes of assemblages: river-proximal, -intermediate, and -distal,corresponding to surface salinities of ,15, 15–25, and .25psu, respectively.

Unaveraged species percentages were compared to meanmulti-annual environmental values of depth, salinity, tempera-ture, oxygen, and sediment grain size using linear and 2nd or-der polynomial functions. Results for both function types showthe strongest relationships with depth and salinity (see Table 3for an example of linear-based results). This result probablyreflects the pervasive inter-relationships between river prox-imity, depth, salinity, productivity, nutrients, and sediment flux-es in the study area. The general lack of strong correlationswith any of the individual environmental variables probablyreflects complex responses of benthic foraminifers to environ-mental factors, as observed for many biological groups (e.g.,Jongman and others, 1995).

River-proximal Species

Elphidium incertum (Pl. 1, Figs. 1–7) has maximal fre-quencies in and near the Yenisey estuary, where they nearly

constitute the entire assemblage in some samples, and sharplyfall within a distance of ;300 km (Fig. 13). A population atthe Yenisey estuary differs morphologically from a typical E.incertum, as described from many Arctic/subarctic regions, bythe expansion of tuberculation in the umbilical area (Pl. 1, Figs.5–7). Although the systematics of E. incertum have not beenfully worked out (see Faunal Reference List, Appendix 1),available distribution data show its consistent affinity to areasaffected by riverine fluxes in temperate and high latitudes ofEurope, Asia, and North America (Brodniewicz, 1965; Lutze,1965; Todd and Low, 1966; Fursenko and others, 1979; Culverand Buzas, 1980; Lukina, 1990).

Haynesina orbiculare (Pl. 2, Figs. 1–3) is easily recogniz-able and is another major indicator of river-proximal environ-ments. In contrast to E. incertum, H. orbiculare is equallyabundant in front of both the Ob and Yenisey estuaries and itsfrequency decreases gradually towards the river-distal areas(Fig. 14). Overall, H. orbiculare has higher frequenciesthroughout the study area than E. incertum and is one of themost abundant species. The geographic occurrence of H. or-biculare is generally similar to that of E. incertum (Brodnie-wicz, 1965; Leslie, 1965; Lutze, 1965; Todd and Low, 1966;Lukina, 1990), but H. orbiculare has a wider distribution andis not uncommon in cold waters with relatively stable marinesalinities (e.g., Loeblich and Tappan, 1953; Lukina, 1977).

Polymorphinidae. Foraminifers of this family in the KaraSea occur most frequently in a narrow zone adjacent to theestuaries (Fig. 15). Although occurring in modern assemblages

258 POLYAK, KORSUN, FEBO, STANOVOY, KHUSID, HALD, PAULSEN, AND LUBINSKI

TABLE 3. Linear correlation coefficients between foraminiferal species and environmental variables (multi-annual means for hydrographic param-eters). Shown are only the correlations confident at P . 0.95. Values confident with Bonferroni correction applied are shown in bold. Abbreviationsas in Table 2.

Ln depth SSS SBS WBS SBT WBT O2 Sand

E. clavatumC. reniformeH. orbiculareE. subarcticumE. incertum

0.3920.47

0.5220.46

20.24

20.340.35

20.38

0.3320.30

0.3020.57

20.330.33

20.350.37

20.27 0.53

0.2720.32

0.26

0.260.25

20.26

20.4320.34

0.29

E. bartlettiBuccella spp.I. norcrossiS. loeblichiN. labradoricum

0.600.300.37

0.470.250.31

0.320.240.25

20.300.380.380.28

0.2520.37 0.39 20.24

C. lobatulusM. barleeanusA. gallowayiE. groenlandica

0.240.27

20.33

0.350.270.25

20.39

0.27

20.25

0.300.24

20.42 0.37T. fluensMiliolidaePolymorphinidae 20.39 20.46 20.50 20.54 0.51

in low numbers, polymorphinids have been reported from awide range of environments including shallow-water and low-salinity settings (e.g., Todd and Low, 1966; Madsen and Knud-sen, 1994). Our data suggest that the polymorphinids can beused as an indicator of the riverine signal on the Arctic shelves.

Elphidiella groenlandica (5E. gorbunovi; Pl. 2, Fig. 8) isyet another elphidiid that shows a clear river-proximal distri-bution (Fig. 16). This ecological affinity has been supported bymany observations from Arctic shelves, showing restriction ofthis large foraminifer to river-adjacent regions (e.g., Cooper,1964; Todd and Low, 1966; Tamanova, 1971; Lukina, 1990).

Elphidium bartletti (Pl. 2, Figs. 4–5). This elphidiid joinsE. incertum, H. orbiculare, and E. groenlandica in preferringriver-affected habitats, but its highest occurrences are fartherfrom the Ob and Yenisey estuaries and form a narrow zoneextending into the southwestern part of the study area (Fig. 17).This distribution largely co-occurs with sandy, shallow sea-floor areas off the estuaries (Fig. 6).

Buccella spp. combines closely related, intergrading speciesof B. frigida, B. hannai arctica, and possibly B. tenerrima (Pl.2, Figs. 14–17). Although widely distributed throughout theentire southern Kara Sea, Buccella spp. shows a preferencetowards river-affected areas and is even recorded from the Obestuary (Fig. 18).

River-intermediate Species

Cassidulina reniforme (Pl. 2, Fig. 12) has its maximumfrequencies in the intermediate zone between river-proximaland river-distal areas and avoids approaching the estuaries (Fig.19). C. reniforme is one of the most common calcareous for-aminifers on the Arctic shelves, occurring from glaciated fjordsto bathyal depths (e.g., Lukina, 1977; Sejrup and Guilbault,1980; Mudie and others, 1983; Mackensen and others, 1985;Korsun and others, 1994; Hald and Korsun, 1997). This speciesseems to prefer cold-water areas (temperatures below ca. 28C)with seasonal sea-ice coverage and muddy sediments and istypically not found in decreased salinities (below ;30 psu).

Trifarina fluens (Pl. 2, Fig. 18) is not abundant in the KaraSea, but its occurrences seem to show a preference to areasintermediately distanced from the estuaries (Fig. 20). In theBarents Sea and on the Iceland shelf, T. fluens has maximalabundances at relatively shallow water depths in the vicinityof the Polar front, an environmental setting characterized byhigh seasonal biological productivity and relatively agile bot-

tom waters (Østby and Nagy, 1982; Lukashina, 1987; Korsunand Polyak, 1989; Steinsund and others, 1994).

Nonion labradoricum (Pl. 2, Fig. 10) occupies a distinctzone extended across the study area at intermediate distancesfrom the rivers (Fig. 21). A similar zonal pattern of distributionoccurs in the Barents Sea, where the habitat of N. labradori-cum is stretched along the Polar front (Steinsund and others,1994). This occurrence is consistent with a preference for freshphytodetritus as a food source (Cedhagen, 1991). The infaunallife mode of N. labradoricum (Corliss, 1991; Corliss and VanWeering, 1993; Hunt and Corliss, 1993) further suggests theaffinity of this species for environments with at least seasonallyelevated concentrations of food in sediment, although N. la-bradoricum is also capable of surviving prolonged starvation(Cedhagen, 1991).

