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Sea Ice Algae in the White and Barents Seas: Composition and Origin

Sea Ice Algae in the White and Barents Seas: Composition and Origin

Sea ice in the White and Barents : composition and origin

Tatjana N. Ratkova & Paul Wassmann

To examine algae populations, three expeditions (in March 2001, April 2002 and February 2003) were conducted in the Guba Chupa (Chupa Estuary; north-western White ), and one cruise was carried out in the open part of the in April 2003 and in the northern part of the in July 2001. algae and composition and abundance and the content of sediment traps under the land-fast ice in the White Sea and annual and multi-year pack ice in the Barents Sea were investigated. The community in land-fast sea ice was dominated by pen- nate diatoms and its composition was more closely related to that of the underlying sediments than was the community of the pack ice, which was dominated by fl agellates, dinofl agellates and centric diatoms. Algae were far more abundant in land-fast ice: motile benthic and ice-benthic spe- cies found favourable conditions in the ice. The pack ice community was more closely related to that of the surrounding water. It originated from plankton incorporation during sea ice formation and during seawater fl ood events. An additional source for ice colonization may be multi-year ice. Algae may be released from the ice during brine drainage or sea ice melting. Many sea ice algae developed spores before the ice melt. These algae were observed in the above-bottom sediment traps all year around. Three possible fates of ice algae can be distinguished: 1) suspension in the water column, 2) sinking to the bottom and 3) ingestion by herbivores in the ice, at the ice–water interface or in the water column.

T. N. Ratkova, Shirshov Institute of Oceanology, Academy of Sciences of , Nakhimovsky Ave. 36, 117997, Moscow, Russia, [email protected]; P. Wassmann, Norwegian College of Fishery Science, University of Tromsø, NO-9037 Tromsø, Norway.

High concentrations of organisms in polar sea ice Grossmann 1998). There are several hypotheses have been well documented (e.g. Horner 1985; regarding the origin and fate of sea ice commu- Lizotte 2003). Sea ice is inhabited by diverse nities (Horner 1985). Sieving of water by densely communities, including bacteria, algae, protists packed ice crystals has been observed repeated- and metazoans (e.g. Melnikov 1997). Often the ly and appears to constitute an important mech- fl ora and fauna are not evenly distributed in the anism for accumulation of algae cells on the ice ice, but occur in specifi c microhabitats in differ- under-surface (Syvertsen 1991; Melnikov 1997). ent parts of the ice fl oes (Horner 1985; Syvertsen The composition of sea ice algae off the shelves 1991; Gradinger 1999). Such communities have suggests that this population derives from pelagic been studied in detail, but the current knowl- algae inhabiting underlying water masses or from edge of the biological processes involved during sea ice algae at the ice edge or polynyas (Syvert- sea ice formation and melting are still inadequate sen 1991; Druzhkov et al. 2001). In shallow water (Gradinger & Ikävalko 1998; Weissenberger & areas benthic algae may be included in the suc-

Ratkova & Wassmann 2005: Polar Research 24(1–2), 95–110 95 cession cycle (Poulin 1990; Gogorev 1998). The salinity of the White Sea ice is low (Krell et Through various research programmes we al. 2003), and we deem that the algae were not studied and compared the ice fl ora of the White being exposed to osmotic stress during melt- and Barents seas, two inadequately stud- ing. In the Barents Sea, ice cores were collected ied with regard to ice biota. We investigated in with an ice auger (diameter 9 cm). The lowermost particular the peculiarities of the vertical distri- 20 - 30 cm of each ice core was melted in double bution of the sea ice algae under different con- its volume of fi ltered seawater at low tempera- ditions and the succession of this distribution tures. Samples from the water column below the during the late winter/early spring in the land-fast ice were also obtained in both regions (Appen- ice in the White Sea. The differences in the algae dix). The volume of the sea ice and water sam- species composition in different types of ice and ples ranged from 100 to 4500 ml, according to the the relationships between taxa within the ice and abundance of the algae. To investigate the pos- water column were also quantifi ed. sible importance of sea ice algae for the vertical fl ux of biogenic matter, cylindrical sediment traps were deployed below the ice: in the White Sea Materials and methods (Guba Chupa) the traps were preserved with for- maldehyde and exposed for a week at 20 m depth. Three cruises were conducted to the Guba Chupa Traps were also deployed above the bottom in the (Chupa Estuary; north-western White Sea) in Bay (depth 280 m) and nine sam- February 2003, March 2001 and April 2002. ples (each representing one month) were taken One cruise was carried out in the open part of from August 2002 to May 2003. In the Barents the White Sea (April 2003), where the stations Sea, traps were deployed without preservation for were located in the Marginal Ice Zone (MIZ) in one day at 30 m depth . The height/diameter ratio the southern part of Gorlo (north-eastern White of the traps was 3.11 for the White Sea and 3 for Sea). One cruise was carried out in the MIZ of the Barents Sea. Temperature and salinity were the northern part of the Barents Sea in July 2001 measured with standard CTD profi lers. (Table 1). Ice cores from the White Sea were All samples were preserved with a glutardial- obtained with a ring corer (diameter 14.5 cm) and dehyde–lugol–ethanol solution and developed divided into three or four sections: upper 10 cm, according to Ratkova & Wassmann (2002). Small lower 3 - 5 cm, and a middle part, which was cut fl agellates were counted in a Fuchs-Rosenthal into two parts if the total ice thickness exceeded chamber at 600× magnifi cation prior to any con- 40 cm. The sections were melted at low temper- centration of samples. After they had settled, atures (< 2 °C) without addition of fi ltered water. larger algae were counted in chambers with rul-

Table 1. Biomass (mg C m–3) of the sea-ice algae (“algae”) in the lowermost layer of the ice in the Barents (5 - 34 cm of 100 - 135 cm cores) and in the White Sea (5 - 10 cm of 37 - 56 cm cores) and of phytoplankton (“phyto”) below the ice.

White Sea Barents Sea White Sea (land-fast ice) (pack ice) 77° 50' N, 78° 20' N, 82° 00' N, 65° 40' - 66° 10' N, 66° 20’N, 29° 45' E 27° 20' E 26° 00' E 40° 10' - 40° 50' E 33° 40' E 3 July 6 July 9 July 19–20 April 8 February 18–26 March 6–8 April 2001 2001 2001 2003 2003 2001 2002 algae phyto algae phyto algae phyto algae phyto algae phyto algae phyto algae phyto Diatoms 7.58 5 - 49.2 1 - 254.6 1 - 44 - 11 - 1.49 0. 07 - 94 - 1 - 1136 - 1 - 44 7 7 478 12 0.31 598 64 35188 94 Dino- 0.49 34 - 14.0 25 - 11.0 1 - 1.3 - 21.7 0.01 - 0.49 0.03 - 3.1 - 0.02 - 24.5 - 1 - fl agellates 80 33 2 1.06 0.18 37.5 1 178.6 28 Other 17.0 82 - 86.8 82 - 76.5 32 - 36 - 27 - 4.4a 0.5 - 8.6 - 11 - 3.8 - 1 - fl agellates 299 173 74 49 94 2.2a 35.7 359 61.7b 525b Total 28.3 154 - 150 117 - 343.8 35 - 87 - 39 - 6.49 0.12 - 115.9 - 15 - 1164 - 3 - 407 218 83 565 109 2.69 674.1 444 35428 647 a According Sazhin et al. in press. b According Sazhin et al. 2004.

