HPLC analysis of pigments of the symbiotic algae of the coral Goniastrea aspera (Verrill) showed the presence of the chlorophylls a and c2 (chl a and c2) and the carotenoids peridinin, diadinoxanthin, diatoxanthin and β-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 coral/algal 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.
Symbiotic algae · Pigments · Xanthophylls · Coral · Bleaching
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