Cyanobacterial flora and the physico-chemical environment of six tropical fresh water lakes of Udaipur, India

The cyanobacteria and physico chemical environments of six tropical fresh water lakes of Udaipur, India were investigated. These lakes receive varying nutrient inputs from different sources. Altogether 51 species of cyanobacteria were recorded. Species composition varied between lakes and between seasons. Lake VI (Baghdara), which receives nutrients from natural sources only, differed considerably from the others in water chemistry and composition of dominant species. Lake II (Swaroop Sagar), eutrophied due to sewage inputs, was species poor. Non diazotrophs, represented by 27 species, dominated during summer. With few exceptions, N 2 fixing species, both heterocystous and unicellular diazotrophs (represented by 24 species), were dominant during winter. Microcystis aeruginosa, Phormidium sp. and Anabaena flos aque were the dominant taxa of lakes characterized by sewage eutrophication. The study shows that both species diversity and community composition were affected by water chemistry.