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Author |
Thomas, D.N. |
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Title |
Photosynthetic microbes in freezing deserts |
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Journal Article |
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Year |
2005 |
Publication |
Trends in Microbiology |
Abbreviated Journal |
Trends Microbiol |
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Volume |
13 |
Issue |
3 |
Pages |
87-88 |
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Abstract |
Polar deserts are not devoid of life despite the extreme low temperature and scarcity of water. Recently, patterned stone fields – caused by periglacial activity – have been surveyed in the Arctic and Antarctic. It was found that the productivity of the cyanobacteria and algae (hypoliths) that colonise the underside of the stones is strongly related to the pattern of the stones. The hypolith assemblages were in some cases as productive as lichens, bryophytes and plants that resided nearby. |
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Publisher |
Elsevier Science B.V. |
Place of Publication |
Amsterdam |
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Language |
English |
Summary Language |
English |
Original Title |
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ISSN |
0966-842X |
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Call Number |
refbase @ admin @ Thomas2005 |
Serial |
755 |
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Author |
Thomas, D.N.; Dieckmann, G.S. (eds) |
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Title |
Sea ice – an introduction to its physics, chemistry, biology and geology |
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Book Whole |
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Year |
2003 |
Publication |
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Pages |
402 pp |
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Keywords |
Sea Ice |
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Abstract |
Sea ice, which covers up to 7% of the planet's surface, is a major component of the world's oceans, partly driving ocean circulation and global climate patterns. It provides a habitat for a rich diversity of marine organisms, and is a valuable source of information in studies of global climate change and the evolution of present day life forms. Increasingly, sea ice is being used as a proxy for extraterrestrial ice covered systems.
Sea Ice provides a comprehensive review of our current available knowledge of polar pack ice, the study of which is severely constrained by the logistic difficulties of working in such harsh and remote regions of the earth. The book's editors, Drs Thomas and Dieckmann have drawn together an impressive group of international contributing authors, providing a well-edited and integrated volume, which will stand for many years as the standard work on the subject. Contents of the book include details of the growth, microstructure and properties of sea ice, large-scale variations in thickness and characteristics, its primary production, micro-and macrobiology, sea ice as a habitat for birds and mammals, sea ice biogeochemistry, particulate flux, and the distribution and significance of palaeo sea ice. |
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Address |
Thomas: School of Ocean Sciences, University of Wales, Bangor, UK; Dieckmann: Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany |
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Publisher |
Blackwell Science Ltd |
Place of Publication |
Oxford |
Editor |
Thomas, D.N.; Dieckmann, G.S. |
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Language |
English |
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ISBN |
0-632-05808-0 |
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Notes |
40 Illustrations |
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yes |
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Call Number |
refbase @ user @ library-34/436/1 |
Serial |
7 |
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Author |
Gleitz, M.; Thomas, D.N. |
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Title |
Physiological responses of a small Antarctic diatom (Chaetoceros sp.) to simulated environmental constraints associated with sea-ice formation |
Type |
Journal Article |
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Year |
1992 |
Publication |
Marine Ecology Progress Series |
Abbreviated Journal |
Mar Ecol Prog Ser |
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Volume |
88 |
Issue |
2-3 |
Pages |
271-278 |
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Keywords |
plant physiology; abiotic factors; temperature effects; salinity effects; irradiance; sea ice; growth; photosynthesis; Chaetoceros; Psw; Weddell Sea; simulation |
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Abstract |
The physiological responses of a small unicellular Chaetoceros species, isolated from the Weddell Sea, Antarctica, to changes in temperature, salinity and irradiance simulating those that occur during new-ice formation were investigated. The combination of increased salinity, increased quantum irradiance and decreased temperature significantly reduced growth and photosynthetic rates compared to the control, although cellular metabolism was not inhibited. The cells retained the capacity to photoacclimate, which was observed in the variations in cellular chlorophyll a concentrations and carbon allocation patterns. In terms of photosynthesis, a doubling of quantum irradiance apparently compensated for the adverse effects of increased salinity and lowered temperature. It is thus hypothesized that at least some species of the late season phytoplankton population survive incorporation into ice and continue to photosynthesize and grow under the extreme conditions encountered during sea-ice formation. |
