Fluctuations in algal chlorophyll and carotenoid pigments during solar bleaching in the coral Goniastrea aspera at Phuket, Thailand

HPLC analysis of pigments of the symbiotic algae of the coral Goniastl-ea aspera (Verrill) showed the presence of the chlorophylls a and c2 (chl a and c,) and the carotenoids pendlnin, diadinoxanthin, diatoxanthin and p-carotene. Increased production of diatoxanthin was seen In algae extracted from the western surfaces of corals, exposed to high levels of solar radiation, during a solar bleaching event. In addition, an increase in the ratio of diatoxanthin to the total xanthophyll pool was observed in bleached tissues. together with a progressive increase in the total xanthophyll pool (relative to total chlorophyll levels) over the bleaching period. These results support a potential photoprotective function for xanthophylls in the coraValga1 symbiosis. Chlorophyll breakdown products, phaeophytin a and pyrophaeophytin a, were recognised in considerable quantities only in bleached tissues. computation of a simple chlorophyll budget showed that 45% of chl a was lost in partially bleached tissues and approximately 62 % in fully bleached tissues, indicating a very rapid photodegradation of chlorophyll 24 h after exposure to high irradiance.