In situphotosynthetic physiology and chlorophyll-protein biochemistry of two dinoflagellate blooms

Abstract

Photophysiological and biochemical characteristics were defined for a 1981 red-tide of Gonyaulax polyedra along the Santa Barbara coast and a 1980 Exuviella sp. bloom in a marine lagoon. Pigmentation and photosynthesis-irradiance data suggested the G. polyedra population was low-light adapted and nutrient-limited at the time of collection. Analyses of detergent-solubilized chloroplast components indicated that the vast majority of red tide chlorophyll a (Chl a) was organized into four distinct Chl-protein complexes which were biochemically similar to those previously described for a low light clonal isolate of G. polyedra. Differences between laboratory and field populations suggest that Chl c distribution among chromoproteins is regulated by the spectral characteristics of growth irradiance. The Exuviella sp. bloom appeared to be a high-light adapted and nutrient-replete unialgal population at the time of collection. The pigment-protein analysis of Exuviella sp. showed the cellular pigment organization to be also characterized by four major Chl a-containing protein-complexes which were similar to those of other dinoflagellates. Results indicate that the generalized view of chlorophyll organization in dinoflagellates first developed for laboratory clones is applicable to natural red tide populations.