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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. |
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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 |
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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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Pages |
85-92 |
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Keywords |
Algae; Biomass; Ecology; Ice composition; Antarctica; Bellingshausen Sea; Amundsen Sea; Weddell Sea |
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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. |
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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 @ Dieckmann++1998 |
Serial |
731 |
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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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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 Editor |
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Series Title |
Antarctic Research Series |
Abbreviated Series Title |
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Series Volume |
73 |
Series Issue |
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Edition |
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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 |
Weykam, G.; Thomas, D.N.; Wiencke, C. |
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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 |
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Year |
1997 |
Publication |
Phycologia |
Abbreviated Journal |
Phycologia |
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Volume |
36 |
Issue |
5 |
Pages |
395-405 |
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Keywords |
Winter; Polar waters; Photosynthesis; Antarctic zone; Ice cover; Seaweeds; Light effects; Plant physiology; Growth; Palmariales; Gigartinales; Iridaea cordata; Palmaria decipiens; Ps; Antarctica |
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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. |
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ISSN |
0031-8884 |
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Notes |
Marine |
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no |
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Call Number |
refbase @ admin @ Weykam++1997 |
Serial |
767 |
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Author |
Gomez, I.; Wiencke, C.; Thomas, D.N. |
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Title |
Variations in photosynthetic characteristics of the Antarctic marine brown alga Ascoseira mirabilis in relation to thallus age and size |
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Journal Article |
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Year |
1996 |
Publication |
European Journal of Phycology |
Abbreviated Journal |
Eur J Phycol |
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Volume |
31 |
Issue |
2 |
Pages |
167-172 |
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Keywords |
photosynthesis: thallus: carbon fixation; growth curves; algae; age; Thalli; marine flora; Ascoseira mirabilis; Antarctica |
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Abstract |
Growth, photosynthesis, dark respiration, chlorophyll a (Chl a) content and dry weight were measured in 2- and 3-year-old plants of Ascoseira mirabilis (Ascoseirales), cultivated in the laboratory under changing daylengths which matched the seasonal variations in the Antarctic. Determinations were made in four thallus regions. Growth of A. mirabilis was seasonal, with higher rates in spring. Parameters such as net photosynthesis (P sub(max)), photosynthetic efficiency ( alpha ), both measured on a fresh weight (FW) basis, and dry weight content, showed significant age- and size-dependent variations. In contrast, no variations were observed in dark respiration, initial light-saturating point of photosynthesis (I sub(k)) and Chl a contents. P sub(max) had maximum values close to 16.5 mu mol O sub(2)/g super(1) FW/h in 2-year-old plants, whereas in 3-year-old plants maximum values of 8 mu mol O sub(2)/g FW/h were determined. The alpha -values reached maximum rates of 1.4 and 0.6 mu mol O sub(2)/g FW/h/( mu mol photons/m super(2)/s) in 2- and 3-year-old plants, respectively. Light compensation point (I sub(c)), dry weight ratios and Chl a contents varied significantly along the length of the blade. Maximum dry:fresh weight ratios were observed in the basal region, with values close to 18%. Distal regions of the 3-year-old plants had significantly higher dry weight content than 2-year-old plants (17.5% and 13%, respectively). Chl a concentrations increased towards the middle regions of the thallus to values close to 0.35 mg Chl a/g FW. The results indicate that some morpho-functional processes in A. mirabilis, especially net photosynthesis and photosynthetic efficiency, are governed by age of the plant, thereby reflecting differences in biomass allocation and size. Our data also confirm the previously demonstrated relationship between growth and seasonal physiological activity that allows A. mirabilis to survive under the low light conditions prevailing in the Antarctic. |
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ISSN |
0967-0262 |
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Notes |
growth curves; size; Thalli; marine flora; thallus |
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no |
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Call Number |
refbase @ admin @ Gomez++1996 |
Serial |
737 |
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Author |
Gomez, I.; Thomas, D.N.; Wiencke, C. |
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Title |
Longitudinal profiles of growth, photosynthesis and light independent carbon fixation in the Antarctic brown alga Ascoseira mirabilis |
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Journal Article |
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Year |
1995 |
Publication |
Botanica Marina |
Abbreviated Journal |
Bot Mar |
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Volume |
38 |
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Pages |
157-164 |
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Abstract |
Thallus growth, photoynthetic oxygen evolution and rates of carbon fixation were determinedalong the lamina of the endemic Antarctic brown alga Ascoseira mirabilis (Ascoseirales), grown under simulated Antarctic condtions. The meristem is basally located and forms new blade tiddue under spring-conditions. Light saturated net photosynthesis (P,ax), measures as O? production, was higher in ther intermediate region of the plant (9..8 µmol O? g?¹ fw h?¹). In general, photosynthetic parameters such as dark respiration, gross photosynthesis, photosynthetic efficiency (?) and photosynthetic light compensation (Ic) increased significantly towards the distal region. Carbon-fixation in A. mirabilis also showed thllus-dependent variation. Rates of light and light independent (dark) carbon fixation increased towards the distal regions ranging between 7.6-9.5 and 1.2-2.0 µmol C g?¹ fw h?¹ respectively. The percentage of light independent carbon fixation (in relation to light ¹?C-fixation) also increased from the basal to the distal parts reaching 24% in the distal region of the thallus. he contents of Chl a and Chl c, were close to 0.37 and 0.14 mg g?¹ fw respectively and were notably uniform along the lamina. The results indicate that the formation of the blade by a basal meristem and the increase of light carbon fixation rates from base to the distal regions in A. mirabilis are similar compared with certain Laminariales, especially members of the genus Laminaria. However, light independent carbon fixation is highest in the meristem of Laminaria, opposite to the results obtained here for A. mirabilis |
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Publisher |
de Gruyter |
Place of Publication |
Berlin, New York |
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Call Number |
refbase @ admin @ Gomez++1995 |
Serial |
736 |
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