Effects of chlordane and heptachlor on the marine dinoflagellate, Exuviella baltica, Lohmann.

Chlordane and heptachlor at 50 gmg/1 reduced cell density, chlorophylla per unit volume of culture,14C uptake per cell and carbon fixation per unit of chlorophylla in the marine dinoflagellateExuviella baltica Lohmann. The concentration of chlorophylla per cell was not reduced, however, by treatment with either compound. Chlordane was more toxic than heptachlor at this concentration, and caused the disintegration of many cells, thus affecting particle size distribution in the cultures. In nature, such an inhibition and shift in size class distribution could affect the availability of food for particle-feeding herbivores.