96 Sea ice algae in the White and Barents seas ings, at 300× magnifi cation in a 0.06 ml chamber –1.2 °C directly beneath the ice (thickness 34 - 52 and at 150× magnifi cation in a 1.0 ml chamber. The cm); both parameters increased with the depth. carbon content of the algae was calculated accord- In April 2003 the depth of the snow cover ranged ing to Strathmann (1967) for diatoms with a cell from 10 to 20 cm on different ice fl oes. The ice volume > 3000 µm3, and according to Menden- fl oes, which remained intact after a storm event, Deuer & Lessard (2000) for all other protists. showed no signs of surface melting. However, considerable ice melting occurred from the sides and from below, due to relatively warm water. The Results lower part of the ice cores (thickness 45 cm) was semi-transparent, granular and had large caverns. Physical environment The middle part was greyish, opaque and dense. The upper part of the ice layer was not much dif- The temperature of the water in the White Sea ferent from the middle part, though it was softer. seldom reached the freezing point, and the ice In the water column, salinity and temperature developed mainly from the surface (Krell et al. varied little from the surface to the bottom. From 2003; Pantyulin 2003). The ice was thin during the north-west part of the Gorlo Strait (66° 10' N; all of the expeditions (thickness 34 - 57 cm) and 40° 10' E), where most of the water is from the often fl ooded with seawater. Granular snow ice Barents Sea, to the south-east part of the strait dominated the entire ice column at all times in the (65°40' N; 40°50' E), where White Sea water dom- White Sea. Only in March 2001 and in February inates, the temperature increased from –1.52 to 2003 was columnar ice observed in the middle –1.08 °C and the salinity decreased from 29.7 ‰ part of the ice cores. The sea ice structure was to 27.2 ‰ psu (Kosobokova et al. 2004). determined by visual observation of the ice core, A peculiar feature of the physical oceanogra- but was supported by investigation of the crystal phy in the MIZ of the northern Barents Sea in structure of thin ice core sections (February and July 2001 was a 20 m thick layer of meltwater April 2002) (Krell et al. 2003). (–1 to 0.4 °C; psu 31 ‰) above the Water The winter of 2001 was unusually mild and ice (< –1 °C; psu 34 ‰). The ice conditions in the formation did not take place until February. The investigated fl oes varied from annual pack ice ice was rather porous, granular and white in the fl oes (thickness about 1 m) to multi-year pack ice upper and in the lowermost parts and columnar (thickness > 1.35 m). Differentiation between the and grey in the middle part of the ice cores. The multi-year and annual ice was based mainly on ice was 44 - 57 cm thick and was covered with a ice thickness and the density of the Melosira arc- layer of snow which increased in thickness from tica mats observed by the divers. The snow cover ca. 10 cm on the fi rst day of the expedition to ca. was rather thin (< 10 cm). 16 cm a day later, after a snowfall. Below the ice there was a < 1 m thick brackish layer (psu < 15 ‰) Phytoplankton and sea ice algae: composition with a temperature of –1.2 °C—well above the freezing point. A total of 306 algae species (Appendix) were In April 2002 a < 1 m thick brackish layer (psu identifi ed in the ice, in the water and in the sedi- < 6 ‰, temperature: –1.2 °C) was encountered ment traps. In White Sea land-fast ice, 275 species below the ice; the sea ice below a thin snow cover were encountered. The White Sea pack ice was was granular, white-grey and semi-transparent, inhabited by fewer species (106), and only four and wide channels were observed in the lower of them were not also observed in the land-fast 10 cm of ice cores (thickness 34 - 54 cm). A ice. In the Barents Sea, 201 species were found. In brownish discolouration was observed at the low- general, the algae composition in the two regions ermost surface. was rather similar: 156 species, including 73 dia- In February 2003 the white, dull granular ice toms, 39 dinofl agellates, all silicofl agellates and was covered with a thick layer of slush (up to coccolithophorides and 31 other fl agellates were 15 cm) and snow (ca. 10 cm). In the middle part, observed in both regions. The main differences columnar semi-transparent ice was observed. were encountered among the pennate diatoms. In In the lowermost few centimetres, the ice was the White Sea land-fast ice, 110 pennate species opaque, white and granular. The water salinity were found, while only 49 and 52 species were was high (psu 26.1 ‰) and the temperature was found in the White Sea and the Barents Sea pack

Ratkova & Wassmann 2005: Polar Research 24(1–2), 95–110 97 ice, respectively. Phytoplankton and sea ice algae: abundance Most of the species were found both in the water column and the ice, but 50 species were In the White Sea land-fast ice, fl agellates domi- not observed in the ice. Most of these were ben- nated the phytoplankton carbon in all samples, but thic ones which only occasionally occurred in the diatoms dominated in the sea ice (Table 1). Flagel- water, but there were also some common plank- lates comprised < 25 % in the ice and 73 - 80 % in tonic species which were not found in the ice, the water (3.8 - 62 and 0.5 - 525 mg C m–3, respec- for example, the diatoms Chaetoceros borealis, tively). In February 2003 the species composition C. brevis, C. decipiens, Corethron criophylum, and abundance of diatoms and dinofl agellates in Coscinodiscus centralis, C. radiatus, Probos- the White Sea land-fast ice were rather similar to cia eumorpha, Rhizosolenia hebetata f. semispi- those in the annual ice of the Barents Sea in July na; the dinofl agellates Dinophysis contracta, D. 2001, i.e. centric diatoms dominated in a sparse arctica, Heterocapsa triquetra, Protoperidinium sea ice algal assemblage (Fig. 1). pallidum, P. pellucidum, P. pyriforme, Warnowia In March 2001 the species composition in the reticulata and a few other fl agellates. White Sea land-fast ice was quite different: barrel Some species were observed only in the ice: and other benthic and ice-benthic diatoms domi- 37 diatoms (e.g. Navicula algida, N. glacialis, nated the algae carbon in the ice. Benthic single- N. gelida, Nitzshia hybridae, N. polaris, 22 other celled pennate diatoms were most abundant in the pennate and 10 centric species) and 7 dinofl ag- lowermost few centimetres of the ice core on 18 ellates (e.g. Gymnodinium wulfi i, Karenia brevis, March before a snowfall (> 1 × 105 cells l–1) and Protoperidinium granii). in the upper 10 cm of the ice (Fig. 2) after the Diatoms and euglenophytes were represented snowfall on 26 March (2.5 × 105 cells l–1). These by more species in the ice (178 and 5, respective- species were rare in the water, where centric dia- ly) than in the water (154 and 4, respectively). All toms dominated (Fig. 1). In April 2002, Nitzschia other groups were represented by more species in frigida dominated the total carbon of diatoms and the water; except for chlorophytes, which were dinofl agellates in the sea ice and water column represented by the same number of species in the (Fig. 1). ice and in the water. Two types of White Sea pack ice were studied: The snow covering the ice demonstrated poor pack ice fl oes in the southern part of the Gorlo species diversity (44 species in the snow in com- Strait, probably formed far from the coast (“clean parison to 228 species in the ice). All the spe- ice”), and fragmented ice in the northern part of cies observed in the snow were also found in the the Gorlo Strait with characteristic brown miner- underlying ice. al insertions (“dirty” ice). Algae biomass in the The abundance of species also differed between “dirty” ice (407 mg С m–3) was close to the high- sea ice and the water column: sea ice algae species est values in the “clean” ice (87 - 565 mg С m–3). were less abundant in the water, where plankton The composition of the algal populations differed species had the higher abundance (Appendix). On the basis of morphological and ecological distinctions, some assemblages of the sea ice spe- Fig 1 (opposite page). Composition of the diatoms and dino- cies were selected for comparison: A) pennate ice fl agellates abundance in the lowermost part of the ice, in the plankton species that develop ribbon-shaped colo- upper part of the water column and in sediment traps in the northern Barents Sea in July 2001 and in the White Sea in nies (Fossula arctica, Fragilaria striatula, Fragi- February 2003, March 2001, April 2002, and in the lower- lariopsis spp., Pauliella taeniata and some species most part of the ice and in the upper part of the water column of Navicula and Nitzschia—hereafter “ribbon dia- in April 2003. “Ribbon” denotes plankton diatoms forming toms”); B) single-celled ice-benthic pennate spe- ribbon-shaped colonies; “barrel” is benthic single-celled dia- cies that sometimes develop barrel-shaped colonies toms forming barrel-shaped colonies in the ice; and “Associ- ated” stands for species found in association with Melosira in ice (Enthomoneis spp., Undatella cf. quadrata, arctica and Nitzschia frigida. Each bar represents the value of Navicula lineola—“barrel diatoms”); C) epiphytic the single sample in the Barents Sea and in March 2001 and species that are associated with Melosira arctica April 2003 in the White Sea. The axes showing biomass are and Nitzschia frigida (Synedropsis spp., Gompho- different. Each bar is the mean value from the 4 - 5 samples collected in April 2002 and in February 2003. Low biomasses nemopsis cf. exigua, Gomphonema septentriona- of algae in the White Sea in the water in April 2003 and in lis, Pseudogomphonema kamchaticum and Atteya the traps in February 2003 are indicated by numbers instead septentrionalis—“associated diatoms”). of bars.

