Lipids and trophodynamics of Antarctic zooplankton

Zooplankton were collected by trawl from the Elephant Island region of the Antarctic Peninsula and from East Antarctica near 63-65°S and 139-150°W. Most zooplankton had low percentages of wax esters (0-8%, as percent of total lipid). High triacylglycerol levels were found in the hyperiid amphipod Themisto gaudichaudii (68%, as percent of total lipid), the krill (Euphausiacea) Euphausia tricantha (44-54% triacylglycerol) and Euphausia frigida (27% triacylglycerol) and the scyphomedusan Periphylla periphylla (42-48% triacylglycerol). Polyunsaturated fatty acids (PUFA) comprised 23-60% of the total fatty acids, with the omega-3 fatty acids eicosapentaenoic acid [20:5(n-3)] and docosahexaenoic acid [22:6(n-3)] being most abundant. P. periphylla was an exception with 12-19% docosapentaenoic acid [22:5 (n-3)] being the major PUFA. The major euphausiid sterols included cholesterol (75-92%, as percent of total sterols) and desmosterol (6-22%). The major sterols of other zooplankton were more diverse and included trans-dehydrocholesterol, 24-methylenecholesterol, brassicasterol and 24-nordehydrocholesterol. The benthic ascidian, Distaplia cylindrica, had 45% stanols, as percent of total sterols, whereas the pelagic ascidian Salpa thompsonii had only 8-11% stanols. Lipid, fatty acid and sterol data are used to examine trophodynamic interactions and provide an ability to distinguish herbivorous and carnivorous diets and determine survival and reproductive strategies. Copyright (C) 1998 Elsevier Science Inc.