SS4.07 Lipids/Fatty Acids in Ecological Research
Date: Tuesday, June 11, 2002
Location: Poster Session - VCC
 
GraeveM, Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany, mgraeve@awi-bremerhaven.de
Kattner, G, , Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany, gkattner@awi-bremerhaven.de
Albers, C, , Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany, 
 
BIOSYNTHESIS OF FATTY ACIDS IN COPEPODS: FEEDING EXPERIMENTS WITH 13C ENRICHED PHYTOPLANKTON
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Polar copepods adapt to the pronounced seasonality of food availability and the low temperatures with the accumulation of large lipid deposits. Since copepods are major part of the zooplankton biomass huge amounts of metabolic energy in form of lipids are transferred to higher trophic levels. To characterize carbon flux between phytoplankton and zooplankton and to study transfer and biosynthesis of lipids and individual fatty acids herbivorous calanoid copepods from Arctic and Antarctic were fed with 13C-enriched phytoplankton. The amount of 13C was quantified by gas chromatographic-combustion-IRMS technique. The atom percent values of 13C, accumulated in the copepods, provide detailed information about their lipid biosynthesis. The long-chain fatty acids and alcohols, which are synthesized de novo, were enriched in the 13C isotope showing that they are derived from metabolic precursors. These values are comparable to those of phytoplankton fatty acids, which are incorporated unchanged into the copepod lipids. Major part of the ingested carbon was used for the biosynthesis of wax esters. The isotope studies are an efficient tool to investigate carbon accumulation and turnover of lipids and hence life cycle strategies of zooplankton.