Abstract

SUNAGAWA, S; CORTES, J; JIMENEZ, C  and  LARA, R. Variation in cell densities and pigment concentrations of symbiotic dinoflagellates in the coral Pavona clavus in the eastern Pacific (Costa Rica). Cienc. mar [online]. 2008, vol.34, n.2, pp.113-123. ISSN 0185-3880.

The density and chlorophyll concentrations of symbiotic dinoflagellates (zooxanthellae) in the eastern Pacific coral Pavona clavus were monitored over the transitional period from rainy to dry season in a seasonal upwelling region and in a non-upwelling region of the Costa Rican Pacific coast. The temporal patterns of algal chlorophyll a and c concentrations displayed a negative correlation with light availability, irrespective of the study site, while the cell densities followed a dissimilar pattern. Correlations with water temperature, rainfall, and salinity indicated that a decrease in the density of zooxanthellae was probably associated with a decrease in water temperature due to seasonal cooling in the upwelling region and the negative effects of terrestrial runoff during the rainy season in the non-upwelling region (i.e., low salinity and high turbidity). The results of this study suggest that correlations between zooxanthellae density and water temperature (negative), light intensity (negative), or nutrients (positive), as proposed in previous studies, might not be applicable for regions where seasonal upwelling and strong influence of terrestrial runoff represent important features.

Keywords : Costa Rica; Pavona clavus; terrestrial runoff; upwelling; zooxanthellae.

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