Vol. 9, Issue 6, Part E (2023)

The present studies were made on the enumeration of phytoplankton with respect to physico-chemical parameters in Tumbadi Lake of Koratagere in the state of Karnataka. Composite water samples were collected from designated stations at surface level during summer, winter and rainy seasons from January 2020 to December 2020. Total of 49 species of phytoplankton were identified under 31 genera belonging to 5 different taxonomic groups with seasonal maxima during summer. Bacillariophyceae with 36.65% dominated the other groups fallowed by Cyanophyceae (22.45%), Chlorophyceae (20.40%), Desmidaceae and Euglenophycean each with 12.24%. It is evident from the results that, Chlorophyceae did not supported by any of the physico-chemical parameters where as some of the physico-chemical parameters had indirect bearing on the population of Desmids and Euglenoids. Density of Diatoms was positively supported at significant level by air temperature and concentration of pH and nitrate having negative a correlation with silica. Blue greens were significantly supported by nutrient elements such as nitrate, phosphate and sulpahate. Mixophycean and Euglenophycean indices of Nygaard for water pollution indicated that the lake is oligotrophic. However, It is urged the local governmental authorities to control the anthropogenic activities and save the lake from further anthropogenic disturbances for the welfare of the present and future generations.