Seasonal variations of phytoplankton community structure in relation to Physico-chemical factors in Lake Kolleru, Andhra Pradesh, India

In order to study the seasonal variations in the structure and dynamics of phytoplankton community of the Kolleru lake in Andhra Pradesh, water samples were collected in each season during January to December 2009. Seasonal variations, biodiversity indices and correlation coefficient of phytoplankton were studied during the period. Fifty six species of phytoplankton belonging to Chlorophyceae (35 species), Bacillariophyceae (6 species), Cyanophyceae (12 species) and Euglenophyceae (2 species) were identified. The highest phytoplankton abundance was observed in summer and the lowest in winter. The maximum and minimum species richness (Menhinick index R2) were found to be 1.25 at station 2 and 1.13 at station 3 respectively. Maximum and minimum species diversity (H 1 ) were found at station 4 and station 5 (3.85) and station 2 (3.67). Maximum species evenness (0.94) was recorded at stations2 and 4 and minimum species evenness was recorded at station 1 (0.89). The preponderant and sub-preponderant species changed in accordance with the seasons. Pearson correlation analysis was used to investigate the relationship between environmental factors and phytoplankton community. The present investigation revealed that the distribution of plankton species depended upon the environmental and physicochemical parameters.