Use of Biotic Community Structure as a Measure of Ecological Degradation

The benthic macroinvertebrate communities of two lotic aquatic habitats,namely,the Churni River(C-R)and the Jalangi River(J-R)were compared in this study.One lotic aquatic system(C-R)was polluted by organic pollutants due to discharge of unprocessed sewage water,while the other(J-R)was not affected by such pollution.Evaluations of various physico-chemical properties of water,sediment and different macroinvertebrate communities of the two tropical lotic systems were done in a period from January,2002 to December,2003.A long term temporal change in the macroinvertebrate communities was recorded due to increase in sediment rH value.Sediment redox potential affected by the anthropogenic activities was found to be an important factor for alteration of macroinvertebrate communities in these aquatic ecosystems.A positive correlation has been established between rH and Margalef index in this study.Potassium and the total count of coliform bacteria in water showed significantly higher values for the polluted Churni River than those for the Jalangi River.Fig 3,Tab 4,Ref

The benthic macroinvertebrate communities of two lotic aquatic habitats, namely, the Churni River （C-R） and the Jalangi River （J-R） were compared in this study. One lotic aquatic system （C-R） was polluted by organic pollutants due to discharge of unprocessed sewage water, while the other （J-R） was not affected by such pollution. Evaluations of various physi- co-chemical properties of water, sediment and different macroinvertebrate communities of the two tropical lotic systems were done in a period from January, 2002 to December, 2003. A long term temporal change in the macroinvertebrate communities was recorded due to increase in sediment rH value. Sediment redox potential affected by the anthropogenic activities was found to be an important factor for alteration of macroinvertebrate communities in these aquatic ecosystems. A positive correlation has been established between rH and Margalef index in this study. Potassium and the total count of coliform bacteria in water showed significantly higher values for the polluted Churni River than those for the Jalangi River.