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Inter-Research |
Place of Publication |
Oldendorf/Luhe |
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ISSN |
0171-8630 |
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Notes |
Bibliogr.: 38 ref.; Marine |
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no |
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Call Number |
refbase @ admin @ Gleitz+Thomas1992 |
Serial |
735 |
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Author |
Thomas, D.N.; Gleitz, M. |
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Title |
Allocation of photoassimilated carbon into major algal metabolite fractions: Variation between two diatom species isolated from the Weddell Sea (Antarctica) |
Type |
Journal Article |
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Year |
1993 |
Publication |
Polar Biology |
Abbreviated Journal |
Polar Biol |
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Volume |
13 |
Issue |
4 |
Pages |
281-286 |
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Keywords |
carbon fixation; metabolites; biomass; Nitzschia curta; Chaetoceros; Psw; Weddell Sea |
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Abstract |
Distribution of photoassimilated carbon into major metabolite classes differed between two Antarctic diatom species, Nitzschia curta and a small unicellular Chaetoceros sp.. Time course uptake studies (over 54 h) revealed that¹?C allocation appeared to be equilibrated after approximately 8 h at light saturated photosynthesis. During short term dark periods (6 h), polysaccharides as well as low-molecular-weight compounds were catabolised to sustain protein synthesis in the dark, whilst lipid reserves were not mobilised for this process. Experiments with these two species were conducted at 0 and -1.5 degree C, although no difference in the distribution of radiolabel was measured between the two temperatures. It is hypothesised that under near-optimal conditions fast growing species are characterised by a high carbon turnover associated with a rapid flow of newly assimilated carbon into polymeric compound classes. On the other hand, slower growing species (such as N. curta) may store a significant amount of surplus carbon in the low-molecular-weight metabolite fraction. Species specific preferences were observed when comparing the accumulation of radiolabel into the lipid pools. |
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Springer-Verlag |
Place of Publication |
Heidelberg |
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Abbreviated Series Title |
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Series Volume |
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Edition |
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ISSN |
0722-4060 |
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Notes |
Bibliogr.: 48 ref.; Marine |
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no |
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Call Number |
refbase @ admin @ Thomas+Gleitz1993 |
Serial |
760 |
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Author |
Giannelli, V.; Thomas, D.N.; Haas, C.; Kattner, G.; Kennedy, H.; Dieckmann, G.S. |
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Title |
Behaviour of dissolved organic matter and inorganic nutrients during experimental sea-ice formation |
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 |
317-321 |
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Abstract |
It is well established that during sea-ice formation, crystals aggregate into a solid matrix, and dissolved sea-water constituents, including inorganic nutrients, are rejected from the ice matrix. However, the behaviour of dissolved organic matter (DOM) during ice formation and growth has not been studied to date. DOM is the primary energetic substrate for microbial heterotrophic activity in sea water and sea ice, and therefore it is at the base of the trophic fluxes within the microbial food web. The aim of our study was to compare the behaviour of DOM and inorganic nutrients during formation and growth of sea ice. Experiments were conducted in a large indoor ice-tank facility (Hamburg Ship Model Basin, Germany) at -15°C. Three 1 m³ tanks, to which synthetic sea water, nutrients and dissolved organic compounds (diatom-extracted DOM) had been added, were sampled over a period of 5 days during sea-ice formation. Samples were collected throughout the experiment from water underlying the ice, and at the end from the ice as well. Brine was obtained from the ice by centrifuging ice cores. Inorganic nutrients (nitrate and phosphate) were substantially enriched in brine in comparison to water and ice phases, consistent with the processes of ice formation and brine rejection. Dissolved organic carbon (DOC) was also enriched in brine but was more variable and enriched in comparison to a dilution line. No difference in bacteria numbers was observed between water, ice and brine. No bacteria growth was measured, and this therefore had no influence on the measurable DOC levels. We conclude that the incorporation of dissolved organic compounds in newly forming ice is conservative. However, since the proportions of DOC in the brine were partially higher than those of the inorganic nutrients, concentrating effects of DOC in brine might be different compared to salts. |
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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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Edition |
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ISSN |
0260-3055 |
ISBN |
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Notes |
Conference |
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no |
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Call Number |
refbase @ admin @ Giannelli++2001 |
Serial |
732 |
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