Conclusion

The water quality parameters play a decisive role in the structure and composition of phytoplankton in aquatic ecosystems. The water quality and phytoplankton community structure varied among the monitored 15 lakes of Vrishabhavathi valley, Greater Bangalore, Karnataka. Mallathahalli lake had higher levels of ionic pollution, while Kempambudhi lake showed higher levels of organic and nutrient pollution. A total of 58 genera of phytoplankton belonging to 5 phyla such as Chlorophyta, Bacillariophyta, Cyanobacteria, Charophyta, and Euglenozoa were recorded in the monitored 15 lakes. Cyanobacteria formed blooms in Doraikere Uttarahalli, ISRO layout, and Yediyur lakes in Vrishabhavathi valley, threatening aquatic life. CCA results revealed that turbidity, total hardness, calcium, magnesium, and alkalinity influences phytoplankton community structure and composition. Palmer index revealed that Doraikere, Deepanjali Nagar, Srinivasapura, and Hosakerehalli lakes had moderate pollution. In contrast, ISRO, Uttarahalli, Sankey, Yediyur, Sompura, Ullal, Hemmigepura, Konasandra, Dubasipalya, Mallathahalli, and Kempambudhi lakes had high organic pollution. Hence, phytoplanktons are helpful as bioindicators of water quality and aid asa low-cost tool for monitoring lakes. This study will serve as a baseline for wetland protection and biodiversity conservation and help various stakeholders decide to control pollution from domestic and industrial sources.

Acknowledgments

We thank the ENVIS Division, The Ministry of Environment, Forests and Climate Change, Government of India, and Indian Institute of Science (IISc) for supporting to ecological research.