Seasonal dynamics of phytoplankton population and water quality in Bidoli reservoir

Seasonal water quality analysis helps to evaluate the impact of anthropogenic activities on reservoirs. The water quality may be judged by estimating various chemical parameters like dissolved oxygen (DO), free CO₂, total alkalinity, total hardness, pH, Ca⁺⁺, Mg⁺⁺, Cl^-, NO₃^-, SO₄^- bicarbonate, and total dissolved solids (TDS) along with environmental parameters like rainfall and temperature. Most of these abiotic factors are subject to human interventions and are interrelated. This cumulative effect directly influences the biota of the reservoir ecosystem where plankton communities are significant. The current work was carried out with the goal to understand the effect of abiotic factors on planktonic growth in a medium-sized artificial reservoir. The study was attempted to analyze two objectives, which were the variations of parameters with respect to three distinct seasons encountered in the region (summer, monsoon, and winter) and second being the impact of such varying parameters on countable/detectable planktonic diversity. From the water samples collected, 44 genera of planktons belonging to Cyanophyceae, Chlorophyceae, Dinophyceae, Desmids, Bacillariophyceae, and Euglenozoa were identified. There was a marked variation in the seasonal parameters pH, EC, temperature, CO_2, and HCO₃^-. Comparison to the BIS and WHO values shows that though water is not potable, it can be used for agriculture and fishing. Thus, it is necessary that this predominantly rainfed reservoir be maintained for sustainable use.