Community structure of macrozoobenthos and the evaluation of water environment in Lake Baima, Jiangsu Province, China

Abstract

To characterize the community structure of macrozoobenthos and evaluate the water environment in Lake Baima, macrozoobenthos were investigated at 11 sites of Lake Baima monthly in 2016. Water quality was evaluated based on the Environmental Quality Standards for Surface Water (GB3838-2002, in Chinese), comprehensive trophic level index and biological indices. A total of 16 species were recorded, belonging to 4 phyla, 16 orders, including 8 chironomids, 3 oligochaetes, 2 Mollusca, and 3 other species. The mean density and biomass of macrozoobenthos were 277.06 ind./m2 and 31.3953 g/m2, respectively. Tanypus chinensis, Limnodrilus hoffmeisteri, Branchiura sowerbyi, Propsilocerus akamusi, Chironomus plumosus and Bellamya sp. were the dominant species in Lake Baima. Higher spatial heterogeneity was observed for the mean biomass than the mean density. The highest density was recorded in the central sites, and relatively lower values were observed in the offshore sites. The biomass presented the opposite distribution pattern compared with density. It showed that the lake was moderately polluted at a mesotrophic level, and the eutrophication strongly influenced the structure of macrozoobenthic assemblages in Lake Baima. As an important water source and aquaculture site, more attention should be paid on water environment protection in Lake Baima.