Studies on the Rotiferpopulation in relation to some physico-chemical parameters.

Resumo

The present dissertation provides the results of the study done on the Rotiferpopulation of a sewage fed wetland of West Bengal, India, along with the influence of some physico-chemical parameters on them. The water parameters studied were Water temperature (WT), pH, Dissolved Oxygen(DO), Carbon di Oxide(CO2), Total alkalinity(TA), Dissolved Organic Matter(DOM) and Biological Oxygen Demand (BOD).During the study among the above mentioned water parameters WT variedfrom 15.5oCto 32.75oC, pH from 7.98 to 8.75, DO from 4.3 mg/lit to 16 mg/lit, CO2from 00 to 46 mg/lit, TA from 164 mg/lit to 251 mg/lit, DOM from 1.13 mg/lit to 4.73 mg/lit and BOD from 5.62 mg/lit to 28.8 mg/lit.One noticeable feature aboutthe seasonal variation of those parameters in the wetland was that its variation pattern differsin actual magnitude. The wetland had fairly high DO content and pH was always alkaline. The water was also rich in DOM. BOD was moderate and not appreciably high as expected in a polluted aquatic system.The combine effect of above physico-chemical parameters might have promoted the luxurious growth of rotifer population of the wetland.During the study except the above mentioned physico-chemical parameters of water,Rotiferpopulation was also observed.A total of 22 species of 12 generaof rotiferwere noticed during study.Among them 11species were dominant and occur more than six months throughout the study period.This population in the wetland overwhelmingly predominated by Brachionusspecies.Not only that they were also numerically superior over other. Among Brachionusspecies,Brachionus angulariswas most dominant.From the statistical analysis different species of rotifer showed positive correlation with pH and inverse correlation with CO2and TA.