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Author |
Schnack-Schiel, S.B.; Dieckmann, G.S.; Gradinger, R.; Melnikov, I.A.; Spindler, M.; Thomas, D.N. |
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Title |
Meiofauna in sea ice of the Weddell Sea (Antarctica) |
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Journal Article |
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Year |
2001 |
Publication |
Polar Biology |
Abbreviated Journal |
Polar Biol |
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Volume |
24 |
Issue |
10 |
Pages |
724-728 |
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Keywords |
Sea ice biota; Foraminifera; Antarctic sea ice; Sea ice; Meiofauna; Community composition; Meiobenthos; Antarctic zone; Juveniles; Psw; Weddell Sea; Antarctica |
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Abstract |
Sea-ice meiofauna was studied during various cruises to the Weddell Sea. Foraminifers dominate (75%) the sea-ice community in terms of numerical abundance while turbellarians dominate (45%) in terms of biomass. Distribution of organisms is patchy and varies considerably between cruises but also between sampling sites within one cruise. The bulk of the meiofauna is concentrated in the lowest parts of the sea ice, especially during winter and autumn. However, in porous summer sea ice, sympagic organisms also occur in high densities in upper and intermediate layers of sea ice. Proto- and metazoans associated with Antarctic sea ice include organisms actually living in sea ice, as well as those on the underside of floes and in the underlying water. The sea-ice habitat serves as a feeding ground, as well as an important nursery for juveniles, providing energy-rich food resources. The ice also constitutes a shelter from predators. |
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Springer |
Place of Publication |
Heidelberg |
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0722-4060 |
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Call Number |
refbase @ admin @ Schnack-Schiel++2001 |
Serial |
751 |
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Author |
Schnack-Schiel, S.B.; Dieckmann, G.S.; Kattner, G.; Thomas, D.N. |
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Title |
Copepods in summer platelet ice in the eastern Weddell Sea, Antarctica |
Type |
Journal Article |
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Year |
2004 |
Publication |
Polar Biology |
Abbreviated Journal |
Polar Biol |
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Volume |
27 |
Issue |
8 |
Pages |
502-506 |
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Abstract |
Copepods in platelet-ice layers underlying fast ice and in the water column below were studied at Drescher Inlet, eastern Weddell Sea in February 1998. Three copepod species were found: Drescheriella glacialis and Paralabidocera antarctica occurred in platelet-ice layers, while Stephos longipes was only present in the water column. The distribution of all species varied considerably between station and depth. D. glacialis dominated the platelet-ice community and occurred at all five platelet-ice sampling sites, except one, with numbers of up to 26 ind. l?¹. In contrast, P. antarctica was only found in low numbers (up to 2 ind. l?¹) at one site. The total copepod abundance in the platelet ice was not associated with algal biomass, although it was strongly correlated with high ammonium concentrations (up to 9 µM) in the interstitial water between the platelets. This is the first indirect evidence to support the hypothesis that zooplankton excretion can partly account for the high ammonium values often found in platelet-ice layers. |
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Springer-Verlag |
Place of Publication |
Heidelberg |
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0722-4060 |
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Call Number |
refbase @ admin @ Schnack-Schiel++2004 |
Serial |
752 |
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Schnack-Schiel, S.B.; Thomas, D.N.; Haas, C.; Dieckmann, G.S.; Alheit, R. |
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Title |
The occurrence of the copepods Stephos longipes (Calanoida) and Drescheriella glacialis (Harpacticoida) in summer sea ice in the Weddell Sea, Antarctica |
Type |
Journal Article |
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Year |
2001 |
Publication |
Antarctic Science |
Abbreviated Journal |
Antarctic Sci |
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Volume |
13 |
Issue |
2 |
Pages |
150-157 |
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Keywords |
copepods; Drescheriella glacialis; sea ice; seasonality; Stephos longipes |
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Abstract |
