Lipid components of the mediterranean seagrass Posidonia Oceanica

The component fatty acids and alkanes of the seagrass Posidonia oceanica collected on the Mediterranean coasts of France and Greece are reported. Chlorophyllous and non-chlorophyllous parts of the leaves and the rhizomes were examined. Three lipid fractions were isolated, neutral lipids, glycolipids and phospholipids, and their fatty acid composition analysed. The acid 34:0 was found to be associated with neutral lipids. Posidonia oceanica is characterized by the presence of long-chain fatty acids (C 22–C 34) by contrast with those found in marine algae (C 22–C 24). The major fatty acids in the leaves are 16:0, 18:2 n6 and 18:3 n3, and in the rhizomes 16:0, 18:2 n6 and 18:1 n9. Alkanes show a predominance of odd over even numbered carbon chains together with a bimodal distribution; long-chain alkanes > C 20 dominate at C 23 or C 25 for all parts of the seagrass and short-chain alkanes are dominated by C 15 and C 19 for samples from the Mediterranean French coast and by C 17 and C 19 for samples from Greece.