ABSTRACT: Phytoplankton biodiversity and water quality of national wetland, Sukhna Lake, Chandigarh (Lat. 30° 44''14 N, Long. 76° 47'' 14 E), India were examined in the present study. During the present study (April 2009 to September 2009), phytoplankton composition and physico-chemical characteristics of water are indicative of mesotrophic condition in three different collection zones (ZA, ZB and ZC) of the lake. The species richness displayed fair variety of algal species (89 taxa). The community was dominated by the members of chlorophyceae and cyanophyceae. Highest phytoplankton density (2082 individual/ L) and species diversity (0.928-2.628) was found during the summer season in the wild area (ZA) where there was no anthropogenic activity. The area with maximum disturbance in water column (ZC) showed minimum phytoplankton density (164/L) and species diversity (0.991-2.319). Phytoplankton densities have significantly positive correlation with TDS(r= 0.669, significant at 0.05 level), chloride(r= 0.717, significant at 0.05 level) and significantly negative correlation with BOD(r= 0.623, significant at 0.05) in ZA and significantly positive correlation with bicarbonate alkalinity(r= 0.728, significant at 0.01 level) and calcium hardness(r= 0.672, significant at 0.05 level) in ZB.
Key words: Lake Sukhna; Ecology; Physicochemical parameters; Phytoplankton; species diversity.