Abundance of Genus Brachionus (Rotifer) of a Freshwater Wetland of district Howrah, West Bengal, India

Abstract

The materials for the present limnological investigation were collected from the subsurface water of a managed fresh water wet land for one year. The wetland water is under domestic use (bathing and washing purpose). There is no sewage influx in this wetland. No macro vegetation is kept in this wetland as it is profusely used for pisciculture by using supplementary feed and fertilizer periodically round the year. The water parameters studied were pH, Dissolved oxygen (DO), Carbon di oxide (CO2), Alkalinity, Hardness and Biological oxygen demand (BOD). In this study pH was always found to be alkaline and varied from 7.78 to 8.31. During the study DO showed its maximum fluctuation after CO2 and varied from 4.4 to 11.4 mg/lit while CO2from 4 to 21 mg/lit. On the other hand alkalinity ranged from 138.5 to 252 mg/lit, hardness from 28.4 to 80 mg/lit and BOD from 1.2 to 8.3 mg/lit. The combined effect of the above physicochemical parameters might have promoted the growth of the Brachionus spp.