Phytoplankton diversity in relation to physico-chemical environmental variables of Nachiketa Tal, Garhwal Himalaya

Abstract

The study deals with the assessment of physico-chemical parameters and phytoplankton diversity of Nachiketa Tal. The lake was monitored for one annual cycle (May 2014-April 2015). A total of 71 taxa of phytoplankton belonging to 57 genera were recorded. Phytoplankton in the lake are represented by six major families, Bacillariophyceae (22), Chlorophyceae (37), Cyanophyceae (6), Xanthopyceae (2), Dinophyceae (2) and Euglenophyceae (2). The overall phytoplankton density was found to be abundant (1401±325.60 ind. l-1) in winter season, declined in monsoon season (457.50±17.83 ind. l-1) but the population of Cyanophyceae and Euglenophyceae was found to be high (174.33±37.09 ind. l-1) and (24.33±5.89 ind. l-1) respectively in summer season. Results showed that the increases in turbidity, TDS in monsoon season are the driving factors for decreasing the phytoplankton density in the lake. Pearson’s correlation and CCA calculated between environmental variables and phytoplankton diversity showed that the distribution of phytoplankton in the lake is dependent on the variabilities of physico-chemical variables.