Stainforthia loeblichi (Pl. 2, Fig. 19) has a distribution pat-tern resembling that of N. labradoricum (Fig. 22). Similar dis-tributions of these species have been also observed elsewhere(Steinsund and others, 1994; Wollenburg and Mackensen,1998b). Stainforthia species are opportunistic, taking advan-tage of pulses of high seasonal productivity (Alve, 1995; Gus-tafsson and Nordberg, 2001). This feeding pattern is corrobo-rated by an observation that a morphologically similar, and tax-onomically related, foraminifer Bulimina exilis shows prefer-ence to fresh organic detritus (Caralp, 1989).

Miliolidae combine Pyrgo williamsoni, Triloculina trihe-dra, and several species belonging to the genera Quinquelo-culina and Miliolinella. No clear pattern can be recognized inthe distribution of this group, possibly because of a combina-tion of several individual ecological preferences; however, it isrecognizable as intermediate in terms of distance from the riv-ers (Fig. 23).

Elphidium subarcticum (Pl. 1, Figs. 8–12) is the only el-phidiid in our data set that tends to proliferate more in the river-distal than river-proximal areas (Fig. 24). E. subarcticum hasbeen reported as widely occurring throughout the high- andtemperate-latitude shelves (e.g., Loeblich and Tappan, 1953;Todd and Low, 1966; Lukina, 1977, 1990; Culver and Buzas,1980); the distribution has not shown a clear pattern, possiblybecause of varying taxonomic approaches to this species. Acharacteristic ecological trait that has been noted for E. su-barcticum is an epifaunal, commonly attached habitat (Poag,1982; Korsun and Polyak, 1989; Korsun and others, 1994).

259BENTHIC FORAMINIFERAL ASSEMBLAGES FROM THE SOUTHERN KARA SEA

PLATE 1Scale bars are 100mm unless otherwise indicated. Sampling stations are shown in Fig. 8. 1a–b E. incertum, juvenile, st. 2202. 2 E. incertum, st.

2401. 3a–c Elphidium incertum, st. 4402; b bar 5 50mm; c bar 5 25mm. 4 E. incertum, st. 2701. 5a–b E. incertum, tuberculate morphotype, st.k32; b detail of an area in front of aperture, bar 5 10mm. 6a–e E. incertum, tuberculate morphotype, st. k32; c area in front of aperture; bar 510mm; d umbilical area with numerous diatoms; bar 5 100mm; e diatoms Aulacosira granulata (Ehr.) between the tuberculi; bar 5 10mm. 7 E.incertum, tuberculate morphotype, st. k32. 8 Elphidium subarcticum, juvenile, st. 2701. 9 E. subarcticum, st. 4398. 10 E. subarcticum, st. 2701.11a–b E. subarcticum, st. 4398; b bar 5 50mm. 12 E. subarcticum, st. 2703.

260 POLYAK, KORSUN, FEBO, STANOVOY, KHUSID, HALD, PAULSEN, AND LUBINSKI

FIGURE 13. Distribution of Elphidium incertum. Area with maxi-mal frequencies is shaded.

River-distal Species

Islandiella norcrossi (Pl. 2, Fig. 13), combining I. norcrossisensu stricto and a closely related, intergrading species I. he-lenae, shows a distinct preference to river-distal areas (Fig. 25).This distribution pattern is consistent with observationsthroughout the Arctic shelves showing that I. norcrossi/helenaeis associated with relatively high and stable bottom salinities(e.g., Mudie and others, 1983; Korsun and Hald, 1998). Datafrom the Barents Sea indicate that this species has maximumfrequencies in the areas with seasonal sea ice and thus may berelated to summer ice-edge productivity (Korsun and Polyak,1989; Steinsund and others, 1994).

Melonis barleeanus (Pl. 2, Fig. 9) is clearly distanced fromrivers and is mostly localized in the deep Novaya ZemlyaTrough (Fig. 26). Elsewhere, M. barleeanus is typically asso-ciated with normal marine salinities, absent or seasonal ice cov-er, and fine sediments accumulated in shelf depressions and onthe continental slopes (e.g., Mudie and others, 1983; Macken-sen and others, 1985; Hald and Steinsund, 1992; Korsun andPolyak, 1989; Korsun and others, 1994; Wollenburg and Mack-ensen, 1998a). Species of Melonis have been shown to dwellmostly infaunally, feeding on buried organic detritus (e.g., Cor-liss, 1985, 1991; Korsun and others, 1994; Wollenburg andMackensen, 1998b; Mackensen and others, 2000). Moreover, ithas been suggested that Melonis can thrive on somewhat al-tered organic matter (Caralp, 1989).

Cibicides lobatulus also flourishes in river-distal areas, but,in contrast to M. barleeanus, is associated with coarser sedi-ments at shallower depths with more current activity (Fig. 27).Cibicides, as well as other plano-convex foraminifers, areknown as clinging epifaunal suspension feeders, populating ar-eas with vigorous bottom waters (e.g., Nyholm, 1961; Lutzeand Thiel, 1987; Korsun and Polyak, 1989; Hald and Stein-sund, 1992; Korsun and others, 1994; Wollenburg and Mack-ensen, 1998a).

Astrononion gallowayi (Pl. 2, Fig. 11) has a distributionsimilar to that of C. lobatulus, even more strictly adhering tothe river-distal, shallow area along Novaya Zemlya (Fig. 28).The association of A. gallowayi with elevated current activity

and coarse sediments, observed on the shelf and upper slopeof the Barents Sea, attests to the attached epifaunal life modeof this species (Korsun and Polyak, 1989; Korsun and others,1994; Wollenburg and Mackensen, 1998a).

Other Species

Elphidium excavatum formaclavata (Pl. 2, Figs. 6, 7) isthe most abundant calcareous benthic foraminifer in the studyarea, and the only species that shows no recognizable distri-bution pattern (Fig. 29). E. e. clavata is known to be wide-spread on the Arctic shelves, including extreme environments,such as near tidewater glacier fronts (Leslie, 1965; Lukina,1977, 1990; Mudie and others, 1983; Polyak and Korsun, 1989;Hald and others, 1994; Hald and Korsun, 1997; Korsun andHald, 1998, 2000). The exceptional ability of this species toadapt to harsh environments may be related to its high nutri-tional and habitat versatility, and capability of quickly coloniz-ing seafloor areas temporarily unsuitable for life (Corliss, 1991;Corliss and Van Weering, 1993; Linke and Lutze, 1993; Wol-lenburg and Mackensen, 1998b; Alve, 1999). The southwarddistribution of E. e. clavatum in the Barents Sea is limited bywater temperatures above ;48C and/or by the winter sea-iceboundary; this is probably due to competition from speciesadapted to more stable feeding conditions. In near-shore watersaffected by riverine fluxes, E. e. clavatum spreads to temperatelatitudes, grading into warmer-water forms of E. excavatum(Brodniewicz, 1965; Lutze, 1965; Feyling-Hanssen, 1972; Wil-kinson, 1979; Miller, 1982).

