COMMUNITY CHARACTERISTICS OF THE MACROZOOBENTHOS AND BIOASSESSMENT OF WATER QUALITY IN LAKE DONGHU DISTRICT, WUHAN

Abstract

Ecological surveys in 15 water bodies of Lake Donghu District were carried out during April to September,2008.Altogether 50 macrozoobenthos taxa belonging to 16 families and 41 genera were identified from quantitative samples.There were 28 and 21 taxa in Lake Yandonghu and Qingshangang Channel,respectively,while only 2 or 3 taxa in Lake Beihu,Lake Qingtanhu and Lake Yangchunhu.Standing crops of macrozoobenthos were different in the 15 water bodies.In hypertrophic and eutrophic lakes,macrozoobenthos communities were dominated by oligochaetes and aquatic insects,which were in different proportions.In mesotrophic lake,Lake Yandonghu,aquatic insects and molluscs were the most abundance organisms accounting for 59.1% of density and 96.4% of biomass,respectively.In Qingshangang,oligochaetes and molluscs were the most abundance organisms accounting for 63.6% of density and 99.1% of biomass,respectively.Because the water quality of Lake Yandonghu,which has many taxa preferring clear water,was the best in Lake Donghu District and there were many lotic taxa in the channel of Qingshangang due to its freely connection with the Yangtze River.Shannon-Weaver index(H),Goodnight-Whitley index(GI) and Biotic Index index(BI) were applied to evaluate the water quality of 15 water bodies of Lake Donghu District and other two lakes of Liangzi Lakes,Lake Nanbeizui and Lake Xiaosihai.Results indicated that the bioassessment of Biotic Index was consistent with the trophic state of above mentioned lakes.Therefore the Biotic Index can be used as suitable index of bioassessment of the Lake Donghu District.