98 Sea ice algae in the White and Barents seas Ratkova & Wassmann 2005: Polar Research 24(1–2), 95–110 99 100 Sea ice algae in the White and Barents seas considerably: pennate ice-planktonic species the abundance of Melosira arctica and N. frigida were dominant in the “clean ice”, while plankton- was higher in the ice. ic centric algae were dominant in “dirty” ice (Fig. The sediment trap content under the multi-year 1). Compared to the White Sea land-fast ice, pack ice in the Barents Sea was rather similar to the ice in the White Sea had higher concentrations of algae composition in the ice, in contrast to the fl agellates (Table 1). traps under the annual ice, where the species M. Sedimentation of algae was low in Guba Chupa arctica and N. frigida were sparse. (0.28 - 2.2 mg C m–2 day–1) and was dominated by plankton centric diatoms in February and March. In April, Nitzschia frigida was more abundant Discussion than centric diatoms. Planktonic centric diatoms dominated the vertical fl ux above the bottom in Sea ice properties the deepest part of Kandalaksha Bay, but the per- manent occurrence of sea ice algae, even during The temperature of the water in the White Sea the summer months, was remarkable. seldom reached the freezing point, and the ice In contrast to the rather low abundance of phy- developed mainly from the surface (Krell et al. toplankton below the ice in the White Sea, in the 2003; Pantyulin 2003). The ice was thin during Barents Sea, the biomass of phytoplankton was all expeditions (range: 34 - 57 cm) and was often two orders of magnitude higher than the biomass fl ooded by seawater. In the White Sea, ice orig- of sea ice algae (Fig. 1). Flagellates dominated inated mainly from snow: δ18O varied between the sea ice algae and phytoplankton carbon in –1.51 and –8.72 (Krell et al. 2003). The granu- all samples from the Barents Sea (Table 1). They lar snow ice dominated the entire ice column at comprised 60 - 90 % of the total (1.1 - 3.9 mg C m–3 all times in the White Sea. Only during the cold- in the ice and 30 - 300 mg C m–3 in the water). est part of the year (March 2001, February 2002 In the lowermost part of the annual ice, centric and February 2003) was columnar ice observed diatoms were abundant (> 50 % of total carbon of in the lowermost layer of the ice. Congelation diatoms and dinofl agellates). ice may only be found during the fi rst stages of Plankton algae dominated the sea ice assem- ice development in the White Sea (Melnikov et blage and the vertical fl ux in the Barents Sea. In al. in press). The ice melted from below because the water and sediment traps dinofl agellates were the under-ice water temperature never dropped the second most abundant group. Only one sea ice below –1.5 °C in the course of our investiga- species (Nitzschia frigida) was numerous in the tions. The snow removed the bulk salinity from traps. The composition of the sea ice algae pop- the brine channels and reduced the total sea ice ulation in the multi-year ice was rather similar salinity to psu 0 - 4 ‰. Thick snow cover insulat- to that of the sea ice algae in the White Sea in ed the ice from the cold air, and the temperature April 2002: N. frigida and ribbon diatoms com- in the ice was rather high (> –2 °C). Low salini- prised the bulk of the total diatom and dinofl ag- ty and the high temperature of the ice led to wide ellate carbon. brine channels and low salinity in the brine water However, in the water column of the Barents (Melnikov et al. in press). Sea, total carbon of diatoms was dominated by There are no data regarding the sea ice struc- centric species, whereas in the White Sea it was ture in the investigated of the Barents dominated by pennates, N. frigida and ribbon Sea. However, it is well known that congelation species. Total algae concentration was higher in ice dominates the total ice column in the Barents the water than in the ice in the Barents Sea, but Sea, as in other Arctic areas. Only the uppermost 10 cm may be represented by snow ice. Salinity of the brine water may be as high as psu 70 - 144 ‰ (Gradinger et al. 1999). In summer, the total salin- Fig 2 (opposite page). Vertical distribution of the sea ice dia- ity and temperature of the lowermost part of the toms in the White Sea in March 2001, April 2002 and Feb- ice (psu 3 - 5 ‰ and –1.2 oC) appear to be compa- ruary 2003. “Barrel” refers to benthic single-celled diatoms rable with the White Sea ice. forming barrel-shaped colonies in the ice; “Ribbon” is plank- ton diatoms forming ribbon-shaped colonies. The axes are the same within each column, but the left and right columns have different axes. Each bar represents a single sample.