DISCUSSION

RIVER-PROXIMAL ASSEMBLAGES

The dominant foraminifers in river-proximal assemblages arethe elphidiids, with Elphidium incertum and Haynesina orbi-culare being most frequent (Figs. 13–14). Elphidium excava-tum f. clavata is also abundant here and even occurs in theextreme up-river samples; however, its frequencies are evenlydistributed throughout the entire study area, showing only aslight increase near the estuaries (Fig. 29). The two other el-phidiid species characteristic of river-proximal environmentsare Elphidiella groenlandica, which occurs exclusively nearestuaries, and Elphidium bartletti (Figs. 16–17). The more off-shore optimum of E. bartletti may be related to the presenceof coarser-grained sediment (cf. Fig. 6) or the interplay betweensalinity, food availability, and sedimentation rate with distancefrom the rivers. Among foraminifers other than elphidiids,those with strongest affinity to river-proximal environments arepolymorphinids (Fig. 15). Buccella spp. also have elevated fre-quencies in the vicinity of the estuaries (Fig. 18).

We infer that river-proximal assemblages are adapted to en-vironments with high seasonal, possibly pulsed, fluxes of foodand sediment. Elphidiids and Buccella spp. that constitute themajority of river-proximal assemblages have supplementary ap-ertures, which allow a quick exertion and withdrawal of largevolumes of cytoplasm for efficient capture and digestion ofvarious food objects (Brasier, 1982; Alexander and Banner,1984). In particular, the runoff delivers plentiful terrigenous,partially labile organic matter and riverine algae, which die outwhen entering the marine waters (Lisitzin and others, 1995;Boucsein and others, 1999). Numerous fresh- or brackish-waterdiatoms found on the tests of E. incertum at the Yenisey es-tuary provide evidence for such a feeding strategy (Pl. 1, Figs.6d–e). The enhanced tuberculation of these tests may be a mor-phological adaptation to feed on diatoms by crushing their frus-tules between the tuberculi (Alexander and Banner, 1984). In-terestingly, E. incertum has an asymmetric distribution with

261BENTHIC FORAMINIFERAL ASSEMBLAGES FROM THE SOUTHERN KARA SEA

PLATE 2Scale bars are 100mm unless otherwise indicated. Sampling stations are shown in Fig. 8. 1, 2 Haynesina orbiculare, st. 4398. 3 H. orbiculare,

st. k19. 4 Elphidium bartletti, st. 2102. 5 Elphidium bartletti, st. 2102. 6 Elphidium excavatum f. clavata, st. 2704. 7 Elphidium excavatum f.clavata, st. 2701. 8 Elphidiella groenlandica, st. 2601, bar 5 1mm. 9 Melonis barleeanus, st. 2701. 10 Nonion labrodoricum, st. 2701. 11Astrononion gallowayi, st. 2701. 12 Cassidulina reniforme, st. 2701. 13 Islandiella norcrossi, st. 2701. 14 Buccella frigida, st. 2701. 15 Buccellafrigida, st. 2701. 16 Buccella hannai arctica, st. 2701. 17 Buccella hannai arctica, st. 2701. 18 Trifarina fluens, st. 2701. 19 Stainforthia loeblichi,st. 2701.

respect to the two estuaries, being most frequent in the Yeniseyarea (Fig. 13). This asymmetry may reflect a higher river-bornproductivity in front of the Yenisey estuary (cf. Vedernikov andothers, 1995; Nothig and Kattner, 1999), which, in turn, is pos-sibly caused by higher fluxes of organic matter from the Yen-isey as opposed to higher fluxes of total sediment from the Ob(Gordeev and others, 1996).

Another factor that most likely affects the adaptations of the

river-proximal assemblages is a high variability of the physicalenvironment, especially in terms of salinity and sediment flux-es. Although mean bottom salinities near the estuaries aremostly between 20 and 30 psu, point measurements at the es-tuary mouths have shown values as low as 5–10 psu. The sur-vival of foraminifers in this environment may be related to theirincreased mobility within the sediment that allows them to es-cape extreme freshening events by burrowing into the substrate,

262 POLYAK, KORSUN, FEBO, STANOVOY, KHUSID, HALD, PAULSEN, AND LUBINSKI

FIGURE 14. Distribution of Haynesina orbiculare. Area with max-imal frequencies is shaded.

FIGURE 16. Distribution of Elphidiella groenlandica. Area of oc-currence is shaded.

FIGURE 15. Distribution of Polymorphinidae. Area with maximalfrequencies is shaded.

FIGURE 17. Distribution of Elphidium bartletti. Area with maximalfrequencies is shaded.

and sediment depositional pulses by moving upwards (cf. Wet-more, 1988; Langer and others, 1989). E. excavatum is knownfor its ability to thrive at various depths in and upon sediment(Corliss, 1991; Corliss and Van Weering, 1993; Linke and Lu-tze, 1993; Wollenburg and Mackensen, 1998b); high burrowingskills have been reported for some other shallow-water elphi-diids (Banner and Culver, 1978; Langer and others, 1989). Sup-plementary apertures of elphidiids and Buccella spp. facilitatetheir motility in comparison with foraminifera that extend pseu-dopodia only through the primary aperture (Kitazato, 1988). Amorphological trait that is also most likely related to enhancedmobility is longitudinal grooves between the tuberculi in the

apertural areas; these grooves are well-developed on the tuber-culate E. incertum population from the Yenisey estuary (Pl. 1,Figs. 5b, 6b–c), and similar grooves are characteristic of relatedforaminifers E. albiumbilicatum, H. germanica, and some H.orbiculare (Knudsen, 1971; Hansen and Lykke-Andsersen,1976; Banner and Culver, 1978). Such grooves serve as path-ways for pseudopodial trunks extended for locomotion andfeeding (Alexander and Banner, 1984; Kitazato, 1992). Anotheradaptation of shallow-water and river-proximal foraminifers tounstable environments is encystment, which has been reportedfor E. incertum (Linke and Lutze, 1993).

263BENTHIC FORAMINIFERAL ASSEMBLAGES FROM THE SOUTHERN KARA SEA

FIGURE 18. Distribution of Buccella spp. FIGURE 20. Distribution of Trifarina fluens. Area with maximalfrequencies is shaded.

FIGURE 19. Distribution of Cassidulina reniforme. Area with max-imal frequencies is shaded.

FIGURE 21. Distribution of Nonion labradoricum. Area with max-imal frequencies is shaded.

