STUDIES ON THE ECOLOGY OF PHYTOPLANKTON IN CUDDALORE-UPPANAR BACKWATER, SOUTHEAST COAST OF INDIA

Salinity was observed as an important controlling factor in determinin g the species composition and succession. Temperature was found to be a co-variate with other factors and was not having direct influence on phytoplankton abundance. The population density showed marked seasona l variations. Diatoms were dominant followed by dinoflagellates. The g enus Chaetoceros was represented with a maximum number of 17 species. Asterionella japonica, Coscinodiscus marginatus, Nitzschia closterium, Thalassiothrix frauenfeldii, Skeletonema costatum Ceratium furca and Peridinium depressum occurred almost all through the year and contribu ted substantially to the phytoplankton density.