Chemical composition of corals in Saudi Red Sea Coast

Three species of corals Stylophora pistillata, Lobophyllia corymbosa and Echinopora gemmacea were collected from Sharm Obhur to study their chemical composition. This information was important in the investigation of their metabolic pathways and their mode of feeding. The concentrations of amino acids in these species were 9.37, 21.35 and 3.09 mg.g(-1) dry weight of coral respectively. Plant pigments were highest in E. gemmacea followed by S. pistillata and then by L. corymbosa. Lipid concentrations in S. pistillata, L. corymbosa and E. gemmacea were 1.90, 8.58 and 1.32 mg.g(-1) of total coral respectively. The fatty acid methyl esters were analyzed in these species and the most abundant saturated acids were 16:0 and 18:0, while unsaturated acids included 16:1, 18:1 and 19:3. The carbohydrate concentrations were 559, 425 and 859 mu g.g(-1) of total coral dry weight. Residual matter was 42.5, 32.8 and 41.39 per cent by weight of total coral. These data suggest a greater reliance on autotrophic feeding in E. gemmacea and S, pistillata and mostly heterotrophic feeding in L. corymbosa. (C) Elsevier, Paris.