The contribution of different food sources in the food web of a shallow-water hydrothermal ecosystem was estimated using fatty acids as markers. The markers were selected based on the results of analyzing the fatty acid composition of potential food sources in Kraternaya Right, Yankich Island, Kurile Islands. Most animals had markers characteristic of diatoms: the 16:0/16:1m? ratio close to 1 and a high 20:503 content. We assume that the bivalves Macoma calcared and Macoma lukini, polychaetes Amphitrite cirrata and Pectinaria hyperborea, and holothurians Eupentacta pseudoquinquesemita and Psolus sp. feed mainly on diatoms. Fatty a c~d s specific to bacteria -branched, odd and 18:lw7 -were found in considerable amounts in the bivalve Ax~nopsida orbiculata, as well as in E pseudoquinquesernita, Psolus sp and P. hyperborea; hence we concluded that there was a substantial bacterial input into the food of these species. A high concentrat~on of C,, and PUFAs (polyunsaturated fatty acids), suggested to be an indicator of brown algae, was detected merely in the gastropod Littorina kurila. Although bactena are more important as a food source in Kraternaya Bight than In typical coastal ecosystems, the major food source for animals here is photosynthetic organisms, rather than chernosynthetic symbionts as is the case with deep-sea hydrothermal vents.

Fourteen reef-building coral species of Anthozoa and Hydrozoa classes, collected in various regions of the Indo-Pacific, were analyzed for fatty acid composition by gas-liquid chromatography. Total lipids of the corals had the same set of fatty acids. The main fatty acids were 16:0, 18:0, 18:l(n-g), 20:4(n-6), 20:5(n-3) and 22:6(n-3), but some coral families had significant levels of characteristic fatty acids. Poc~lloporidae -20:3(n-6), Acroporidae -18:3(n-6), 18:4(n-3) and 22:4(n-6); Poritidae -18.3(n-61, Milleporidae -22:4(n-6), 22:5(n-6) and 22:6(n-3). Related species of Pocilloporidae from Vietnam and Seychelles differed greatly in their content of saturated a c~d s -50 to 60 D/a and 30 %, respectively. As shown for Stylophora pistillata, the depth of the habitat affects the degree of fatty acid unsaturation and (n-3)/(n-6) ratio of neutral lipids, but does not affect phospholipid fatty acids. A possible role of A5-and A4-desaturases in determining fatty acid pool formation in reefbuilding corals is discussed with reference to their nutritional characteristics.

Пленарные доклады 1Казанский институт биохимии и биофизики -обособленное структурное подразделение ФИЦ КазНЦ РАН, Казань, Россия 2Казанский (Приволжский) федеральный университет, Казань, Россия, 3Федеральное государственное бюджетное учреждение науки Институт биохимии и физиологии растений и микроорганизмов РАН, Саратов, Россия, 4Институт органической и физической химии им. А.Е. Арбузова -обособленное структурное подразделение ФИЦ КазНЦ РАН, Казань, Россия