Ratkova & Wassmann 2005: Polar Research 24(1–2), 95–110 101 Composition and abundance during ice formation and during fl ood events (Buck et al. 1998). However, they were not abun- Most of the species that were observed in the sea dant in the interior of the ice, but only in the upper ice were similar to those recorded from other parts and lower layers, where the ice is in contact with in the Arctic. In the high latitude Arctic this sim- the underlying water or fl oodwater. Centric dia- ilarity may be attributed to the long-range trans- toms are regarded as allochthonous for the ice port of ice (von Quillfeldt et al. 2003), but this realm. Thus, pennate diatoms dominate among explanation does not hold for the White Sea ice. the sea ice algae from the Chukchi, East Siberian The similarity between sea ice assemblages in the and Laptev seas (Okolodkov 1992). The lower part White Sea and in other ice-covered regions may of the annual sea ice in the northern Barents Sea be explained by a similar origin of the ice fl ora was dominated by ice-plankton and plankton dia- in all Arctic regions (Sazhin et al. 2004). Three toms. The sub-ice assemblage was dominated by types of sea ice organisms can be distinguished: ice-plankton (ribbon diatoms and Nitzschia frig- ice specialists, ice-benthic and ice-plankton spe- ida). The ice specialist Melosira arctica, the ice- cies. Additionally, plankton and benthic species benthic species (Enthomoneis spp., Diploneis lito- may also be observed in sea ice. The sea ice spe- ralis) and associated species were also observed. cialists were neither observed in bottom sedi- Planktonic algae dominated the water and sed- ments nor in plankton in summer, but they were iment traps. Only one sea ice species (N. frigi- found in the bottom water sediment trap, prob- da) was numerous in the traps. The sea ice com- ably due to resuspension and stirring up of the munity of the annual ice in the northern Barents sediment. As soon as the ice melted, sea ice spe- Sea included more planktonic algae than in the cialists decayed or developed resting spores (e.g. White Sea, but the same benthic species occurred Undatella cf. quadrata, Melosira arctica). in both areas. Closely related to these species were ice-ben- The diatom population in the lower part of the thic species (e.g. Diploneis litoralis, Enthomon- multi-year ice was dominated by ribbon diatoms eis spp., Navicula lineola), but these species were and by N. frigida. M. arctica developed into thick also observed in bottom sediments as active cells mats below the ice. The plankton diatom Chae- (Gogorev 1998). Benthic species may be includ- toceros socialis dominated the water below the ed into the sea ice during its formation in shallow ice, but in the upper few metres M. arctica was estuaries or bays. They may survive in the ice, also abundant. M. arctica was abundant in the but in contrast to the ice-benthic species, their sediment traps below the multi-year ice, in con- abundance is not high (e.g. Mastogloia spp., Pin- trast to those below annual ice, indicating that nularia spp., Triblionella litoralis). Most of these this species is primarily introduced to the Barents ice-benthic and benthic species were observed in Sea from the Arctic . Many resting spores the White Sea bottom sediments in March 2001 of M. arctica were observed in the water column (F. Sapozhnikov, pers. comm.) and in the plank- and in sediment traps. Evidently, part of the M. ton in the during the ice formation in arctica mats were detached from the lower sur- November 2003 (T. Ratkova, unpubl. data). These face of the ice. species were observed in the bottom water trap in Coastal sea ice of the White Sea forms in pro- the White Sea deep throughout the year (T. Ratk- ductive systems where a continuous nutrient ova, unpubl. data). supply from the water column (rivers, sediment, Ice-benthic species were not abundant in pack mixing by tidal currents) sustains high algal bio- ice, probably because they cannot recolonize ice mass, with diatoms as the dominating taxon (Krell from the bottom in deeper waters. The sea ice et al. 2003). Oceanic ice habitats of the Barents algae that inhabit the pack ice survive the summer Sea, however, are characterized by more regener- in the water column (ice-plankton algae) or in the ative food webs, with lower biomass and a higher multi-year ice (sea ice specialists). contribution of fl agellates (Gradinger 1999). The ice-plankton species were frequent in This illustrates the main difference between the land-fast and pack ice (e.g. ribbon diatoms and White Sea land-fast ice and White and Barents Nitzschia frigida, accompanied with Atteya sep- seas pack ice. These two different scenarios con- tentrionalis, Synedropsis hyperborea and Gom- tribute to the observed differences in composition phonema-like species). The plankton centric and abundance of the ice algae in these two types diatom species may be incorporated into the ice of sea ice.

102 Sea ice algae in the White and Barents seas The difference between the abundance of sea snowfall, they may have actively moved through ice algae in the White Sea and in the Barents Sea the brine channels to the upper part of the ice. may be attributed in part to the different timing of Consequently, on 26 March 2001 the highest bio- growth. In the northern Barents Sea the produc- mass of these species was observed in the upper 10 tivity of sea ice algae is highest in July (Kuznetsov cm of the ice. The same vertical distribution was & Schoschina 2003), but in the White Sea it is in also observed in February 2003, when the snow April (Ilyash et al. 2003). Our observations in the cover was exceptionally thick. The ice-plankton- Barents Sea were conducted at the end of sea ice ic and ice-benthic species may demonstrate new algae vegetation and before and during the max- morphological peculiarities when they live in ice. imum of sea ice algae development in the White Some of the species became longer (Fragilariop- Sea. sis cylindrus, F. oceanica, Nitzschia longissima); The species composition in the ice changes others (Enthomoneis spp, Undatella cf. quadrata little with the age of the ice, whereas the relative and Navicula lineola) developed large barrel-like abundance of each species may change marked- colonies. These morphological changes may indi- ly: plankton species, which are more abundant cate an adaptation to new conditions. and dominate total algae numbers and carbon in In March 2001 we also observed an upward young ice, may be replaced by ice species, which movement of the ice-benthic diatom Diploneis are more abundant in older ice. The composition litoralis. It had its highest abundance in the lower of the sea ice algae results primarily from the com- 5 cm of the ice core on 18 March and was dis- position of algae in the underlying water masses placed to the upper 10 cm by 22–26 March. We in regions that are not ice-covered during a part speculate that the vertical species succession, of the year, or from the composition of the sea ice which usually occurs over a time span of months algae community in the ice-edge or in polynyas (Syvertsen 1991), took place in a week in 2001 (Syvertsen 1991; Weissenberger 1998; Druzhkov because of the late development of the sea ice. et al. 2001). In shallow water areas benthic algae may also be included in the succession cycles (Poulin 1990; Gogorev 1998). The stickiness of Conclusion pennate diatoms (Riebesell et al. 1991) may par- tially explain their high enrichment rates. Usual- A total of 306 algae species were identifi ed in ice, ly the planktonic and benthic algae entrapped by water and sediment traps in the Barents and White the ice crystals in autumn (Syvertsen 1991; Mel- seas. In the White Sea land-fast ice, 275 species ni kov 1997; von Quillfeldt 1997) will be sparse were recorded. In the White Sea pack ice, species during the entire winter. They start their develop- were less numerous (106 species), and only four ment in spring (Zhitina & Mikhailovsky 1990). of these species were not observed in the land-fast However, if sea ice forms earlier (in October in ice. In the Barents Sea, 201 species were found. the northern Barents Sea), the entrapped algae In general, the algae composition in the two may develop immediately (Horner 1990; Druzhk- regions was rather similar. The main differences ov et al. 2001), overwintering as a well-organized were encountered among the pennate diatoms: in community. The timing of the development of the the White Sea land-fast ice, 110 pennate species sea ice algae community can be explained mainly were found, while only 49 and 52 species were by the light conditions and the taxonomic com- found in the White Sea and Barents Sea pack ice, position of the algae: benthic algae may be better respectively. Most of the species were found both adapted to lower irradiance and lower tempera- in the water column and in the ice, but a few spe- ture than planktonic ones (Gogorev 1998). cies were not observed in the ice. The algae com- munities of the ice and ice-covered waters in the The vertical distribution of sea ice algae White and Barents seas are highly variable in space and time (Sazhin et al. 2004; von Quillfeldt The benthic algae entrapped by the ice crystals et al. 2003). To understand the dynamics of these during ice formation in February 2001 may have algae assemblages, one must take into account the developed immediately in the lower part of the formation history of the ice. thin granular ice because the light conditions in The algae communities of the land-fast ice, newly formed ice are favourable for algae growth. dominated by pennate diatoms, are more closely When the irradiance decreased after a heavy related to the bottom sediments than the commu-

