Polar lipid and fatty acid compositions of 26 species of marine macrophytes collected in the Yellow Sea during winter were determined. Each division of seaweeds and seagrasses have distinguishing lipid and fatty acid profiles which have a chemotaxonomic value for marine plants. Algal habitat conditions affect quantitative characteristics of the fatty acids but its influence was not the same for different species. The content of polyunsaturated fatty acids in Chinese algae, in comparison with the same or related species from other regions, was found to be noticeably higher for most of the algal species examined. Members of the genera Rhodomela, Gracilaria, Sargassum, Ulva, Enteromorpha (except E. linza) and Zostera had the same ratios of the principal fatty acids as those for related species from other regions. The draining period during low tides affected lipid content and ratio of polyunsaturated fatty acids in algae but it did not influence the polar lipid and fatty acid profiles.

Total lipid content and fatty acid composition of total, polar and neutral lipids were investigated in the lancelet Branchiostoma belcheri tsingtaoense. The total lipid content was 1.70% on wet weight in female animals, 1.37% in males and 3.94% in eggs. Most parts of the lipids were phospholipids. Main fatty acids were 16:0, 16:1 (n-7), 18:0, 18:l(n-7), 18:4 (n-3), 20:5 (n-3), 22:5 (n-3) and 22:6 (n-3). Neutral lipids of male and female animals and eggs contained 4.3%, 11.1% and 13.8% octadecatetraenoic acid, respectively. High levels of odd and branched-chain acids (up to 10% of total content), both in neutral and polar lipids suggest a significant role of detritus and bacteria in lancelet's nutrition.