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Author Mock, T.; Dieckmann, G.S.; Haas, C.; Krell, A.; Tison, J.-L.; Belem, A.L.; Papadimitriou, S.; Thomas, D.N. url  openurl
  Title Micro-optodes in sea ice: a new approach to investigate oxygen dynamics during sea ice formation Type Journal Article
  Year 2002 Publication Aquatic Microbial Ecology Abbreviated Journal Aquat Microb Ecol  
  Volume 29 Issue 3 Pages 297-306  
  Keywords (down) Fragilariopsis cylindrus; Oxygen; Methods; Micro-optodes; Sea ice; Biogeochemistry; Diatoms; Algae; Chlorophyll; Photosynthesis; Salinity effects; Sea water; Marine ecosystems; Chlorophylls; Dissolved oxygen; Gases; Epontic environment; Electrodes; Sensors; Brines; Ice-water interface; Ice formation; Bacillariophyceae  
  Abstract Oxygen micro-optodes were used to measure oxygen dynamics directly within the microstructure of sea ice by freezing the sensors into the ice during its formation. The experiment was conducted in a 4 m³ mesocosm filled with artificial seawater and inoculated with a unialgal culture of the common Antarctic ice diatom Fragilariopsis cylindrus (Bacillariophyceae) to a final chlorophyll a (chl a) concentration of 11 µg 1?¹. Ice growth was initiated 7 d after inoculation by reducing the air temperature to -10 plus or minus 2 degree C and terminated 17 d later. The final ice thickness was 27 cm. One optode was frozen into grease ice and 2 others into the skeletal layer of the growing ice sheet. Increasing oxygen concentrations during ice crystal formation at the water surface and the ice-water interface revealed a strong inclusion of oxygen, which was either physically trapped and/or the result of photosynthesising diatoms. The major portion of oxygen was present as gas bubbles due to super-saturation as a result of increasing salinity and oxygen production by diatoms. An increase in salinity due to a concurrent decrease in ice temperatures during subsequent sea ice development reduced the maximum concentration of dissolved oxygen within brine. Thus, dissolved oxygen concentrations decreased over time, whereas gaseous oxygen was released to the atmosphere and seawater. The sensors are a significant advance on more conventional microelectrodes, because the recordings can be temperature and salinity compensated in order to obtain precise measurements of oxygen dynamics with regard to total (dissolved and gaseous) and dissolved oxygen in sea ice. Optodes do not consume oxygen during measuremnet over a long period under extreme conditions, which is another advantage for long-term deployment in the field.  
  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 0948-3055 ISBN Medium  
  Area Expedition Conference  
  Notes Marine Approved no  
  Call Number refbase @ admin @ Mock++2002 Serial 749  
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Author Thomas, D.N.; Dieckmann, G.S. (eds) url  isbn
openurl 
  Title Sea ice – an introduction to its physics, chemistry, biology and geology Type Book Whole
  Year 2003 Publication Abbreviated Journal  
  Volume Issue Pages  
  Keywords (down) zoology; sea ice  
  Abstract Sea ice, which covers up to 7% of the planets surface, is a major component of the worlds oceans, partly driving ocean circulation and global climate patterns...  
  Address  
  Corporate Author Thesis  
  Publisher Blackwell Science Ltd Place of Publication Oxford Editor Thomas, D.N.; Dieckmann, G.S.  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN 0-632-05808-0 Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number refbase @ user @ Thomas+Dieckmann2003 Serial 845  
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Author Thomas, D.N.; Dieckmann, G.S. (eds) url  isbn
openurl 
  Title Sea ice – an introduction to its physics, chemistry, biology and geology Type Book Whole
  Year 2003 Publication Abbreviated Journal  
  Volume Issue Pages  
  Keywords (down) zoology; sea ice  
  Abstract Sea ice, which covers up to 7% of the planets surface, is a major component of the worlds oceans, partly driving ocean circulation and global climate patterns...  
  Address  
  Corporate Author Thesis  
  Publisher Blackwell Science Ltd Place of Publication Oxford Editor Thomas, D.N.; Dieckmann, G.S.  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN 0-632-05808-0 Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number refbase @ user @ Thomas+Dieckmann2003 Serial 849  
Permanent link to this record
 

 
Author Thomas, D.N.; Dieckmann, G.S. (eds) url  isbn
openurl 
  Title Sea ice – an introduction to its physics, chemistry, biology and geology Type Book Whole
  Year 2003 Publication Abbreviated Journal  
  Volume Issue Pages  
  Keywords (down) zoology; sea ice  
  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.  
  Address  
  Corporate Author Thesis  
  Publisher Blackwell Science Ltd Place of Publication Oxford Editor Thomas, D.N.; Dieckmann, G.S.  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN 0-632-05808-0 Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number refbase @ admin @ Thomas+Dieckmann2003 Serial 15290  
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Author Weykam, G.; Thomas, D.N.; Wiencke, C. openurl 
  Title Growth and photosynthesis of the Antarctic red algae Palmaria decipiens (Palmariales) and Iridaea cordata (Gigartinales) during and following extended periods of darkness Type Journal Article
  Year 1997 Publication Phycologia Abbreviated Journal Phycologia  
  Volume 36 Issue 5 Pages 395-405  
  Keywords (down) Winter; Polar waters; Photosynthesis; Antarctic zone; Ice cover; Seaweeds; Light effects; Plant physiology; Growth; Palmariales; Gigartinales; Iridaea cordata; Palmaria decipiens; Ps; Antarctica  
  Abstract Physiological and developmental responses during and following long-term exposure to darkness were investigated in the Antarctic red algae Palmaria decipiens and Iridaea cordata. Thalli were kept in darkness for a period of 6 mo, simulating winter sea ice cover. Subsequently, they were grown illuminated under seasonally fluctuating Antarctic daylengths. During darkness, P. decipiens, an Antarctic endemic, rapidly lost its ability to photosynthesize although chlorophyll a content remained fairly constant. The amount of floridean starch decreased gradually in the dark, with a sudden drop simultaneous with the development of new blades. After reexposure to light there was a rapid increase in photosynthetic oxygen production, whereas the rate of carbon assimilation increased more slowly, resulting in high apparent photosynthetic quotients. The increase in growth rate showed a close relation to carbon assimilation, suggesting that carbon is utilized first for growth, then for floridean starch accumulation. In contrast to P. decipiens, the photosynthetic rate of the Antarctic cold-temperate I. cordata was still about half of the initial rate after a dark period of 6 mo, i.e. the alga maintained functionality of its photosynthetic apparatus during winter. After reexposure to light there was a continuous increase in specific growth rate due to increasing photosynthetic activity. Iridaea cordata also accumulated floridean starch during summer, although in smaller amounts than P. decipiens. Together with the ability to photosynthesize, starch accumulation facilitates survival during extended dark periods in winter. The early development of blade initials and the rapid increase in photosynthetic capability after illumination may permit P. decipiens to use the period of high water transparency optimally in Antarctic spring. Iridaea cordata seems better able to survive prolonged dark periods in areas with less predictable light conditions. Both physiological patterns are well suited to the highly seasonal light conditions in Antarctica.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-8884 ISBN Medium  
  Area Expedition Conference  
  Notes Marine Approved no  
  Call Number refbase @ admin @ Weykam++1997 Serial 767  
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