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Author |
Thomas, D.N.; Lara, R.J.; Haas, C.; Schnack-Schiel, S.B.; Dieckmann, G.S.; Kattner, G.; Nöthig, E.-M.; Mizdalski, E. |
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Title |
Biological soup within decaying summer sea ice in the Amundsen Sea, Antarctica |
Type |
Book Chapter |
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Year |
1998 |
Publication |
Antarctic sea ice: Biological processes, interactions and variability |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
161-171 |
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Keywords |
Marine biology; Algae; Ice composition; Pack ice; Decomposition; Ecology; Nutrient cycle; Antarctica; Amundsen Sea |
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Abstract |
In late February 1994, during the ANT XI/3 expedition of R/V Polarstern, ice cores from perennial sea ice were sampled in the Amundsen Sea in areas of dense pack ice. The ice was largely rotten, and a conspicuous feature was the occurrence of thick gaps and voids, often filled with a dark brown slush comprised of loose ice chunks and crystals. These interior ice assemblages were at depths between 1.0 and 1.5 m in 3 to 4 m thick ice floes, and had remarkably rich interior ice algal assemblages (<= 377 µg Chl a L?¹) which were in turn a food source for unusually large numbers of foraminifers (<= 1262 individuals L?¹), the calanoid copepod Stephos longipes (<= 163 individuals L?¹) and harpacticoid copepods (<= 168 individuals L?¹). Analysis of inorganic nutrients (nitrate, phosphate, ammonium, nitrite, and silicate) and dissolved organic carbon (DOC) showed that these were sites of high nutrient supply coupled with high rates of nutrient regeneration. |
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Publisher |
American Geophysical Union |
Place of Publication |
Washington, DC |
Editor |
Lizotte, M.P.; Arrigo, K.R. |
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Original Title |
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Series Title |
Antarctic Research Series |
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Series Volume |
73 |
Series Issue |
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Edition |
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ISSN |
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ISBN |
0-87590-901-9 |
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no |
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Call Number  |
refbase @ admin @ Thomas++1998 |
Serial |
764 |
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Author |
Thomas, D.N.; Kattner, G.; Engbrodt, R.; Giannelli, V.; Kennedy, H.; Haas, C.; Dieckmann, G.S. |
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Title |
Dissolved organic matter in Antarctic sea ice |
Type |
Journal Article |
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Year |
2001 |
Publication |
Annals of Glaciology |
Abbreviated Journal |
Ann Glaciol |
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Volume |
33 |
Issue |
1 |
Pages |
297-303 |
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Keywords |
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Abstract |
It has been hypothesized that there are significant dissolved organic matter (DOM) pools in sea-ice systems, although measurements of DOM in sea ice have only rarely been made. The significance of DOM for ice-based productivity and carbon turnover therefore remains highly speculative. DOM within sea ice from the Amundsen and Bellingshausen Seas, Antarctica, in 1994 and the Weddell Sea, Antarctica, in 1992 and 1997 was investigated. Measurements were made on melted sea-ice sections in 1994 and 1997 and in sea-ice brines in 1992. Dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) concentrations in melted ice cores were up to 1.8 and 0.78 mM, respectively, or 30 and 8 times higher than those in surface water concentrations, respectively. However, when concentrations within the brine channel/pore space were calculated from estimated brine volumes, actual concentrations of DOC in brines were up to 23.3 mM and DON up to 2.2 mM, although mean values were 1.8 and 0.15 mM, respectively. There were higher concentrations of DOM in warm, porous summer second-year sea ice compared with colder autumn first-year ice, consistent with the different biological activity supported within the various ice types. However, in general there was poor correlation between DOC and DON with algal biomass and numbers of bacteria within the ice. The mean DOC/DON ratio was 11, although again values were highly variable, ranging from 3 to highly carbon-enriched samples of 95. Measurements made on a limited dataset showed that carbohydrates constitute on average 35% of the DOC pool, with highly variable contributions of 1–99%. |
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Publisher |
International Glaciological Society |
Place of Publication |
Cambridge |
Editor |
Intl. Symp. on Sea Ice and its Interaction with the Ocean, A. and B., Fairbanks, Alaska(USA), 19-23 Jun 2000, |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0260-3055 |
ISBN |
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Conference |
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no |
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Call Number |
refbase @ admin @ Thomas++2001 |
Serial |
761 |
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Author |
