A Comparative Study on the Occurrence, Density and Seasonal Variations of Phytoplankton and Zooplankton in a Perennial Pond Ecosystem of Tripura, India

Abstract

The present study makes a comparative record on the density and seasonal variations of phytoplankton and zooplankton in a perennial pond ecosystem of Tripura during a period from March 2019 to February 2021. The present observation recorded the presence of 19 species of phytoplankton out of which 13 species under the class Chlorophyceae, 4 species under the class Cyanophyceae, 2 species under the class Bacillariophyceae and 1 species under the class Euglenophyceae and 17 species of zooplankton out of which 11 species of rotifer, 3 species of cladocera, 2 species of copepod and 1 species of ostracod in the studied pond. The percentage composition of different families under which different phytoplankton species exist was noted as well as percentage composition of each phytoplankton species was also noted. The percentage composition of different families under which different zooplankton species exist was also noted as well as percentage composition of each zooplankton species was also noted. Amongst the recorded different phytoplankton species, Merismopedia sp. was found to be dominant while Brachionus angularis was the dominant species in zooplankton. Seasonal variations of different groups of phytoplankton followed a definite rhythm of seasonal succession showing highest density in summer and lowest density in monsoon. As regards to seasonal variations of zooplankton, rotifer fauna showed highest density in winter and lowest density in summer while, cladoceran zooplankton showed its highest density in the summer and lowest density in monsoon. Similar trend of seasonal successions were also noticed in copepod and ostracod zooplankton as observed in cladoceran zooplankton during two years study period. Notable physico-chemical factors of the studied pond were also noted. The study infers that phytoplankton and zooplankton although have different environmental requirements, many of them co-exist in the same water body, their abundance may vary with seasons due to dynamic nature of the aquatic ecosystem and might be also due to optimal condition in the physico-chemical parameters of the lentic ecosystem. The present observation also presumed that the densities of phytoplankton and zooplankton are not controlled by a single factor but multiple factors conjointly governs over the seasonal abundance of phytoplankton and zooplankton in different degrees in the studied pond ecosystem.