Comparative analysis of the fatty acid composition of deep-water Baikal amphipods

In this report, we have compared the fatty acid composition of the endemic Lake Baikal amphipods Ommatogammarus albinus (Dybowsky, 1874) and Parapallasea lagowskii (Dybowsky, 1874). Specimens were sampled using the deep-water manned submersible "Mir" at the oil-methane seeps of Cape Gorevoy Utes and at a hydrothermal vent in Frolikha Bay. High levels of monounsaturated fatty acids and relatively low levels of saturated and polyunsaturated fatty acids were detected in the studied amphipods, with oleic and palmitic acid representing the main fatty acid components. The habitat of the amphipods exerted a profound effect on their fatty acid profile: the amphipods of Gorevoy Utes contained higher levels of linolenic 18:3n3 and arachidonic 20:4n6 acids, while the amphipods of Frolikha Bay contained higher levels of eicosapentaenoic 20:5n3 and docosahexaenoic 22:6n3 acid. Based on these findings, we suggest that the amphipods' diet in different areas of Lake Baikal determines their fatty acid composition.