Temporal variation in fatty acid composition of Ulothrix zonata (Chlorophyta) from ice and benthic communities of Lake Baikal

Abstract

S. Osipova, L. Dudareva, N. Bondarenko, A. Nasarova, N. Sokolova, L. Obolkina, O. Glyzina and Oleg Timoshkin. 2009. Temporal variation in fatty acid composition of Ulothrix zonata (Chlorophyta) from ice and benthic communities of Lake Baikal. Phycologia 48: 130–135. DOI: 10.2216/08-49Fatty acid (FA) composition of total lipids was compared between populations of the freshwater alga Ulothrix zonata growing in the interstitial water of the ultrapure ice cover of Lake Baikal in early spring (ice population) and on the shallow stony bottom of the lake during the ice-free season (benthic population). FA content was analysed by chromatographic mass spectrometry. Our observations over two years indicated that the FA profiles of both Baikalian ice and benthic populations of U. zonata, as are typical for other green algae, showed a high level of polyunsaturated FAs (50–70% depending on season) related to the adaptation of the alga to low temperature. Rising temperature in the algal habitat entailed a prominent drop in the proportion of monoenoic cis-7-hexadecenoic acid (from 0.8% to 3.5% in 2006). These results favour the hypothesis that monoenoic FAs play a principal role in maintaining the cellular membrane fluidity of U. zonata.