LIPIDS AND FATTY-ACIDS IN ICE ALGAE AND PHYTOPLANKTON FROM THE MARGINAL ICE-ZONE IN THE BARENTS SEA

Samples of ice algae from the Marginal Ice Zone in the Barents Sea cou ld be divided into two categories: one dominated by assemblages of Mel osira arctica, and the other dominated by Nitzschia frigida and associ ated diatoms. Total lipid from the Melosira assemblages consisted of a pproximately equal amounts of polar lipids and triacylglycerols. Total lipid from the Nitzschia assemblages contained more triacylglycerols than polar lipids. Total lipid from the Melosira assemblages had highe r percentages of C16 PUFA, especially 16:4(n-1) and 20:5(n-3), than th at from the Nitzschia assemblages, this reflecting the higher percenta ges of both C16 PUFA and 20,5(n-3) in polar lipids than in triacylglyc erols. Phytoplankton from the pelagic zone were richer in flagellates and contained less C16 PUFA and 20:5(n-3) but more C18 PUFA and 22:6(n -3). The dominance of diatoms in the ice-algae assemblages in the Marg inal Ice Zone and their high nutritional value as a source of 20:5(n-3 ) for higher trophic levels are emphasised.