ABSTRACT

 

The phytoplankton present in various water bodies collectively account for around half of the earth’s primary producers. The present study attempts to gain a better insight into the phytoplankton diversity and its relationship with physico-chemical parameters of freshwater lake Kharungpat in Manipur, India from September 2019 to August 2021. The lake water was characterized by moderate temperature (16.68-29.21 oC), fluctuating transparency (53.00-119.30 cm), suitable level of pH (6.26-7.74) and dissolved oxygen (5.10–9.35 mg/l), favorable total alkalinity (31.21-66.29 mg/l), total hardness with a value of 28.37-66.49 mg/l which can sustain low growth of fish, fluctuating level of free carbon dioxide (3.78-10.23 mg/l), phosphate phosphorus and nitrate nitrogen content with a value ranged from 0.001 to 0.018 mg/l and 0.01-0.30 mg/l. A total of 22 phytoplankton genus were identified in the lake, out of which 13 belonged to Chlorophyceae, seven to Cyanophyceae, six to Bacillariophyceae and two to Euglenophyceae. Chlorophyceae, Cyanophyceae, Bacillariophyceae and Euglenophyceae are the four major phytoplankton groups identified with a percentage composition of 51.79%, 31.00%, 13.12% and 4.33% respectively. An analysis of seasonal variation of phytoplankton diversity indices indicated that the highest recorded Simpson_1-D was 0.956 and 3.180, 4.023 and 0.976 for Shannon_H, Margalef and Equitability_J respectively.

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Keywords    Phytoplankton, Seasonal variation, Diversity, Freshwater, Lake Kharungpat.