IMPACT OF SEASONAL CHANGES IN FRESHWATER PHYTOPLANKTON AND ZOOPLANKTON BIODIVERSITY AT VALANKULAM LAKE, COIMBATORE DISTRICT, TAMIL NADU, INDIA

The plankton communities are important source of food for the aquatic organisms, and if any undesirable changes in aquatic environment may affect plankton diversity and density. Therefore, assessment of planktonic communities in the freshwater ecosystems is essential because they serve as bio-indicators of water quality parameters. Hence, the present research was focused to evaluate the freshwater phytoplankton and zooplankton diversity and their abundance in Valankulam Lake (Lat. 10.59° N and Long. 76.57° E), at Coimbatore city, Tamil Nadu, India. Results from the study revealed that a total of 77 species of phytoplankton and zooplankton were recorded, under 37 families and 46 genera. In addition to that, a total of 43 phytoplankton species were recorded under 25 families and 30 genera, (which includes; 15 species of Cyanophyceae, 17 species of Chlorophyceae, 08 species of Bacillariophyceae, 03 species of Euglenophyceae). and a total of 34 species of zooplankton were recorded under 12 families and 17 genera, (which includes 13 species of Rotifera, 09 species of Cladocera, 08 species of Copepoda and 04 species of Ostracoda). The maximum plankton diversity was observed during the monsoon season and the minimum in the summer season. Results from study revealed the ecological status of the lake is categorized as moderately polluted due to the presence of municipal waste and industrial discharges into the lake water. Therefore, the assessment of planktonic communities in water bodies will be useful to monitor and maintain the water quality parameters and wealth of aquatic biota in the aquatic ecosystem.