Temporal and Depth Variation of Photoprotective Mycosporine-Like Amino Acids in Soft Coral Species from the Eastern Red Sea Coast

Mycosporine-like amino acids (MAAs) were investigated in two soft coral species collected during summer and winter of 2003 and 2004 at 5, 10, 15, and 20 m depth. Four different MAAs were detected. Palythine was the dominant compound in Sinularia polydac- tyla and Sarcophyton trocheliophorum. The palythine concentration in S. trocheliophorum varied from 44 to 141 µg mg 1 protein in summer compared to 33 to 129 µg mg?1 protein in winter. The corresponding variation in S. polydactyla was 34 to 187 µg mg 1 in summer and 24 to 127 µg mg 1 protein in winter. Both the maxima and minima were higher in summer compared to winter and at all depths. Next to palythine; porphyra-334 was detected in S. trocheliophorum. It was one eigth compared to palythine. The concentration of asterina-330 in S. trocheliophorum was almost negligible. Mycosporine-glycine was not detected at any depth or season indicating that the organism has passed through the initial evolutionary process. Photosynthetically Active Radiation (PAR) was 67% more in summer compared to winter and hence explains the fact that the production of MAAs is more in summer compared to winter indicating that the photosynthetic zone favours the production of MAAs.