RIVER-INTERMEDIATE ASSEMBLAGES

The most characteristic foraminifers of intermediate assem-blages, Nonion labradoricum and Stainforthia loeblichi, avoidmore extreme river-proximal or river-distal environments (Figs.21–22). Both N. labradoricum and S. loeblichi, or closely re-lated species, have been associated with elevated seasonal pro-ductivity (e.g., Cedhagen, 1991; Gustafsson and Nordberg,2001), which is consistent with their distribution near the PolarFront in the Barents Sea (Steinsund and others, 1994). Themostly infaunal habitat of these species supports their prefer-ence of at least temporarily high concentrations of food in sed-iment. Trifarina fluens, generally rare in the study area, hasmaximal frequencies adjacent to those of N. labradoricum and

S. loeblichi; this is similar to distributions in the Barents Sea(cf. Steinsund and others, 1994). Maximal frequencies of T.fluens consistently occur in the vicinity of the Polar Front, al-though at somewhat shallower depths than N. labradoricumand S. loeblichi (Østby and Nagy, 1982; Lukashina, 1987; Kor-sun and Polyak, 1989). We infer that the distribution of thesethree species reflects a relatively high seasonal productivity atintermediate distances from estuaries, combined with a reducedsediment flux, which results in a high concentration of food inbottom sediments. Alternatively, the intermediate zone may re-flect a shorter, more pronounced productivity spike than in thevicinity of the estuaries, controlled by the sea-ice melting. Sa-linity is also a likely factor preventing the propagation of these

264 POLYAK, KORSUN, FEBO, STANOVOY, KHUSID, HALD, PAULSEN, AND LUBINSKI

FIGURE 22. Distribution of Stainforthia loeblichi. Area with max-imal frequencies is shaded.

FIGURE 24. Distribution of Elphidium subarcticum. Area withmaximal frequencies is shaded.

FIGURE 23. Distribution of Miliolidae.FIGURE 25. Distribution of Islandiella norcrossi. Area with max-

imal frequencies is shaded.

species towards the river mouths (cf. Cedhagen, 1991; Alve,1995; Hald and Korsun, 1997). Other species with elevatedfrequencies in the intermediate Kara Sea associations, Cassi-dulina reniforme, Elphidium subarcticum, and miliolids, haveless accentuated distributions, but mostly avoid river-proximalareas (Figs. 19, 23–24). This pattern may be caused by theirinability to survive reduced and fluctuating salinities or com-petition from foraminifers adapted to near-estuarine feeding en-vironments. The epifaunal, commonly attached life mode of E.subarcticum may explain the avoidance of river-proximal en-vironments because of turbid bottom water and high seasonalsediment fluxes.

RIVER-DISTAL ASSEMBLAGES

The most river-distal assemblages do not approach the es-tuaries and are associated with mean bottom salinities mostly.34.5 psu (Figs. 25–28). These assemblages fall into twogroups readily differentiated by water depths. The deeper-watergroup populates the Novaya Zemlya Trough and is character-ized by Islandiella norcrossi and especially Melonis barleean-us. The association of M. barleeanus with an area of low bi-ological productivity seems to contradict the commonly-heldview that this species indicates high-productivity environments(e.g., Wollenburg and Mackensen, 1998a,b). This apparent con-tradiction is resolved by the inference that M. barleeanus can

265BENTHIC FORAMINIFERAL ASSEMBLAGES FROM THE SOUTHERN KARA SEA

FIGURE 26. Distribution of Melonis barleeanus. Area with maxi-mal frequencies is shaded.

FIGURE 28. Distribution of Astrononion gallowayi. Area withmaximal frequencies is shaded.

FIGURE 27. Distribution of Cibicides lobatulus. Area with maxi-mal frequencies is shaded.

FIGURE 29. Distribution of Elphidium excavatum f. clavata. Shad-ing highlights the widespread occurrence of this species.

feed on organic detritus delivered with fine sediments fromshallow areas and deposited in sea-floor depressions, which isconsistent with its infaunal habitat (e.g., Corliss, 1985, 1991;Mackensen and others, 2000) and its ability to feed on alteredorganic matter (Caralp, 1989). In the Barents and Kara seasthis down-slope transportation of fine sediments is common,being enhanced by fall/winter bottom-water cascading withbrines formed during the ice freezing (cf. Honjo, 1990). I. nor-crossi also prefers relatively deep areas on the Arctic shelves,but not as consistently as M. barleeanus. The distribution of I.norcrossi appears to be more closely associated with seasonalice cover, and thus with ice-margin productivity processes

(Korsun and Polyak, 1989; Steinsund and others, 1994). Theother river-distal foraminiferal group, represented by Cibicideslobatulus and Astrononion gallowayi, is characteristic of theshallow zone adjacent to Novaya Zemlya (Figs. 27–28). Bothspecies, known as epifaunal grazers and filterers, obviouslytake advantage of vigorous bottom waters on this narrow stripof shallow seafloor, which is largely covered by coarse sedi-ment and rock exposures and supports epifaunal communitieswith a relatively elevated biomass (Zenkevich, 1960; Matishovand others, 1989). Patches of C. lobatulus occurrences farthereast may be connected with locally intensified bottom currents.A strong salinity control is expected for the river-distal assem-

266 POLYAK, KORSUN, FEBO, STANOVOY, KHUSID, HALD, PAULSEN, AND LUBINSKI

blages, possibly associated with epifaunal, attached life modeof C. lobatulus and A. gallowayi and with a reduced mobilityof infaunal stenohaline foraminifers, as demonstrated for M.barleeanus (Mackensen and others, 2000).

One other characteristic feature of the river-distal assem-blages is the presence of planktonic foraminifers, which rarelyoccur closer to the estuaries and appear to be related to theinflow of Barents Sea waters. However, it is not known whetherthis distribution of planktonic foraminifers is controlled pri-marily by salinity, feeding preferences, or life cycle that mayrequire a stratified water column (e.g., Volkmann, 2000).

CONCLUSIONS

Hydrographic variables, such as surface and bottom salini-ties, bottom temperatures, and oxygen content in the southernKara Sea reveal a strong interrelationship. This pattern reflectsthe overwhelming control of riverine fluxes of freshwater andassociated dissolved and suspended matter on the environmentsin the water column and on the sea floor. Accordingly, thedistribution of benthic foraminifers shows an orderly succes-sion along a gradient from the Ob and Yenisey estuaries to-wards the open sea. The most commonly occurring foraminif-eral species, or groups of species, fall into three types of as-semblages: river-proximal, intermediate, and river-distal. Weinfer that the differences between these assemblages are con-trolled by their feeding patterns, depending largely on riverinefood and sediment fluxes, and by bottom salinities.

River-proximal assemblages are characterized by various el-phidiids (Elphidium incertum, Haynesina orbiculare, Elphi-diella groenlandica, and Elphidium bartletti), polymorphinids,and, less markedly, by Buccella spp. We believe that at leastsome of these foraminifers are adapted to specific feeding con-ditions near estuaries, which have seasonally elevated fluxes ofboth organic matter and total sediment, including river-bornlabile organics. Enhanced mobility of some foraminifers, suchas elphidiids, in sediment is also inferred to be an adaptationto the extreme temporal variability of river-proximal environ-ments. The intermediate position between river-proximal andriver-distal environments is most commonly occupied by Non-ion labradoricum and Stainforthia loeblichi, with adjacent ar-eal habitats of Trifarina fluens. This position may be connectedwith seasonally elevated concentrations of food in sedimentsdue to a combination of relatively high productivity and low-ered sediment load or, alternatively, to a productivity spike atthe ice margin zone. Bottom salinity likely exerts at least partialcontrol on the distribution of these species and other interme-diate foraminifers, such as Cassidulina reniforme, Elphidiumsubarcticum, and miliolids. Salinity-controlled distribution isalso implied for the river-distal assemblages, which occupy twodistinct western areas of the southern Kara Sea: the deep No-vaya Zemlya Trough and the narrow bank adjacent to NovayaZemlya. The trough assemblages are characterized by Islan-diella norcrossi and Melonis barleeanus. The latter is believedto feed on organic matter transported from shallower areas, andthus indicates the deposition of fine sediment delivered bydownslope water movement. The characteristic foraminifers ofthe shallow river-distal area are Cibicides lobatulus and As-trononion gallowayi, both of which are epifaunal species pre-sumably specializing on bottom-water filtration.