Ratkova & Wassmann 2005: Polar Research 24(1–2), 95–110 103 nity of the pack ice, which is dominated by centric References diatoms. The algae in the land-fast ice communi- ty are more numerous and variable than those of Buck, K. R., Nielsen, T. G., Hansen, B. W., Gastrup-Hansen, the pack ice. Motile benthic and ice-benthic spe- D. & Thomsen, H. A. 1998: Infi ltration phyto- and protozo- oplankton assemblages in the annual sea ice of Disco Island, cies fi nd favourable conditions in the ice because west Greenland, spring 1996. Polar Biol. 20, 377–381. of the close proximity and similarity between the Druzhkov, N. V., Druzhkova, E. I., Larionov, V. V. & Turak- bottom sediments and the sea ice interior (Gogor- ov, A. B. 2001: Sostav i vertikalnoe raspredelenie ledovoi ev 1998). The plankton and ice-plankton species mikrobioty v severnoy chasti Barentzeva morja v nach- ale zimnego perioda 1998 (1). (The composition and verti- fi nd stable illumination and refuge from graz- cal distribution of the ice algae communities in the north- ers in the ice. However, conditions here are less ern Barents Sea at the beginning of the winter 1998 [1].) favourable for plankton algae, which are well- In A. P. Lisitzin & M. E. Vinogradov (eds.): Opyt system- adapted to life in the water column, where algae nykh okeanologicheskikh issledovanyi v Arktike (Experi- circulate passively with the turbulent fl ow and ence of system oceanologic studies in the Arctic). Pp. 325– 343. Moscow: Scientifi c World Publ. where conditions for nutrient uptake are better. Gogorev, R. M. 1998: Dyatomovye pozdne-vesennego l’da v Algae living in ice, in contrast, must contend with Belom more (Bacillariophyta glaciei veris seri maris Albi). the laminar fl ow in the narrow channels of the ice, (Diatoms of the late spring ice of the White Sea.) 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Ratkova & Wassmann 2005: Polar Research 24(1–2), 95–110 105 Appendix Table continued from Abundance previous column. White Bar. Sea Sea )

The following table indicates the relative abun- 3 µ Ice dance, geographic ranges and ecology of the spe- Ice Snow (m Water Water Range Ecology cies recorded from ice cores and sub-ice water in vol. Cell the White Sea in February, March and April 2001– Caloneis sp. 1---- 03 and in the Barents Sea in July 2001. (Identifi - Campylodiscus fastuosus 42 000 Ab? M, --1-- cations are based on Krishtofovich & Proshkina- Ehrenberg Be Lavrenko [1949, 1950], Hendey [1964], Semina Chaetoceros affi nis Lauder 4600 Ab? M, N 1 - 1 - - [1974], Semina & Sergeeva [1983], Medlin & Prid- C. borealis Bailey 11 250 tAb M - - 1 - - dle [1991], Thomsen [1992], Snoeijs [1993], Snoe- C. brevis Schütt 1500AbM, N----1 ijs & Vilbaste [1994], Snoeijs & Potapova [1995], C. ceratosporus Ostenfeld 50AbM, N2-1-2 Snoeijs & Kasperovičienė [1996], von Quillfeldt C. compressus Lauder 600tAbM 1-1-1 [1996, 2000], Konovalova [1997], Tomas [1997], C. concavicornis Mangin 2200 Ab M 1 - 1 - - Okolodkov [1998], Snoeijs & Balashova [1998], C. danicus Cleve 7500 tAb B, N 1 - 1 - - Tuschling [2000], Ulanova [2003], Throndsen et C. debilis Cleve 600tAbM, N1-1-1 al. [2003] and von Quillfeldt et al. [2003].) Geo- C. decipiens Cleve 13 500c M --1-1 graphic ranges (in the column headed “Range”) C. diadema (Ehrenberg) Gran 3100 Ab M, N 1 - - 1 1 C. diversum Cleve 720 tb M, N - - 1 - - are: cosmopolitan (c), Arctic–boreal (Ab), bipo- C. fallax Proshkina-Lavrenko 1100- - 1---- lar (b), tropical–Arctic–boreal (tAb), tropical– C. furcellatus Bailey 200AbM, N1-1-1 boreal (tb) and tropical (t). Ecological categories C. gracilis Schütt 110AbM, N1-111 (“Ecology”) are: freshwater (F), brackish water C. holsaticus Schütt 720AbB, N1---- (B), marine (M), eurihaline (E), neritic (N), ice– C. invisibilis Gogorev 30 - M, In 2 - 1 3 - neritic (In), marine–neritic (Mn), epiphytic (Ep) C. laciniosus Schütt 400 tAb M, N 1 1 - - 1 and benthic (Be). Relative abundance (mean num- C. perpusillus Cleve 300tAbM, N----1 ber of cells for all available samples) categories C. similis Cleve 300AbM, N1---- are: 1 (< 1 104), 2 (1 104 - 1 105), 3 (1 105 - 1 106) C. simplex Ostenfeld 350tAbE, N131-1 and 4 (> 1 106 cells l–1. C. socialis Lauder 100c E, N23333 C. wighamii Brightwell 600AbE, N1---- Cocconeis costata Gregory 4600 Ab? M, N 1 - 1 - - C. pediculus Ehrenberg 1440 - B, Ep - - 1 - - Abundance C. scutellum Ehrenberg 9000 c? M, N 1 - 1 - - White Bar. C. stauroneiformis (Van 4050 - B, Ep - - 1 - 1 Sea Sea Heurck) Okuno )

3 Corethron criophyllum Cas- 25 200 c M - - 1 - - µ

Ice Ice tracane Range Snow (m Water Water Ecology Cell vol. vol. Cell Coscinodiscus asterom- cM--11- Division Chromophyta phalus Ehrenberg 1012 500 C. centralis Ehrenberg 844 000 c M - - 1 - - Class Bacillariophyceae C. concinnus W.Smith 1350 000 c M 1-1-- Achnanthes brevipes Agardh 4000c B, Be1-1-- C. radiatus Ehrenberg 42 300 c M - - 1 - - A. fl exella (Kütz.) Brun 9000 - F, Be - - 1 - - Ctenophora pulchella (Ralfs & 6370 Ab E, Be 1 - 1 1 - Achnantidium minutissima 250- F, Be1-1-- Kützing) Williams & Round (Kütz.) Czarm. Cyclotella choctawhatchea- 1700 Ab E, N 1 - 1 1 - Actinocyclus curvatulus 67 500 c M 1 - 1 - - na (Proshkina-Lavrenko) Ehrenberg Prasad A. octonarius Ehrenberg 48 000c M 1---- C. litoralis Lange & Syvert- 16 000 b E, N 1 - 1 - - Amphora spp. 1-1-1 sen Asterionella formosa Hassal 800 c F - - 1 - - C. striata (Kützing) Grunow 3000 Ab? E, N 1 - 1 - - Attheya septentrionalis 150 Ab M, 32131 Cylindropyxis tremulans 140 - - 1 - 1 - - (Øestrup) Crawford Ep, Hendey In Cylindrotheca closterium 450c E, N11111 Bacterosira bathyomphala 2200AbM, N1-1-1 (Ehrenberg) Lewin & Rei- (Gran) Syvertsen & Hasle mann

