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Author Gleitz, M.; Thomas, D.N. url  openurl
  Title Variation in phytoplankton standing stock, chemical composition and physiology during sea-ice formation in the southeastern Weddell Sea, Antarctica Type Journal Article
  Year 1993 Publication Journal of Experimental Marine Biology and Ecology Abbreviated Journal J Exp Mar Biol Ecol  
  Volume 173 Issue 2 Pages 211-230  
  Keywords Antarctic; ecophysiology; ice algae; phytoplankton; primary production; sea-ice formation; biochemical composition; plant physiology; Psw; Weddell Sea; population number; sea ice; algae; standing crop  
  Abstract Changes in physico-chemical conditions, phytoplankton biomass, biochemical composition and primary productivity were investigated during autumnal sea-ice formation in the southeastern Weddell Sea, Antarctica. During sea-ice growth, brine salinities gradually increased with decreasing temperature. Nutrient concentrations in the brine of sea ice older than 2 weeks were lower than calculated from initial surface seawater values. The concomittant accumulation of phytoplankton biomass could not be explained solely by physical enrichment. We suggest that several microalgal species retained the capacity to assimilate nutrients and continued to grow in newly formed sea ice. However, nutrient depletions were moderate, and biochemical analyses did not indicate nutrient stress of algal metabolism. Relative abundance of smaller diatom species increased during ice growth, suggesting that pore space available for colonization in conjunction with physiological acclimation capacity were major factors determining successional patterns in recently formed sea ice. Even though ice algal assemblages apparently sustained the capacity to acclimate to reduced irradiances brought about by ice growth and increasing snow cover, maximum primary production was considerably lower than values usually reported from spring and summer ice communities. Therefore, autumnal primary production in newly formed sea ice may not add greatly to total annual production, but may provide an important food source for ice-associated grazers during the winter period, when phytoplankton biomass in the water column is extremely low.  
  Address  
  Corporate Author Thesis  
  Publisher Elsevier Science B.V. Place of Publication Amsterdam Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-0981 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number (down) refbase @ admin @ Gleitz+Thomas1993 Serial 734  
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Author Gleitz, M.; Thomas, D.N. url  openurl
  Title Physiological responses of a small Antarctic diatom (Chaetoceros sp.) to simulated environmental constraints associated with sea-ice formation Type Journal Article
  Year 1992 Publication Marine Ecology Progress Series Abbreviated Journal Mar Ecol Prog Ser  
  Volume 88 Issue 2-3 Pages 271-278  
  Keywords plant physiology; abiotic factors; temperature effects; salinity effects; irradiance; sea ice; growth; photosynthesis; Chaetoceros; Psw; Weddell Sea; simulation  
  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.  
  Address  
  Corporate Author Thesis  
  Publisher Inter-Research Place of Publication Oldendorf/Luhe Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0171-8630 ISBN Medium  
  Area Expedition Conference  
  Notes Bibliogr.: 38 ref.; Marine Approved no  
  Call Number (down) refbase @ admin @ Gleitz+Thomas1992 Serial 735  
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Author Gleitz, M.; Rutgers v d Loeff, M.; Thomas, D.N.; Dieckmann, G.S.; Millero, F.J. url  openurl
  Title Comparison of summer and winter inorganic carbon, oxygen and nutrient concentrations in Antarctic sea ice brine Type Journal Article
  Year 1995 Publication Marine Chemistry Abbreviated Journal Mar Chem  
  Volume 51 Issue 2 Pages 81-91  
  Keywords dissolved oxygen; inorganic compounds; summer; winter; nutrients (mineral); Antarctic zone; sea ice; brines; carbon; chemical composition; Psw; Weddell Sea; polar zones; polar regions; nutrients  
