IDENTIFICATION OF PLANKTON COMMUNITY AND THEIR INTER-RELATIONSHIP WITH PRIMARY PRODUCTIVITY OF KAPTAI LAKE

Abstract

The present study was carried out in Kaptai Lake from September, 2021 to February, 2022; for a period of six months to identify the plankton community and establish a relationship between plankton abundance and primary productivity of Kaptai Lake. A total of 15 genera of phytoplankton were identified under the classes Chlorophyceae, Cyanophyceae, Dinophyceae and Euglenophyceae from Kaptai Lake; among which Chlorophyceae was the dominant class. Identified phytoplankton genera were Actinastrum, Cosmarium, Chlamydomonus, Mougeotia, Pandorin, Pediastrum, Spirogyra, Staurastrum, Xanthidium, Zygnema, Anabaena, Aphanothece, Gleocapsa, Ceratium and Phacus. The highest total phytoplankton abundance in Kaptai Lake was recorded to be 32.22 × 103 cells/L in October whereas the lowest value was observed to be 11.21 × 103 cells/L in January. A total of 8 genera of zooplankton were identified under the groups Rotifera, Crustacea, Arthropoda and Protozoa; among which, Rotifera was the dominant group. Identified zooplankton genera were Brachionus, Euchlanis, Keratella, Polyarthra, Asplanchna, Nauplius, Cyclops and Paramecium. The highest total zooplankton abundance in Kaptai Lake was recorded to be 5.06×103 cells/L in October whereas the lowest value was observed to be 1.92×103 cells/L in January. Mean gross primary productivity of Kaptai Lake throughout the period of study was (359.16 ± 104.51) mgC/m3/day and net primary produtivity was (209.81 ± 60.87) mgC/m3/day. Phytoplankton abundance showed a statistically significant, strong positive correlation with zooplankton abundance; as well as a moderate positive correlation with gross primary productivity (p < 0.05).