The overall results on foraminiferal distribution in the south-ern Kara Sea enhance our understanding of foraminiferal ecol-ogy and provide a framework for paleo-environmental recon-structions in river-influenced Arctic marine settings. Develop-ment of more accurate and comprehensive proxy models re-quires quantitative multi-annual data on seasonal biologicalproductivity in the Kara Sea, which undoubtedly has a major

control on foraminiferal life patterns. Multi-seasonal samplingto study the influence of large productivity and hydrographicchanges on distributions of living foraminifers would providethe most accurate information for understanding proxy rela-tionships (cf. e.g., Korsun and Hald, 2000; Gustafsson andNordberg, 2001).

ACKNOWLEDGMENTS

This is Byrd Polar Research Center publication No. 1263 supportedby the US NSF grants OPP-9529133 and 9725418. We are grateful toO. Kijko and other colleagues from VNII Okeangeologia and P. P.Shirshov Institute of Oceanology, Russia, who have been involved incollecting and processing of materials used in the publication. Com-ments by S. Ishman helped to improve the manuscript.

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Received 15 June 2001Accepted 12 October 2001

APPENDIX 1

FAUNAL REFERENCE LIST

Most foraminiferal species used in this study are well-defined tax-onomically by previous works; we provide a short reference list thatexemplifies our taxonomic views. We mostly refer to recent, readilyavailable monographic descriptions; see citations therein for extendedsynonymy and references to earlier descriptions. Because of varying

269BENTHIC FORAMINIFERAL ASSEMBLAGES FROM THE SOUTHERN KARA SEA

systematic approaches to Elphidium incertum and E. subarcticum, wediscuss these species in more detail.

Astrononion gallowayi Loeblich and Tappan, 1953 (Pl. 2, Fig. 11)Astrononion gallowayi: Loeblich and Tappan, 1953, p. 90, pl. 17,

figs. 4–7; Knudsen, 1971, p. 266, pl. 10, figs. 10–12.Buccella frigida (Cushman, 1922) (Pl. 2, Figs. 14, 15)

Buccella frigida: Knudsen, 1971, pl. 8, figs. 12–14; pl. 19, fig. 1;Østby and Nagy, 1982, pl. 2, fig. 2.

Buccella hannai (Phleger et Parker) subsp. arctica Voloshinova, 1960(Pl. 2, Fig. 16, 17)

Buccella hannai arctica: Voloshinova, 1960, p. 286, pl. 8, figs. 2–4.Cassidulina reniforme Nørvang, 1945 (Pl. 2, Fig. 12)

Cassidulina reniforme: Sejrup and Guilbault, 1980, p. 79, fig. 2F–K.Cibicides lobatulus (Walker et Jacob, 1798)

Cibicides lobatulus: Knudsen, 1971, pl. 9, figs. 9–14; Østby andNagy, 1982, pl. 3, fig. 11.

Elphidiella groenlandica (Cushman, 1933) (Pl. 2, Fig. 8)Elphidium groenlandicum: Knudsen, 1971, p. 275, pl. 12, figs. 1–8;

pl. 21, figs. 1–3.Elphidiella groenlandica: Loeblich and Tappan, 1953, p. 106, pl.

19, figs. 13, 14.Elphidium gorbunovi: Shchedrina, 1946, p. 144, pl. 4, fig. 21 (name

widely used in Russian literature)Elphidium bartletti Cushman, 1933 (Pl. 2, Figs. 4, 5)

Elphidium bartletti: Loeblich and Tappan, 1953, p. 96, pl. 18, figs.10–14; Knudsen, 1971: p. 271, pl. 11, fig. 6–9; pl. 20, figs. 1–4.

Elphidium goesi: Shchedrina, 1946, p. 144, pl. 4, fig. 20 (namewidely used in Russian literature).

Elphidium excavatum (Terquem) forma clavata Cushman, 1944 (Pl.2, Figs. 6, 7)

Elphidium clavatum Cushman: Loeblich and Tappan, 1953, p. 98,pl. 19, figs. 8–10; Knudsen, 1971, pl. 11, figs. 10–13; pl. 20, figs.5–8.

Elphidium excavatum: (Terquem) forma clavata Cushman: Feyling-Hanssen, 1972, pls. 1, 2.

Elphidium incertum (Williamson, 1858) (Pl. 1, Figs. 1–7)E. incertum: Buzas, 1966, p. 592, pl. 72, figs. 1–4 (not 5–6); Knud-

sen, 1971, p. 277, pl. 12, figs. 11–12; pl. 21, fig. 8, 9.E. asklundi: Knudsen, 1971, p. 270, pl. 10, figs., 20–21, pl. 11, figs.

1–5.

Discussion: E. incertum sensu stricto is characterized by a com-pressed test, slightly lobate outline, depressed, slightly curved sutureswith irregularly spaced ponticuli, and some degree of tuberculation inthe umbilicus and along the sutures. A population from the Yeniseyestuary mouth, tentatively identified as E. incertum, differs from atypical E. incertum by the expanded tuberculation forming a star-shaped figure in the umbilical area and along the sutures (Pl. 1, Figs.6–7). The same feature characterizes E. albiumbilicatum (Weiss), aclosely related species morphologically and ecologically (Hansen andLykke-Andsersen, 1976; Banner and Culver, 1978). Similar to E. alb-iumbilicatum, tuberculate E. incertum specimens are relatively small(maximal diameter ,0.4 mm), a feature possibly resulting from fastreproductive turnover rates at the sites with pulsed high food fluxes.Farther off the estuary mouth, E. incertum s.s. (with little tubercula-tion) may grow to sizes .0.6 mm; similar overgrown forms, whichoften acquire double rows of pores, have been identified as E. asklundi.We admit that the tuberculate morphotype from the Yenisei estuarymay be closer to E. albiumbilicatum than to E. incertum, however wefound it difficult to make a conclusion based on the existing material,in which most tests have been corroded by dissolution to some degree.Moreover, the systematic volume of E. albiumbilicatum lacks claritywith respect to its distinction from E. incertum and/or E. subarcticum.

Due to this uncertainty, the tuberculate forms of E. incertum/albium-bilicatum in some samples from the southern Kara Sea have beenpreviously identified as E. subarcticum (Paulsen, 1997).

Elphidium subarcticum Cushman, 1944 (Pl. 1, Figs. 8–12)Elphidium subarcticum: Loeblich and Tappan, 1953, p. 105, pl. 19,

figs. 5–7; Buzas, 1966, p. 593, pl. 92, figs. 7–10; Knudsen, 1971,p. 280, pl. 13, fig. 3–7; pl. 22, fig. 9.

