On the Dominant Behavior of Zooplankton in Different types of Domestic Sewage Oxidation Ponds

Plankton are small microscopic organisms, comprising diatoms and algae, which form the basis of primary production, whereas zooplankton are mainly crustaceans, rotifers and larval stages of larger animals which constitute the higher aquatic food web. Both are bio-indicators of a water body, constituting the main food for the carnivorous and omnivorous fishes in the aquatic ecosystem. In the present work, a detailed analysis of zooplankton diversity along with variations in species, and seasonal abundance with average and total population density was carried out in different types of domestic sewage oxidation ponds. Similar analysis for a comparison was done in a freshwater control pond situated in Bhopal India. In this study out of 8 ponds, 4 were selected for zooplankton analysis two being primary and two being secondary sewage oxidation ponds and one freshwater control pond was selected for comparative analysis. The results indicated that the number of zooplankton in all ponds ranged from 162 to 14776 org/L, seasonally it was observed that the sewage oxidation ponds had the maximum population of zooplankton in winter, followed by rainy and summer seasons. Regarding the population of zooplankton in the individual oxidation ponds, it was found that sewage secondary pond IIIB had the maximum zooplankton followed by IIIA. Interesting observations on the cascading effects of physicochemical parameters on plankton dynamics, including the variations in the diel population of various species of zooplankton have been recorded. The phenomenon of plankton grazing in different types of domestic sewage ponds is being reported for the first time.