106 Sea ice algae in the White and Barents seas Table continued from Abundance Table continued from Abundance previous column. White Bar. previous column. White Bar. Sea Sea Sea Sea ) ) 3 3 µ µ Ice Ice Ice Ice Snow Snow (m (m Water Water Water Water Range Range Ecology Ecology Cell vol. vol. Cell vol. Cell Dactyliosolen fragilissimus 5100c?- 1---- Gyrosigma compactum Gre- 4300 - - 1 - 1 1 - (Bergon) Hasle ville Detonula confervacea (Cleve) 270AbM, N--1-1 G. fasciola var. tenuirostris 7000Ab?M, N1---- Gran (Grunow) Cleve Diatoma tenuis Agardh 800 - F 1 - 1 - - G . hudsonii Poulin & Car- 18 000 Ab M, In 1 1 - - - Didymosphaenia geminata 56 900 - F, Be - - 1 - - dinal (Lyngb.) M.Schmidt G. tenuissimum var. hyperbo- 3400 - M, N 1 - 1 1 - Diploneis didyma (Ehren- 10 000 Ab? B, N 1 - 1 - - rea (Grunow) Cleve berg) Ehrenberg Hannaea arcus (Ehrenberg) 3200 - F - - 1 - - D. litoralis var. litoralis 2300AbM, N2-111 Patrick (Øestrup) Cleve Hantzschia sp. --11- D. litoralis var. arctica 2700AbM, In1---- Haslea sp. 1---1 (Øestrup) Cleve Lauderia annulata Cleve 22 800 tb M 1 - - 1 1 D. litoralis var. clathrata 5300AbM, In1-1-- Leptocylindrus danicus Cleve 1200tAb?M, N1-1-1 (Øestrup) Cleve L. minimus Gran 600 tAb M 1 - 1 - - Ditylum brightwellii (West) 11 800 tb M 1 - 1 1 - Grunow Licmophora communis (Heib- 4100 Ab? M, N 1 - 1 - - erg) Grunow Entomoneis alata (Ehrenberg) 3000 - - 1 - 1 1 1 Poulin & Cardinal L. gracilis (Ehrenberg) 18 200 - M, N 1 - 1 - - Grunow E. kjelmanii (Cleve in Cleve 78 000 Ab M, In 1 1 1 - - & Grunow) Poulin & Car- Mastogloia sp. 1-11- dinal Melosira arctica Dickie 1500AbM, In1-121 E. kjelmanii var. subtilis 16 000AbM, In1-1-- M. moniliformis (O.F.Müller) 25 200 B, N1---- (Grunow) Poulin & Cardinal Agardh E. paludosa (W. Smith) 28 800 Ab B, In 1 - 1 1 - M. nummuloides Agardh 43 500 c M, N 1 - 1 - - Poulin & Cardinal Melosira sp. --1-- E. paludosa var. hyperbo- 29 400AbM, In1-1-- Meridion circularis (Grev.) 400 - F - - 1 - - rea (Grunow in Cleve & Agardh Grunow) Poulin & Cardinal Meuniera membranacea 15 000Ab- 1---- E. pseudopulex Osada & 23 600- - 1---- (Cleve) P.C. Silva Kobayasi Navicula algida Grunow 120 000 AbM, In1 --- E. punctulata (Grunow) 18 700 Ab B, In 1 - 1 1 - Osada & Kobayasi N. directa (W.Smith) Ralfs 9000 Ab - 1 - 1 - - Entomoneis sp. 25 200 1 - 1 - - N. distans (W.Smith) Ralfs 56 300Ab?Be1-1-- Eucampia groenlandica Cleve 1500AbM, N1-1-1 N. gelida Grunow 15 000AbM, In1---- Fallacia forcipata (Greville) 23 520 c M 1 - 1 - - N. glacialis Cleve 7300AbM, In1---- Stickle & Mann N. granii (Jørgensen) Gran 2700 Ab M, In 2 - 1 1 - Fossula arctica Hasle, Syvert- 1400AbM, In21131 N. cf. lineola Grunow 9050 Ab M, In 1 - 1 1 - sen & von Quillfeldt N. menisculus var. meniscus 2200- F 1---- Fragilaria striatula Lyngbye 2560AbM, In2111- (Schum.) Hust. F. ulna (Nitzsch) Lange-Ber- 7300- F 1-1-- N. microcephala Grunow 540- F 1---- talot N. monilifera Cleve 10 000Ab?M 1---- Fragilariopsis cylindrus 100b M, In21121 N. pelagica Cleve 1100AbE, N2-121 (Grunow) Krieger N. pellucidula Hustedt 7200AbM, In1---- F. oceanica (Cleve) Hasle 400AbM, In21111 N. septentrionalis (Grunow) 800 Ab M, N 1 - 1 - - Gomphonemopsis cf. exigua 1920 Ab? M, 21111 Gran (Simonsen) Medlin Ep, In N. superba Cleve 9600AbM, In1---- Grammatophora arctica 12000 Ab? M, N 1 - 1 - - N. transitans var. derasa 34 900Ab- 1-1-- Cleve (Grunow) Cleve G. oceanica (Ehrenberg) 9000 Ab? M, N - - 1 - - N. vanhoeffenii Gran 2200 Ab E, N 1 - 1 - - Grunow Nitzschia angularis W.Smith 3200 - - - - 1 - - Guinardia delicatula (Cleve) 7000 c M, N 1 - 1 - - N. dissipata (Kützing) 2250- F 1---- Hasle Grunow

Ratkova & Wassmann 2005: Polar Research 24(1–2), 95–110 107 Table continued from Abundance Table continued from Abundance previous column. White Bar. previous column. White Bar. Sea Sea Sea Sea ) ) 3 3 µ µ Ice Ice Ice Ice Snow (m Snow (m Water Water Water Water Range Range Ecology Cell vol. vol. Cell Ecology Cell vol. vol. Cell