Elphidium frigidum: Loeblich and Tappan, 1953, p. 99, pl. 18, figs.4–9; Østby and Nagy, 1982, pl. 3, fig. 12.

Elphidium hallandense Brotzen: Hansen and Lykke-Anderson,1976, p. 14, pl. 11, fig. 1.

E. magellanicum: Knudsen, 1971, p. 279, pl. 12, figs. 15–16.

Discussion: Elphidiids, which we refer to as E. subarcticum, havebeen identified under several names. We believe that the morphologicalvariability of E. subarcticum reflects different age stages and ecolog-ical conditions, rather than interspecific differences (cf. Todd and Low,1967). Juvenile specimens typically have a smooth outline and a star-shaped tuberculated area (Pl. 1, Fig. 8), similar to that of E. albium-bilicatum. In adult foraminifers, chambers become more inflated andthe tuberculation forms wide bands along the sutures, extending to theperiphery (Pl. 1, Figs. 9–12). Extreme forms, often identified as E.frigidum or E. magellanicum, have a distinctly lobate outline and mayhave small grooves transverse to the sutures (Pl. 1, Fig. 10); theseforms are typically found at sites with agile bottom water. In our ma-terial, E. subarcticum mostly have 5–6 chambers in juvenile specimensand 7–8 chambers in adults, as opposed to E. incertum/albiumbilica-tum, which typically have at least 8 chambers, even in juvenile tests.The widely used name E. subarcticum should be probably considereda junior synonym of E. magellanicum or E. frigidum.

Haynesina orbiculare (Brady, 1881) (Pl. 2, Figs. 1–3)Elphidium orbiculare: Loeblich and Tappan, 1953, p. 102, pl. 19,

figs. 1–4.Protelphidium orbiculare: Knudsen, 1971, p. 289, pl. 14, figs. 8–11,

pl. 24, figs. 6–8.Islandiella helenae Feyling-Hanssen and Buzas, 1976

Islandiella helenae: Feyling-Hanssen and Buzas, 1976, text figs.1–4.

Cassidulina teretis: Loeblich and Tappan, 1953, p. 121, pl. 24, figs.3–4.

Islandiella norcrossi (Cushman, 1933) (Pl. 2, Fig. 13)Islandiella norcrossi: Knudsen, 1971, pl. 8, figs. 1, 2.Cassidulina norcrossi: Loeblich and Tappan, 1953, p. 120, pl. 24,

fig. 2.Melonis barleeanus (Williamson, 1858) (Pl. 2, Fig. 9)

Nonion barleeanum: Knudsen, 1971, pl. 9, figs. 15–18; Østby andNagy, 1982, pl. 3, fig. 15.

Nonion zaandamae (van Voorthuysen): Loeblich and Tappan, 1953,pl. 15, figs. 11, 12.

Nonion labradoricum (Dawson, 1860) (Pl. 2, Fig. 10)Nonion labradoricum: Knudsen, 1971, pl. 10, figs. 1, 2; Østby and

Nagy, 1982, pl. 3, fig. 17.Stainforthia loeblichi (Feyling-Hanssen, 1954) (Pl. 2, Fig. 19)

Stainforthia loeblichi: Østby and Nagy, 1982, pl. 1, fig. 20.Virgulina loeblichi Feyling-Hanssen: Knudsen, 1971, p. 238, pl. 7,

figs. 1–5.Bulimina exilis Brady: Loeblich and Tappan, 1953, p. 110, pl. 20,

figs. 4, 5.Trifarina fluens (Todd, 1947) (Pl. 2, Fig. 18)

Trifarina fluens: Knudsen, 1971, pl. 7, figs. 12–15; Østby and Nagy,1982, pl. 1, fig. 21.

Angulogerina fluens: Loeblich and Tappan, 1953, p. 112, pl. 20, figs.10–12.

270 POLYAK, KORSUN, FEBO, STANOVOY, KHUSID, HALD, PAULSEN, AND LUBINSKI

APPENDIX 2. Environmental data and foraminiferal occurrences. Dashes indicate absence of reliable data; crosses (X) indicate foraminiferalspecies presence in low-abundance samples.

Stationno. (cf.Fig. 8)