Thomas, D.N.; Kennedy, H.; Kattner, G.; Gerdes, D.; Gough, C.; Dieckmann, G.S. |
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Title |
Biogeochemistry of platelet ice: its influence on particle flux under fast ice in the Weddell Sea, Antarctica |
Type |
Journal Article |
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Year |
2001 |
Publication |
Polar Biology |
Abbreviated Journal |
Polar Biol |
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Volume |
24 |
Issue |
7 |
Pages |
486-496 |
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Keywords |
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Abstract |
An array of four sediment traps and one current meter was deployed under a well-developed platelet layer for 15 days in the Drescher Inlet in the Riiser Larsen ice shelf, in February 1998. Traps were deployed at 10 m (just under the platelet layer), 112 m (above the thermocline), 230 m (below thermocline) and 360 m (close to sea floor). There was a substantial flux of particulate organic material out of the platelet layer, although higher amounts were collected in the traps either side of the thermocline. Material collected was predominantly composed of faecal pellets containing diatom species growing within the platelet layer. The size classes of these pellets suggest they derive from protists grazing rather than from larger metazoans. Sediment trap material was analysed for particulate organic carbon/nitrogen/phosphorus (POC/PON/POP) and ?¹³CPOC (carbon isotopic composition of POC). These were compared with organic matter in the overlying platelet layer and the water column. In turn, the biogeochemistry of the platelet layer and water column was investigated and the organic matter characteristics related to inorganic nutrients (nitrate, nitrite, ammonium, silicate, phosphate), dissolved organic carbon/nitrogen (DOC/DON), pH, dissolved inorganic carbon (DIC), oxygen and ?¹³CDIC (carbon isotopic composition dissolved inorganic carbon). |
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Publisher |
Springer-Verlag |
Place of Publication |
Heidelberg |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0722-4060 |
ISBN |
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no |
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Call Number |
refbase @ admin @ Thomas++2001_2 |
Serial |
762 |
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Author |
Thomas, D.N.; Dieckmann, G.S. |
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Title |
Biogeochemistry of Antarctic sea ice |
Type |
Journal Article |
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Year |
2002 |
Publication |
Oceanography and Marine Biology: An Annual Review |
Abbreviated Journal |
Oceanogr Mar Biol Annu Rev |
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Volume |
40 |
Issue |
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Pages |
143-169 |
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Keywords |
Sea ice; Biogeochemistry; Nutrients (mineral); Dissolved gases; Dissolved organic matter; Ps; Antarctic Ocean |
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Abstract |
Antarctic sea ice at its maximum extent in winter covers 40% of the Southern Ocean in a frozen layer, on average, 1 m thick. Sea ice is not solid, rather it is an ice crystal matrix permeated by a labyrinth of brine filled channels and pores in which life thrives. Organisms are constrained by a set of physicochemical factors quite unlike anything they encounter in the plankton from where they are recruited. Because sea ice is increasingly viewed as a suitable proxy for life in previous periods of the Earth's history, and even for astrobiology, it is pertinent that the physicochemical constraints acting upon sea-ice biology are better understood. The, largely microbial, network that develops in the ice itself imparts a unique chemistry that influences the nature and chemical composition of biogenic material released from the ice. This chemistry can result in the export of material to the sediments with distinctive chemical signatures that are useful tools for reconstructing past sea-ice cover of the oceans. This review synthesises information on inorganic nutrient, dissolved organic matter and dissolved gases from a variety of Antarctic ice habitats. |
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Publisher |
Taylor & Francis |
Place of Publication |
London |
Editor |
Gibson, R.N.; Barnes, M.; Atkinson, R.J.A. |
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Original Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0415254620 |
ISBN |
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Notes |
Review; Marine |
Approved |
no |
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Call Number |
refbase @ admin @ Thomas+Dieckmann2002 |
Serial |
758 |
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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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Publisher |
American Association for the Advancement of Science |
Place of Publication |
Washington, DC |
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Summary Language |
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Original Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0036-8075 |
ISBN |
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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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