Monthly variation of physico-chemical parameters and zooplankton density in Kangsabati Reservoir, West Bengal, India

The present investigation provides information about physico-chemical parameters and zooplankton density which was carried out on monthly basis for the period of one year from march- 2010 to February -2011 at three different stations of Kangsabati Reservoir which is a freshwater ecosystem. Various parameters including temperature, conductivity, transparency, pH, dissolve oxygen, free CO2, total alkalinity, chloride, phosphate, total inorganic nitrogen, total hardness were analyzed. Phosphorus and total inorganic nitrogen were at peak in rainy season. Water temperature varies with air temperature ranging 2.26 0C to 11.41 0C. Chlorinity, salinity, alkalinity were high in summer season and low in winter month. Transparency was maximum in winter season and minimum in rainy season. The result envisages that there were wide fluctuations in some physico- chemical parameters where as few parameters were in the normal range throughout the study period and indicated better water quality of the reservoir. During study period total 39 genera of zooplankton were identified in five groups such as Rotifera (12 genera),Copepoda (12 genera), Cladocera (10 genera), Ostracoda (2 genera) and Protozoa(3 genera).The highest number of zooplankton was recorded in May-2010 months (743 Ind./L) and lowest in July-2010 months (169 Ind./L).