Longi-tude E

LatitudeN

Waterdepth, m

Summersurfacesalinity,

psu

Summerbottomsalinity,

psu

Summerbottom

tempera-ture, 8C

Winterbottomsalinity,

psu

Winterbottom

tempera-ture, 8C

Oxygencontent,

ml/l

Oxygencontent,

%

Sandcontent(.0.063mm), %

Totalbenthic

foramin-ifers no./g

Cal-careousbenthic

foramini-fers, %

Plank-tonic

foramini-fers, %

Cal-careousbenthic

fora-miniferscounted

21022104220222042207

61.6866.2566.1764.8167.84

69.8069.4270.2971.5774.02

272920

12057

29.527.428.428.518.6

34.131.432.034.133.7

0.53.01.9

20.721.1

34.533.633.734.034.0

21.921.821.821.521.5

7.77.57.87.27.1

9999

1008983

5513393452

1130154816

451018

414

0.1

0.2

19998

1292855

22092305231424012501

72.6974.1078.1279.6880.81

73.1172.5272.8875.4272.90

2516131415

6.24.2

10.017.48.8

25.221.517.833.430.3

20.20.72.4

21.420.5

18.415.722.433.029.1

20.720.521.121.521.4

6.06.77.27.06.9

7078848080

17—74

9—

180121

22

71100

36

870

2025

825042507260126032701

80.2581.3977.2275.3469.94

73.6374.3475.1576.0176.41

4043447570

10.213.416.421.625.6

31.332.433.134.034.7

21.121.221.521.521.3

29.129.831.832.934.2

21.521.321.421.421.4

6.16.67.47.47.2

7077848685

2830282156

12143354

146

4413191994

0.4

2

9034

151174171

27032704270627082709

64.8762.1159.4857.5356.72

75.2875.2974.3673.4473.06

33072366075

22.627.328.128.128.5

34.734.934.934.934.7

21.421.521.621.621.5

34.935.135.034.934.8

21.421.421.621.721.7

7.37.17.27.07.1

8782848284

21579

636

32212630

180779

3193959312

0.4

0.8

0.1

160236232238164

27122715271727192721

59.5556.8455.8559.0756.62

72.6172.3571.5971.6971.14

98332

53165

85

29.428.528.429.628.7

34.734.534.234.634.3

21.521.521.221.421.2

34.634.634.534.434.5

21.621.721.721.621.7

7.37.37.47.47.5

8687898990

281133

118

10763462483

334

301818

0.1

0.1

17127

24461

184437743794380438143824383

58.0359.9759.9358.0264.0064.33

70.9872.2272.6272.6274.5674.37

236131106375

72100

28.629.328.928.624.524.5

34.234.634.734.734.534.5

21.121.521.521.621.321.3

34.534.534.634.734.834.8

21.821.621.621.721.421.4

7.57.47.37.27.37.3

918887858586

614—

7——

69

138121831

63100

1312

2 49100

016

22

43844385438643874388

64.7564.6064.5764.5764.62

73.9373.3372.6971.9971.02

168119

70152

75

24.726.627.728.128.7

34.434.334.334.434.0

21.321.221.221.120.5

34.734.534.443.034.1

21.421.421.421.421.5

7.37.37.37.17.4

8787878693

——

521

156

12412

7

972089

00

12015

15543894390439143934394

64.5064.5464.8663.1560.75

70.5470.0269.7870.3470.62

99102

46216138

28.528.328.328.328.2

33.933.532.734.334.6

0.11.32.3

20.321.3

34.234.234.234.434.4

21.721.821.821.821.7

7.57.67.57.67.6

96100101

9694

1426

33

1313432710

999843

968 4

1443981021588

43954397439843994400

72.9872.9779.9079.8579.89

74.2375.9976.0274.9974.25

30150

624129

12.620.920.116.014.6

32.334.233.833.132.6

21.421.521.421.421.3

26.932.733.832.330.4

21.321.421.421.521.5

6.67.37.16.96.5

7585818075

—3

251118

22

589

11

70969490

070

44113382

44014402440344054411

79.9579.8879.9383.4382.65

74.0073.5473.0071.7071.83

3539263029

14.08.9

10.80.61.1

32.530.428.68.17.7

21.220.920.4

8.37.7

29.928.629.212.813.9

21.521.421.420.121.4

6.35.96.96.06.2

7369817577

2290.4

——

24100.4

98100100

100

415125

04

44144416441714051407

73.5273.0973.5058.2860.74

73.6571.7470.9272.7172.25

251823

380120

9.61.20.4

28.728.9

29.34.91.2

34.734.6

20.94.05.2

21.621.5

22.812.7

8.634.734.5

21.020.420.321.721.5

6.36.96.97.27.4

7380818488

5————

0.40.10

2115

100100

1

123001

t4t5t6t10t13

66.8667.1267.4266.5766.13

74.2574.2674.2674.1974.13

15770

188122

79

19.619.318.820.120.7

34.334.334.134.434.4

21.221.221.221.221.2

34.534.434.334.534.6

21.521.521.521.521.4

7.27.27.17.27.2

8686858686

—————

1073

2382

399289

10098

3992

177199195

t18t19t20b122b196

68.1667.9367.6378.5280.80

74.2874.2774.2775.9775.22

5090

1057141

17.518.118.519.817.4

33.433.834.034.033.3

21.121.121.221.521.4

33.934.034.233.732.6

21.521.521.521.421.4

7.07.07.17.26.8

8383848279

—————

15121311

2

8798911595

1741961811019

271BENTHIC FORAMINIFERAL ASSEMBLAGES FROM THE SOUTHERN KARA SEA

APPENDIX 2. Extended.

Stationno. (cf.Fig. 8)

Astrono-nion gal-lowayi,

%

Buc-cellaspp.,

%

Cassi-dulinareni-

forme,%

Cibi-cidesloba-tulus,

%

Elphi-diellagroen-

landica,%

Elphi-dium

bartletti,%

Elphi-diumexca-vatum

clavata,%

Elphi-diumincer-tum,%

Elphi-dium

subarc-ticum,

%

Hayne-sina

orbicu-laris,

%

Islan-diellanor-

crossi,%

Melonisbarle-eanus,

%

Mili-olidae,

%

Nonionlabra-dori-cum,

%

Poly-morphi-nidae,

%

Stain-forthialoeb-lichi,

%

Tri-farinafluens,

%

21022104220222042207

1 175.94.9

16

5293.8

11225.5

8

5.5

332418

2.79.1

6.58.8

422.7

3

2111

172

168.1

31

0.524

1.622

1.814

1.8

124.9

3.68.13.6

22092305231424012501

29

XX

11

X

2.3

X

19

XX

10

X

16

XX

1.4 6.8

XX

25042507260126032701 13

12121144.1

4021404523

6

33

4.6941.7

23151711

7.6

3.31213

1.11.2 2.3

7.891.39.2

22.96.4 1.2

4.535.37.50.6

3

1.11.2

1.260.71.70.6

30.7

100.6

1.2

0.627032704270627082709

3.4345.51.8

7.55.91.73.41.8

7.51815222.4

3.83

242621

2.5

1436

0.91121

0.40.40.4

6011

4.315

6.1

0.6

0.40.4

2.513

4.351.8

1.92.11.32.9

37

0.83.90.4

0.6

0.40.4

0.40.40.4

1.30.41.3

0.40.40.4

27122715271727192721

23

1.6

1.27.42.94.91.1

4.1194.5

5214

0.6

221.62.2

4.93.3

7119

1.66.6

71511

1.2

6.6

0.63.7

104.9

31

0.62215

45

2.93.726.63.3

0.6

0.46.6

2.30.81.60.5

7

3.30.5

1.2

0.5437743794380438143824383

4.11

X

1619 3

1016

X

219

8.23

3918

X

2 6.15

X

44.1 2

86.1

43844385438643874388

2.1X

1.9

32

8.4 1.9

39X

50 4.5 14

4.1X

6.5

16X

3.2X

8.4 1.3X

43894390439143934394

1.51.422.5

4.5

194429

X24

0.50.7 58

3140

31

0.7

5.7

4.91.56.2

13

4.92

11

2.3

5.613

5.6

14

0.71

1.1

2.811.6

0.70.51.6

1.1

1.43

4.543954397439843994400

0.21172.16.7

29212430

0.5

1.1

2.7

10

29393426

1.1

6.7

1.411

3.3

5.229

6.7

2773.21.1

1.1

3.3

0.2

1.1

1.1

1.1

2.53.21.1

0.5

44014402440344054411

X

X

2229

X X

4927

X

X

2014

X2

7.320

X

X

3.93.9

44144416441714051407

XX

XX

XX

X

t4t5t6t10t13

1.12.62.25.640.5

5113163113

5.40.60.50.5

2.6

2.313.1

1354365172

2.2911

2.63.3

2.64.33.422.1

2.6

1941

2.6

0.6

0.5

5.1

4.51

1.10.50.5

2.61.1

10.5

0.50.5

t18t19t20b122b196

5.74.13.3

303333

0.50.60.5

X

3.43.10.6XX

454843

X

10.6

X

4.6

7.7XX

4.63.15.5

X

10.6

1.1

X

1.13.11.1

X

0.6

272 POLYAK, KORSUN, FEBO, STANOVOY, KHUSID, HALD, PAULSEN, AND LUBINSKI

APPENDIX 2. Continued.

