Assessing the phytoplankton community and diversity in relation to physico-chemical parameters in a tropical reservoir of the River Ganga basin, India

Phytoplankton species composition and diversity and its relation to physico-chemical parameters were studied in Jargo Reservoir located on River Jargo, a tributary of River Ganga basin, India. A total of 137 phytoplankton species belonging to 8 divisions were recorded indicating rich phytoplankton diversity in the North Indian reservoir. Bacillariophyta contributed the highest number of species followed by Chlorophyta. Filamentous algae such as Geitlerinema sp., Pseudoanabaena sp., Oscillatoria sp. and Phormidium sp. were highly abundant. The contribution of the top ten species ranged between 63% and 98% of total phytoplankton density. PCA analysis of physico-chemical revealed six principal components (HCO3, TDS, BOD, DOM, air temperature and pH) which significantly affected the succession of phytoplankton in Jargo Reservoir. The CCA analysis of phytoplankton species and physico-chemical parameters revealed that Ochrophyta and Miozoa were highly influenced by high CO2 and PO4. Higher phytoplankton diversity and species richness were observed during the late winter season and rainy season, respectively. Our investigation recommends that fish production in the reservoir could be enhanced by stocking with fingerlings of silver carp, which has the potential to utilise the unconsumed population of abundant Myxophyta.