BIOCHEMICAL-COMPOSITION OF ANTARCTIC ZOOPLANKTON FROM THE INDIAN-OCEAN SECTOR

Zooplankton samples were analysed for faunal composition, organic carb on, protein, carbohydrate and lipid content. Total zooplankton biomass (as displacement volume) varied from 0.032 to 0.500 ml.m(-3) (($) ove r bar x = 0.23 +/- 0.14) in upper 200 m with significant differences b etween the Antarctic and the sub-Antarctic waters. Calanoid copepods w ere numerically the predominant group comprising greater than or equal to 80% of total counts, whereas, euphausiid Euphausia superba was abu ndant in samples collected south of lat. 55 degrees S. Organic carbon concentrations ranged from 0.83 to 13.04 mgC.m(-3) (($) over bar x = 5 .91 +/- 3.59). Lipid was the principal biochemical component, varying between 11.08 to 27.65% (($) over bar x = 21.04 +/- 4.39). Protein con tent showed large variations and ranged between 8.02 and 29.9% (($) ov er bar x = 19.57 +/- 6.25). Values for carbohydrate content varied fro m 11.01 to 27.65% (($) over bar x = 19.62 +/- 4.80). Higher accumulati on of lipids in Antarctic zooplankton during phytoplankton blooms (aus tral summer) could be an adaptative phenomenon, and may function as me tabolic reserve and insulation layer.