In January to March 1997, a RV Polarstern cruise that transected the Weddell Sea resulted in samples being taken in thick pack ice in the south-eastern Weddell Sea and then along the marginal ice edge towards the Antarctic Peninsula. Several ice types were thus sampled over a wide geographic area during late summer/early autumn. Common features of the first warm period was the occurrence of surface ponds, and that many floes had quasi-continuous horizontal gaps, underlying a layer of ice and metamorphic snow. With the onset of cold air temperatures in late February the gaps rapidly refroze. The calanoid copepod Stephos longipes occurred in all habitats encountered and showed highest numbers in the surface ice in summer, in the gap water during both seasons and in the refrozen gap water in autumn. Nauplii outnumbered copepodids in the surface ice and refrozen gap water, while in the gap water copepodids, mainly stages CI-CIII in summer and CII-CIV in autumn, comprised about 70% of the total population. The harpacticoid species Drescheriella glacialis did not occur in all habitats and was missing in surface ponds and new ice. Nauplii of D. glacialis were rarely found in gapwater, but predominated in the refrozen gaps. |
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ISSN |
0954-1020 |
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no |
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Call Number |
refbase @ admin @ Schnack-Schiel++2001_2 |
Serial |
753 |
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Author |
Thomas, D.N.; Baumann, M.E.M.; Gleitz, M. |
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Title |
Efficiency of carbon assimilation and photoacclimation in a small unicellular Chaetoceros species from the Weddell Sea (Antarctica): Influence of temperature and irradiance |
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Journal Article |
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Year |
1992 |
Publication |
Journal of Experimental Marine Biology and Ecology |
Abbreviated Journal |
J Exp Mar Biol Ecol |
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Volume |
157 |
Issue |
2 |
Pages |
195-209 |
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Keywords |
photosynthesis; Psw; Weddell Sea; Chaetoceros; temperature effects; irradiance; light effects; acclimation; respiration; carbon fixation; low temperature; polar waters; Antarctica; water temperature |
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Abstract |
It is well established that Antarctic phytoplankton and sea-ice algae are able to thrive at low temperatures and it has been proposed that a reduction in respiration may be important in enabling them to do this. This possibility was studied in an Antarctic clone of a small unicellular Chaetoceros species isolated from the Weddell Sea (Antarctica), using comparative measurements of C assimilation during long- and short-term incubation series over a range of temperatures (-1.5 to 4 °C) at two irradiances (5 and 55 µmol m?²/s). Even though doubling times varied considerably, the total amount of C assimilated per cell per generation time was similar at each of the temperature and light conditions. However, over one cell cycle, significant respiratory C losses were determined by divergences in C assimilation patterns between cumulative and long-term incubations at both light intensities at 0 and 4 °C. At -1.5 °C, insignificant C losses were recorded. No significant extracellular release of dissolved organic material (DOC) was observed. |
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Publisher |
Elsevier Science B.V. |
Place of Publication |
Amsterdam |
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ISSN |
0022-0981 |
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no |
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Call Number |
refbase @ admin @ Thomas++1992 |
Serial |
757 |
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Author |
Thomas, D.N.; Dieckmann, G.S. |
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Title |
Antarctic sea ice – a habitat for extremophiles |
Type |
Journal Article |
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Year |
2002 |
Publication |
Science |
Abbreviated Journal |
Science |
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Volume |
295 |
Issue |
5555 |
Pages |
641-644 |
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Keywords |
Microorganisms; Sea ice; Ecosystems; Polar zones; Antarctic zone; Epontic organisms; Sea ice ecology; Antarctic sea ice; Marine microorganisms; Marine ecosystems; Bacteria; Algae; Psychrophilic bacteria; extremophiles; Ps; Antarctica |
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Abstract |
The pack ice of Earth's polar oceans appears to be frozen white desert, devoid of life. However, beneath the snow lies a unique habitat for a group of bacteria and microscopic plants and animals that are encased in an ice matrix at low temperatures and light levels, with the only liquid being pockets of concentrated brines. Survival in these conditions requires a complex suite of physiological and metabolic adaptations, but sea-ice organisms thrive in the ice, and their prolific growth ensures they play a fundamental role in polar ecosystems. Apart from their ecological importance, the bacterial and algae species found in sea ice have become the focus for novel biotechnology, as well as being considered proxies for possible life forms on ice- covered extraterrestrial bodies. |
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American Association for the Advancement of Science |
Place of Publication |
Washington, DC |
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0036-8075 |
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Notes |
Review |
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no |
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Call Number |
refbase @ admin @ Thomas+Dieckmann2002_2 |
Serial |
759 |
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