Impact of Physico-Chemical Characteristics on Phytoplankton Diversity of Nalligudda Lake, Bangalore

Physico-chemical parameters of water are a prime consideration to assess the water quality of a lake for its best utilization for drinking, irrigation and fisheries. In the present investigation, the study of monthly variation of different physico-chemical characteristics and phytoplankton diversity were carried out from January to December 2011 to know the water quality of Nalligudda Lake of Bangalore. Physico-chemical parameters of the water samples such as water temperature (24.2-32.3.C), pH (7.1-8.5), total dissolved solids (300-800 mg/L), electrical conductivity (468.75-1250 µmhos/cm), dissolved oxygen (3.9-7.15), biological oxygen demand (2.4-7.2), chemical oxygen demand (9.9-41.4), phosphate (0.32-3.1 mg/L) and nitrate (2.86-6.4 mg/L) were recorded in the present investigation. Totally 51 species of phytoplankton belonging to different taxonomic groups were identified. Among these, 22 species belonged to Chlorophyceae, 8 species to Euglenophyceae, 2 species to Chrysophyceae, 2 species to Dinophyceae, 10 species to Bacillariophyceae and 7 species to Cyanophyceae. Chlorophyceae formed the dominant group. Dominance, Shannon index, Simpson index and Evenness of the species were also calculated.