The growth of Mangroves along backwaters of Ennore creek, Tamil Nadu, India was selected for the present study. Study was undertaken every month for the period of one year from January to December 2021. Four decisive stations were identified for survey to bring out seasonal consequences. The phytoplankton community was investigated by estimating population through adopting qualitative and quantitative analysis such as species composition, percentage composition, density, diversity, richness, evenness. Supportive parameters viz. nitrate, silicate and phosphate were also examined. Meanwhile, regulating parameters such as temperature, salinity, pH, dissolved oxygen were also investigated. Three groups such as Bacillariophyceae, Cyanophyceae and Chlorophyceae were identified with 37, 31 and 18 (nos.) species, respectively. The phytoplankton density was observed as 280 to 8050 cells/l. Recorded density was lower compared to other ecosystems and back waters, the community structure of phytoplankton population still thriving due to supportive parameters as documented in the presented study. Despite, the recorded high level of BOD, COD, heavy metals and regulating parameters not conducive, the population of phytoplankton community has affluently sustained and made sustain other biota in vicinity, which can still regulate the carrying capacity of Ennore back waters by acting effectively as primary producers in the system.

Hydrobiology regulates the plankton diversity in a water body and is a fundamental research area in aquatic and ecological studies. The present study was carried out to assess the zooplankton diversity and physicochemical parameters viz. temperature, salinity, pH, phosphate and nitrite by collecting water samples at four stations in Ennore estuary for the period of one year from January to December 2021. Investigation of species diversity, composition, richness and evenness predicted that the diversity status of zooplanktons is influenced by the hydrobiology of Ennore backwaters.