Physiological variability within a Peridinium gatunense (Dinoflagellate) population during its patchy bloom in Lake Kinneret

摘要

Patchy blooms of dinoflagellates are a universal phenomenon frequently observed in marine and freshwater environments. In Lake Kinneret (Sea of Galilee), Israel, the spring bloom of the dinoflagellate Peridinium gatunense is characterized by a spatial heterogeneity, concomitant with a diurnal vertical migration of the population (Pollingher 1988). This migration was attributed to active movement toward the layer with optimum light intensity (during periods of daylight and calm) and wind-created shear mixing (dominate in the evenings) that vertically disperses the accumulated population. Rapid population growth, supported by local supply of nutrients on one hand and physical processes on the other hand, are major factors governing the formation and persistence of the patchy population. In an effort to distinguish between physical driving forces and biological processes involved in the patchy phenomenon, we determined the vertical and horizontal distribution of Peridinium population and assessed the physiological status of the population at different sites by analyzing pigment and fatty acid composition.