  Abstract During summer (January 1991) and winter (April 1992) cruises to the southern Weddell Sea (Antarctica), brine samples were collected from first year sea ice and analysed for salinity, temperature, dissolved oxygen and major nutrient concentrations. Additionally, the carbonate system was determined from measurements of pH and total alkalinity. During winter, brine chemical composition was largely determined by seawater concentration in the course of freezing. Brine temperatures ranged from -1.9 to -6.7 °C. Precipitation of calcium carbonate was not observed at the corresponding salinity range of 34 to 108. Removal of carbon from the total inorganic carbon pool (up to 500 µmol Ct kg?¹) was related to reduced nutrient concentrations, indicating the presence of photosynthetically active ice algal assemblages in the winter sea ice. However, nutrient and inorganic carbon concentrations did generally not reach growth limiting levels for phytoplankton. The combined effect of photosynthesis and physical concentration resulted in O? concentrations of up to 650 µmol kg?¹. During summer, brine salinities ranged from 21 to 41 with most values >28, showing that the net effect of freezing and melting on brine chemical composition was generally slight. Opposite to the winter situation, brine chemical composition was strongly influenced by biological activity. Photosynthetic carbon assimilation resulted in a Ct depletion of up to 1200 µmol kg?¹, which was associated with CO? (aq) exhaustion and O? concentrations as high as 933 µmol kg?¹. The concurrent depletion of major nutrients generally corresponded to uptake ratios predicted from phytoplankton biochemical composition. Primary productivity in summer sea ice is apparently sustained until inorganic resources are fully exhausted, resulting in brine chemical compositions that differ profoundly from those of surface waters. This may have important implications for pathways of ice algal carbon acquisition, carbon isotope fractionation as well as for species distribution in the open water phytoplankton.  
  Address  
  Corporate Author Thesis  
  Publisher Elsevier Science B.V. Place of Publication Amsterdam Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-4203 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number (down) refbase @ admin @ Gleitz++1995 Serial 733  
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Author Giannelli, V.; Thomas, D.N.; Haas, C.; Kattner, G.; Kennedy, H.; Dieckmann, G.S. url  openurl
  Title Behaviour of dissolved organic matter and inorganic nutrients during experimental sea-ice formation Type Journal Article
  Year 2001 Publication Annals of Glaciology Abbreviated Journal Ann Glaciol  
  Volume 33 Issue 1 Pages 317-321  
  Keywords  
  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.  
  Address  
  Corporate Author Thesis  
  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,  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0260-3055 ISBN Medium  
  Area Expedition Conference  
  Notes Conference Approved no  
  Call Number (down) refbase @ admin @ Giannelli++2001 Serial 732  
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Author Dieckmann, G.S.; Eicken, H.; Haas, C.; Garrison, D.L.; Gleitz, M.; Lange, M.; Nöthig, E.-M.; Spindler, M.; Sullivan, C.W.; Thomas, D.N.; Weissenberger, J. isbn  openurl
  Title A compilation of data on sea ice algal standing crop from the Bellingshausen, Amundsen and Weddell Seas from 1983 to 1994 Type Book Chapter
  Year 1998 Publication Antarctic sea ice: Biological processes, interactions and variability Abbreviated Journal  
  Volume Issue Pages 85-92  
  Keywords Algae; Biomass; Ecology; Ice composition; Antarctica; Bellingshausen Sea; Amundsen Sea; Weddell Sea  
  Abstract Algal standing stock as chlorophyll a in sea ice was compiled from 448 cores collected during 13 U.S. and German research cruises to Antarctica between 1983 and 1994. The data have a high variability and show no clear relationships with other parameters such as core length. However, seasonal variations in standing stock are discernable. The authors recommend that due to the high variability in the data and inconsistency of sampling methods, the data be used with caution, since they do not represent all sea ice habitats. We provide the data due to the current need for such information for the parameterization of models.  
  Address  
  Corporate Author Thesis  
  Publisher American Geophysical Union Place of Publication Washington, DC Editor Lizotte, M.P.; Arrigo, K.R.  
  Language Summary Language Original Title  
  Series Editor Series Title Antarctic Research Series Abbreviated Series Title  
  Series Volume 73 Series Issue Edition  
  ISSN ISBN 0-87590-901-9 Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number (down) refbase @ admin @ Dieckmann++1998 Serial 731  
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