Stationno. (cf.Fig. 8)

Longi-tude E

LatitudeN

Waterdepth, m

Summersurfacesalinity,

psu

Summerbottomsalinity,

psu

Summerbottom

tempera-ture, 8C

Winterbottomsalinity,

psu

Winterbottom

tempera-ture, 8C

Oxygencontent,

ml/l

Oxygencontent,

%

Sandcontent(.0.063mm), %

Totalbenthic

foramin-ifers no./g

Cal-careousbenthic

foramini-fers, %

Plank-tonic

foramini-fers, %

Cal-careousbenthic

fora-miniferscounted

b399b259n1n13n23

67.6363.1757.1759.6262.10

72.7372.6672.1873.7574.49

9363

499315320

24.628.628.528.628.3

33.834.434.634.834.8

20.621.321.521.521.5

33.834.534.634.934.9

21.621.421.721.621.5

7.37.37.47.27.1

8887878483

—————

310———

96100

———

11

192833364

7n41p1p2p3p4a

71.6061.8665.6266.2465.49

75.8469.9669.6669.3370.65

223195

312423

20.429.328.227.329.0

34.034.232.231.232.9

21.50.32.63.21.0

32.734.534.133.633.9

21.421.921.821.821.7

7.37.77.67.57.7

8699

102100

98

—6

75—75

—1744

26022

—24

51

12

0.7 14812929

759

p5p7p9p10p11.1

65.8372.9873.3073.3078.58

71.0073.0073.9874.4574.31

2327302731

29.35.6

11.413.714.2

32.826.331.432.331.9

1.020.521.321.421.3

33.817.625.528.029.6

21.620.621.221.321.5

7.75.96.46.77.0

9868737780

9115

59584

26132

537

9

92

6116

7

8310

19711631

p12p14p35p36p39

80.1381.0674.6673.4572.20

73.6173.9176.3876.5074.99

4541

101104

27

10.111.323.323.716.4

31.332.134.334.532.7

21.121.221.521.421.5

28.929.333.433.530.3

21.521.421.421.421.4

6.06.57.47.47.3

7076868684

44—504685

158

353842

41256

298

203142

p41p44p48p50

76.6080.4085.2683.50

76.1675.7775.2475.00

64414448

21.419.619.517.8

34.133.732.432.9

21.521.421.121.3

33.533.430.730.6

21.421.421.221.3

7.57.07.06.9

86808280

34765016

20233625

9261124

5913778

109p51p77p87p102

79.6780.0179.1068.98

75.0073.0572.5574.00

39219

17

16.010.79.4

15.0

33.129.616.830.7

21.420.7

2.820.7

32.229.525.333.1

21.521.421.121.5

6.96.87.17.2

80798483

3353294

1137

433

484

8323

16521

34494

p107k1k10k12

65.0173.1874.0874.29

73.9873.9172.5072.18

200291513

24.011.04.13.4

34.431.221.215.6

21.321.2

0.71.9

34.725.015.614.7

21.421.120.520.5

7.36.46.76.8

87737879

14—

10

39370.31

423

100100

21541346

k17k19k21

73.7379.0381.01

72.6974.0074.00

213042

4.813.811.3

25.031.732.2

20.121.321.2

16.428.629.5

20.621.421.4

6.56.76.5

767876

53

—

24

10

506265

50111135

k24k27k30k32k42

79.9280.0980.3481.4881.67

73.5372.8972.5172.0973.90

4119141032

8.910.97.02.3

11.0

30.629.123.212.531.8

21.020.4

1.75.6

21.0

28.628.826.421.027.8

21.421.421.220.621.2

5.96.97.06.36.5

6980817776

—1

—2

—

430.5

146

61100

95100

45

11411520

151119

k43k46k47k48k49

82.8177.2073.7573.1572.89

73.7174.0072.5872.9673.21

3227182930

9.212.74.55.66.9

31.431.223.227.127.1

20.821.2

0.220.720.6

25.726.816.217.619.5

21.121.320.520.620.8

6.77.56.65.96.0

7785776870

——

115

6

3328

15

5848972228

6958785372

k50k52k55k56k58

72.9572.6675.6275.4874.84

73.6174.0073.2272.8973.65

2831141524

9.411.28.47.49.0

29.731.327.625.628.6

21.021.420.620.220.7

22.925.820.219.120.8

21.021.220.820.720.9

6.26.77.27.27.0

7276818279

1634———

3397

359

644398

10025

17712311010448

273BENTHIC FORAMINIFERAL ASSEMBLAGES FROM THE SOUTHERN KARA SEA

APPENDIX 2. Continued, Extended.

Stationno. (cf.Fig. 8)

Astrono-nion gal-lowayi,

%

Buc-cellaspp.,

%

Cassi-dulinareni-

forme,%

Cibi-cidesloba-tulus,

%

Elphi-diellagroen-

landica,%

Elphi-dium

bartletti,%

Elphi-diumexca-vatum

clavata,%

Elphi-diumincer-tum,%

Elphi-dium

subarc-ticum,

%

Hayne-sina

orbicu-laris,

%

Islan-diellanor-

crossi,%

Melonisbarle-eanus,

%

Mili-olidae,

%

Nonionlabra-dori-cum,

%

Poly-morphi-nidae,

%

Stain-forthialoeb-lichi,

%

Tri-farinafluens,

%

b399b259n1n13n23

1.1

0.51.2

246.8X

104.63

13

0.5 191.2

1826

19X

4.2 1714

6.148

5.28

X

1120

2.361

7.5X

1.26.35.8

0.53.5 5.8

2.3

n41p1p2p3p4a

152.3

47

4.13.9 2.3

0.7

7.2

8.7

4529

3.1X

4.9 6.8

2

7.2

1.6

0.7

24X

14

1.437

2

1.6

1.43.1

20

106.1

0.70.8

X

166.9

p5p7p9p10p11.1

8.6X

12

2.9

0.5X

9.2

29

222022

X5.6

19

7.1

24

13

X0.5

2.9

23X

1765

2.9

X

p12p14p35p36p39

7.8

X3.24.7

X23

3.5

2.3

17

2312

11XX

7

X

7

11X

436.3

X9.4

X16

2.5

X6.34.7

3.2

p41p44p48p50

3.4151.19.4 0.8

1.10.8

2432.2

21

8.51.4

1910

1.78.1

137.9

0.8

3.512

2.65.4

3.7

3.7

138.7

138.3

8.52.23.74.6

5.1

3.73.7

101422

1.5

18p51p77p87p102

6.7

7.5

3.6X

1.2X

5.81

43X

0.35.4

5.5X

0.324

31

5611 5.5

4.2

1734 1

0.6 3.6 0.6X

20

p107k1k10k12

X48

X1.9 1.9

X X13

X59

22X

5.6

39

X1.9

X3.7X

2.2

X

k17k19k21

82.73

45.4

43

23.62.2

280.7

209

39

816

2.2

3630

3

42.73

181.83

k24k27k30k32k42

3.511

X

9.2

73.5

15

1.8

2.5

5.3

2.5

4674

X

18

180.9

9831

8.82.6X

1.7

2.6

7.6

1.8

0.8

1.87.8X

10k43k46k47k48k49

5.2191325

145.2

1.95.6

12172.61.91.4

2.95.2 29

406454

4114

1.95.6

162122

7.55.6

2.9

1.33.81.4

7.23.4

155.71.4

k50k52k55k56k58

234718

23

1.1150.9

2.3

208.3

0.6

1

5815685535

5.17.30.91.9

10

7.38.97.3

148.3

1.61.818.3

2.32.42.76.76.3