COMMUNITY STRUCTURE OF MACROZOOBENTHOS AND BIOASSESSMENT OF WATER QUALITY IN COLLAPSE LAKES IN HUAIBEI MINING AREAS

The seasonal investigation on the community structure of macrozoobenthos was carried out in the collapse lakes of Huaibei mining areas (the Qianlong Lake and the Linhuan Lake) in 2013. Twenty-six species were recorded, which belonged to 17 families, 5 classes and 3 phylum. The average density of macrozoobenthos was 230.85 ind./m2 in the Qianlong Lake and 151.3 ind./m2 in the Linhuan Lake. The average biomass of macrozoobenthos was 56.11 g/m2 in Qianlong Lake and 36.38 g/m2 in Linhuan Lake. The dominant taxa of macrozoobenthos were chironomids, Limnodrilus hoffmeisteri and Branchiura sowerbyi. The density of the macrozoobenthos in both lakes was the highest in summer. Mollusca and aquatic insects were the dominant species in the biomass of macrozoobenthos. The biomass of macrozoobenthos in summer and autumn was significantly higher than in spring and winter. The water quality was assessed according to Shannon index, Margalef index and Biotic index. It was suggested that Biotic index, but not Shannon index represented a suitable bioassessment of the water quality in collapse lakes of Huaibei mining areas. The combined results of Margalef index and Biotic index indicated that the water pollution was light in spring and in winter, but moderate in summer and in autumn.