N. frigida Grunow 4500AbM, In41131 P. seriata (Hasle) Hasle 3200 Ab M, --1-- N. hybrida Grunow 2400AbB, In1---- Mn N. longissima (Brebisson) 830b M, N1111- P. seriata f. obtusa (Hasle) 2200 Ab - 1 - 1 - - Ralfs Hasle N. neofrigida Medlin 19 000 Ab M, In 1 1 1 - - Rhabdonema arcuatum (Lyng- 49 500 Ab Ep 1 - 1 - - bye) Kützing N. pellucida Grunow 1100Ab?B 1---- Rhizosolenia hebetata f. semi- 37 500 Ab M, --1 N. polaris Grunow 6500AbM, In1---- spina (Hensen) Gran Mn N. promare Medlin 560AbM, In2111- Rhizosolenia setigera Bright- 18 000 c M, 1---- N. recta Hantzsch. 1400- F 1---- well Mn N. scrabra Cleve 12 000 Ab M 1 1 1 - - Rhoicosphenia curvata (Kütz- 4000 - B, N 1 - 1 - - ing) Grunow N. sigmoidea (Ehrenberg) 9000 - B 1 - 1 1 - Wm. Smith Skeletonema costatum (Gre- 200 c M, 21121 ville) Cleve Mn Odontella aurita Agardh 10 500c?B, N1-1-1 Stauroneis amphioxys Gre- 24 000Ab?N 1---- Paralia sulcata (Ehrenberg) 3300 c? M, 1-11- gory Cleve Be Stenoneis sp. 1---- Pauliella taeniata (Grunow) 1000 Ab E, 21131 Round et Basson Mn Synedropsis hyperborea 270AbM, In2-121 (Grunow) Hasle, Medlin & Pinnularia guadrataera var. 15 000 tAb M, N 1 - 1 - - Syvertsen baltica Grun Synedropsis hypeboreoides 250 Ab M, In 1 - 1 1 - P. semiinfl ata (Øestrup) Gran 5400AbM, In1 --- Hasle, Medlin & Syvertsen Plagiotropis lepidoptera 60 000 tAb M, N 1 - 1 - - Tabellaria binalis (Ehren- 4800- F 1-1-- (Gregory) Poulin & Cardinal berg) Grunow P. scaligera Grunow in Cleve 10 000 - - 1 - 1 1 - T. fenestrata (Lyngbye) Kütz- 30 000 - F 1 - 1 1 - & Grunow ing Planotidium delicatulum 200Ab?E, N1---- T. fl occulosa (Roth.) Kützing 18 700 - F - - 1 1 - (Kützing) Round & Bukht. Thalassionema nitzschioides 400 tAb M, 111- - Pleurosigma angulatum 6000tAb?B, N1111- (Grunow) Grunow & Hustedt Mn (Quekett) Wm.Smith Thalassiosira angulata (Gre- 4300 Ab M, 11111 P. clevei Grunow in Cleve & 35 000 Ab M, In 1 - 1 1 - gory) Hasle Mn Grunow T. anguste-lineata 12 000tAbM, N1-1-1 P. fi nmarchicum Cleve & 67 500 Ab? Mn 1 - 1 1 - (A.Schmidt) Fryxell & Hasle Grunow T. var. borealis 14 580 Ab M, 11111 P. formosum Wm.Smith 18 700 - - 1 - 1 - - Fryxell, Douc. & Hubb. Mn P. normanii Ralfs 4500c? - 1111- T. bioculata (Grunow) Osten- 18 000Ab?- 1---- Porosira glacialis (Grunow) 38 800b N 1-111 feld Jørgensen T. bulbosa Syvertsen 400Ab- 1-1-1 Proboscia eumorpha (Cast- 3200 c M, ----1 T. conferta Hasle 2000 tb - 2 1 1 - - racane) Takahashi, Jordan & Mn Priddle T. eccentrica (Ehrenberg) 23 400 tAb E, --1-- Cleve Mn Pseudogomphonema kamt- 7200 - Ep 1 - 1 2 - chaticum (Grunow) Medlin T. gravida Cleve 9000 b M, 1-1-- Mn P. septentrionale (Øestrup) 3200 Ab? M, 1---- Medlin Ep, T. hyalina (Grunow) Gran 6500 Ab M, 2111- In Mn Pseudo-nitzschia australis 3100 tb M, 1-1-1 T. hyperborea (Grunow) 25 000AbB, In1111- (Cleve) Heiden Mn Hasle & Lange P. calliantha (Hasle) Lund- 100 Ab M, 1-11- T. nordenskioeldii Cleve 2900AbE, N11111 holm, Moestrup & Hasle Mn Trachyneis aspera (Ehren- 160 000 Ab M, N 1 - 1 - - P. delicatissima (Cleve) 200 Ab M, 1-1-- berg) Cleve Heiden Mn Tryblionella litoralis 18 000 - M, 1-11- P. granii (Hasle) Hasle 30Ab?- 1-1-1 (Grunow) D.G.Mann Be P. pungens (Grunow & Cleve) 1400 c M, 1---- Undatella cf. quadrata (Bréb. 24 300 tAb? M, 1-11- Hasle Mn in Kütz.) Padd. et Sims Be

108 Sea ice algae in the White and Barents seas Table continued from Abundance Table continued from Abundance previous column. White Bar. previous column. White Bar. Sea Sea Sea Sea ) ) 3 3 µ µ Ice Ice Ice Ice Snow (m Snow (m Water Water Water Water Range Range Ecology Cell vol. vol. Cell Ecology Cell vol. vol. Cell

