
Phytoplankton diversity is an important criterion for evaluating the suitability of water for irrigation and drinking purposes. Phytoplankton composition of Chantaru lake, Brahmavara and Manipalla lake, Manipal was studied for a period of one year from June 2013 to May 2014 (see Fig.1).The physicochemical parameters of water such as water temperature, dissolved oxygen, water pH, biological oxygen demand, nutrients such as nitrates and phosphates ware observed and their ranges were 24.5º –30.7º c, 5.59–11.40µg/l, 6.74 – 9.49, 2.89–5.61 µg/l, 21.3–36.5 µg/l, 0.12–4.91 µg/l and 0.21–5.24 µg/l. During the period of investigation 33 species of phytoplankton representing five taxonomic groups such as Cyanophyceae, Chlorophyceae, Euglenophyceae, Bacillariophyceae and Dinophyceae. The Chlorophyceae is dominant than all other forms.