LIPIDS OF SOME CARIBBEAN AND RED-SEA CORALS - TOTAL LIPID, WAX ESTERS, TRIGLYCERIDES AND FATTY-ACIDS

The Caribbean reef-building corals Porites porites (Pallas) and Montas trea annularis (Ellis and Solander) and the Red Sea corals Pocillopora verrucosa (Ellis and Solander), Stylophora pistillata (Esper) and Gon iastrea retiformis (Lamark) were analysed for total lipid, wax ester a nd triglyceride content, and fatty acid composition. M. annularis cont ained about 32% of dry weight as total lipid, whereas much lower value s of between 11 and 17% were recorded for the other four species. It i s concluded that there is greater variation in coral total lipid than hitherto thought. The total lipid contained a substantial proportion o f wax ester (22 to 49%) and triglyceride (18 to 37%). The storage lipi ds (wax esters and triglycerides) accounted for between 6 and 20% of t he dry weight and between 46 and 73% of the total lipid. Variation in lipid content between species could not be attributed to geographical location, but the low values for total lipid in Red Sea corals may in part be due to environmental factors as these samples were collected i n winter. All corals analysed contained high levels of saturated fatty acids, the most abundant fatty acids being 16:0, 18:0 and 18:1n-9. Ma rked differences were observed in polyunsaturated fatty acid (PUFA) co ntent between species, with comparatively low levels of 10 and 11% of fatty acids being recorded in M. annularis and G. retiformis, respecti vely. The values for the other species ranged between 21 and 37%. Fatt y acid composition may vary according to the proportions of fatty acid s obtained from diet, algal photosynthesis and synthesis by the animal tissues.