Class Dinophyceae G. simplex (Lohmann) Kofoid 190tAbN 1-1-1 Alexandrium insuetum Balech 1500tAb?N 1-112 & Swezy A. ostenfeldii (Paulsen) 147 000 tAb? N 1 - 1 - - G. wulfi i Schiller 4000tAbN 1---- Balech & Tangen Gyrodinium cf. aureolum 24 000 Ab - 1 - - 1 1 A. tamarense (Lebour) Balech 19 000 tAb? N 1 - 1 1 - Hulburt Amylax triacantha (Jør- 5000 Ab N - - 1 - - G. cohnii (Seligo) Schiller 4500Ab?- 1---- gensen) Sournia G. esturiale Hulburt 1700 c N - - 1 - - Amphidinium crassum Loh- 2300Ab?N 1-111 G. fusiforme Kofoid & Swezy 1620tAbMn1-111 mann G. lachryma (Meunier) 36 700AbMn1-1-1 A. fusiformis Martin 1050Ab?N 1-111 Kofoid & Swezy A. larvale Lindemann 190- E, N1-1-1 G. prunus (Wulff) Lebour 47 000 c - 1 - - - 1 A. latum Lohmann 1350Ab?N ----1 G. spirale (Berg) Kofoid & 17 000 c - 1 - 1 1 1 A. longum Lohmann 1300c N 1-111 Swezy A. sphenoides Wulff 1100AbM 1-1-1 Heterocapsa rotundatum 400c N 1-1-2 (Lohmann) Loeblich Ceratium fusus (Ehrenberg) 91 800 c M 1 - 1 - - Dujardin H. triquedrum (Lohmann) 6900 c B, N - - 1 - - Hansen C. lineatum (Ehrenberg) 46 900 tb M - - 1 - - Cleve Karenia brevis (Davis) 4000AbN 1---- G.Hansen & Moestrup Cochlodinium archimedes 1400AbM 1-111 (Pouchet) Lemmermann Karlodinium micrum (Lead- 1700- - 111- - beater & Dodge) J.Larsen Cochlodinium brandtii Wulff 8000 Ab Mn - - 1 1 - K. venefi cum (Ballantine) 900- - 11111 Cochlodinium schuetti 6000 - - 1 - 1 1 1 J.Larsen (Kofoid & Swezy) Shiller K. vitiligo (Ballantine) 1700- - 11111 Dinophysis acuminata Cla- 19 000 c N - - 1 - - J.Larsen parède & Lachmann Katodinium glaucum 2100 tAb N 1 - 1 1 - D. acuta Ehrenberg 18 000b M 1---- (Lebour) Loeblich D. arctica Mereschkowsky 9000 b N - - 1 - - Micracanthodinium claytonii 3800------1 D. contracta (Kofoid & 6000 tAb M - - 1 - - (Holmes) Dodge Skogsberg) Balech Oblea baculifera Balech 1700b - 1-1-- D. islandica Paulsen 36 000 Ab N - - 1 - - Oxyrrhis marina Dujardin 6500tAb?E, N1---- D. norvegica Claparède & 35 000 Ab N 1 - 1 - - Oxytoxum belgicum Meunier 5250 - - - - 1 - - Lachmann Peridinella catenata (Lev.) 4700 Ab N 1 - 1 1 - Diplopelta parva (Abé) Mat- 5900 Ab N 1 - 1 1 - Balech suoka Preperidinium meunieri 10 000t M 1-1-1 Enthomosigma peridinioides 1200 tAb? N 1 - 1 1 - (Pavillard) Elbrächter Shiller Pronoctiluca acuta (Lohm- 1600 tAb Mn - - 1 - - Glenodinium gymnodinium 50 000- B, N1---- ann) Schiller Penard P. pelagica Fabre-Domergue 9400c M ---11 Gonyaulax digitalis (Pouchet) 40 000 b Mn - - 1 - - Kofoid Prorocentrum balticum 400c M 1-111 (Lohmann) Loeblich G. grindleyi Reinecke 18 000 Ab N 1 - 1 1 - P. cordatum (Ostefeld) Dodge 1600tAbN 1-1-1 G. spinifera (Claparède & 9900 c Mn 1 - 1 - - Lachmann) Diesing P. micans Ehrenberg 6000tAbN 1-1-- Gymnodinium albulum Lin- 150- B, N11112 P. minimum (Pavillard) 720 c N 1 - 1 - - dermann Schiller G. arcticum Wulff 4000AbMn1-1-1 Protoperidinium bipes 2000c N 1-1-1 (Paulsen) Balech G. blax Harris 260 - F 1 - 1 - - P. brevipes (Paulsen) Balech 10 100AbN 1-1-1 G. frigidum Balech 13 500b N 1---1 P. depressum (Bailey) Balech 130 000 cM--1-- G. japonica Hada 400- N 1-111 P. granii (Ostefeld) Balech 66 000 c N 1 - - 1 - G. heterostriatum Kofoid & 4700 tAb? N - - 1 - - Swezy P. islandicum (Paulsen) 36 000AbN ----1 Balech G. lebourii Pavillard 108 000- - 1-1--

Ratkova & Wassmann 2005: Polar Research 24(1–2), 95–110 109 Table continued from Abundance Table continued from Abundance previous column. White Bar. previous column. White Bar. Sea Sea Sea Sea ) ) 3 3 µ µ Ice Ice Ice Ice Snow Snow (m (m Water Water Water Water Range Range Ecology Ecology Cell vol. vol. Cell vol. Cell

P. nudum (Meunier) Balech 9400AbMn1-1-- D. speculum Ehrenberg 6900c E, N- -111 P. pallidum (Ostenfeld) 13 500 b M, N - - 1 - - Balech Division Chlorophyta P. pellucidum Bergh 51 800c N --1-1 Class Chlorophyceae P. pyriforme subsp. pyriforme 24 000 c - - - 1 - - Carteria sp. 1-1-2 (Paulsen) Balech Chlamidomonas sp. 121- - P. pyriforme subsp. breve 23 300Ab?- ----1 Tetraselmis sp. 1---- (Paulsen) Balech P. subinerme (Paulsen) Loe- 62 500c - 1---1 Class Euglenophyceae 1 blich III Eutreptiella braarudii 7500AbN 1-111 Scrippsiella trochoidea 5900c N 11111 Throndsen (Stein) Loeblich III E. eupharyngea Moestrup & 600AbN 11111 Torodinium robustum Kofoid 4500- - 1-1-1 Norris & Swezy E. gymnastica Throndsen 2000 - N 1 - 1 2 1 Warnowia maculata (Kofoid 15 750------1 E. hirudoidea Butcher 560- N 1---- & Swezy) Lindemann Eutreptia sp. --11- Woloszynkia reticulata 1700- B, N---11 Euglena acus 12000 - - 1 - 1 1 - Thompson Class Prymnesiophyceae Class Prasinophyceae Corimbellus aureus Green 260- Mn1-1-- Halosphaera viridis Schmitz 171 500 c - 1-1-1 Emiliania huxleyi (Lohmann) 400c - 12121 Micromonas pusilla (Butcher) 4tAb?Mn----2 Hay & Mohler Manton & Parke Zigosphaera massilii (Borset- 700- - 1-1-1 Pachysphaera marshalia 100tAb?M 1---1 ti & Cati) Heimdal Parke Phaeocystis pouchetii 35b M 34334 Pterosperma vanhoffenii (Jør- 32 000 - Mn 1 - 1 - - (Hariot) Lagerheim gensen) Ostenfeld Primnesium sp. 1---2 Pyramimonas grossii Parke 50c? - 21122 P. orientalis McFadden, Hill 30tAb?N 1-2-1 Class & Wetherbee marina (Büt- 1100- N 1-1-1 Resultor micron (Throndsen) 4- N ---1- tner) Butcher Moestrup Hilea fusiformis (Schiller) 64tAb?N 1-212 Schiller Cyanobacteria H. marina Butcher 18tAb?N 22311 Anabaenopsis sp. --1-- Leucocryptos marina 480AbMn--1-1 Synechococcus sp. --1-2 (Braarud) Butcher prolonga Butch- 750- - 111-1 Phylum Zoomastigophora er Class Kinetoplastida Teleaulax acuta (Butcher) 340- Mn111-2 Hill subtilis Griessmann 300- N 1-111 Class Chrysophyceae Class Choanofl agellidea Calicomonas gracilis 20- - 222- - Calliacantha natans 32AbMn222- - Calicomonas sp. ----3 (Grøntved) Leadbeater Dinobryon balticum (Schütt) 800AbM 1-223 Parvicorbicula socialis ? 20AbN 34323 Lemmermann (Meunier) Defl andre D. belgica Meunier 600AbM 1-1-1 Monosiga marina Grøntved 100tAb?M 332-2 D. faculiferum (Willén) 260AbMn1-1-1 Pleurasiga reinoldsii Thrond- 6900 tAb? N - - 1 - - Willén sen Ochromonas crenata Klebs 300- B, N11133 Class Raphidophyceae O. marina Lackey 480 Ab N - - 1 - 1 Heterosigma akashiwo 768tAb?b, N1-131 (Hada) Hada Class Dictyochophyceae Dictyocha fi bula Ehrenberg 5500 tAb? M 1 - 1 - -

110 Sea ice algae in the White and Barents seas

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