Seasonal Dynamic in Primary Productivity and Phytoplankton Diversity in Berach River System of Udaipur District, Rajasthan

The Berach river basin was studied for phytoplankton diversity and primary production in water from Madar tank to Sarjana tank. This study also included a few isolated ponds of the Berach river such as Up-stream, Daroli and Gadwa ponds. The phytoplankton community in fresh water bodies is primarily responsible for organic production at the primary level. During the study we observed 47 forms of Phytoplankton; they belong to Chlorophyceae, Bacillariophyceae, Desmidiaceae, Dinophyceae and Myxophyceae classes. In the Berach river 47 forms were identified; out of these 17 belonging to Chlorophyceae, 14 to Bacillariophyceae, 10 to Myxophyceae, 3 to Desmidiceae, 2 to Chrysophyceae and 1 to Dinophyceae. The lowest phytoplankton density (4cells/ml) was observed in the winter of 2019 in Downstream Pond and the highest density of 6113 cells/ml was recorded in the summer of 2018 in Udaisagar Lake. The mean density of plankton in the Berach river system ranged from 39.61 to 4222.66 cells/ml during study. The lake Udaisagar, which is characterised by algal blooms, had the highest gross primary production (1.87 gc/m2/day) during the summer of 2018. Primary production was at a minimum (0.12 gc/m2/day) during summer 2019 in Downstream Pond. The highest average phytoplankton density was found in Udaisagar lake (4222.6667 number/litre) followed by Chota Madar tank (3590.1667 number/ litre), Fatehsagar lake (3569.6667 number/litre), Bada Madar tank (3442.1667 number/litre), Sarjana tank (2094.6667 number/litre), Daroli pond (1987.6667 number/litre), Gadwa pond (1467), Upstream pond (1045.8333 number/lit) and minimum density was found in Downstream pond (39.1667 number/ litter).