CONCENTRATION OF FULVIC-ACID IN THE GROWTH BANDS OF HERMATYPIC CORALS IN RELATION TO LOCAL PRECIPITATION

Coral growth rate and the concentrations of fulvic acid in the growth bands of the hermatypic coral Porites lutea Edwards & Haime and Favia maxima Veron were investigated in samples taken from 1986 to 1988 in the waters of southern Taiwan (22-degrees-05' approximately 36'N, 120-degrees-24' approximately 50'E). These were analyzed against the local annual precipitation, the locality of the sampling sites, the construction activity on nearby land and coral species. The results showed that the annual growth rate of P. lutea was 1.08 +/- 0.12 cm while F. maxima was 0.83 +/- 0.09 cm. The amount of fulvic acid incorporated in the growth band was positively correlated with the local annual precipitation. However, the correlation coefficient varied from as high as 0.9519 to as low as 0.0921 due to different topographies of the sampling sites, dilution factors from the ocean and construction activities along the coast. F. maxima was found to be more sensitive than P. lutea in terms of fulvic acid uptake from the surrounding waters. The study of fluorescence in the skeleton of hermatypic corals is a reasonable approach to biomonitor the environment after consideration of local factors.