Macrozoobenthic community structure and water quality assessment of Lake Luoma,Jiangsu Province,China

Abstract

2014年1-12月，对苏北骆马湖水质和大型底栖动物进行了逐月调查.根据湖区的生境特征将骆马湖划分为3个区域：采砂区域、植被区域和其他区域.对比分析不同区域水质参数和底栖动物群落结构，并利用《地表水环境质量标准》（GB 3838-2002）、综合营养状态指数和生物学指数对水质进行评价.结果表明，采砂区域的水深显著高于植被区域，而透明度显著低于另外两个区域；采砂区域的总氮、总磷、硝态氮和正磷酸盐浓度均显著高于植被区域，生物多样性显著低于另外两个区域.骆马湖内共采集到大型底栖动物41种，其中环节动物8种，软体动物15种，节肢动物18种.铜锈环棱螺（Bellamya aeruginosa）、苏氏尾鳃蚓（Branchiura sowerbyi）、霍甫水丝蚓（Limnodrilus hoffmeisteri）、长角涵螺（Alocinma longicornis）是现阶段的优势种.10个监测点底栖动物的年均密度和年均生物量分别为77.19 ±43.59 ind./m²和37.62±28.31 g/m²，呈现出较高的空间异质性.生物量较密度空间差异更大，生物量在湖泊四周的监测点较高，而在湖心开阔水域较低.水质评价结果表明骆马湖水质处于中营养状态，总体属于中度污染，作为南水北调东线工程重要的调蓄湖泊以及饮用水源地和水产养殖基地，加强水环境保护不容懈怠.;Physiochemical conditions and macrozoobenthos in Lake Luoma were investigated monthly in 2014.The lake was divided into three regions of the sand mining,the vegetation and the others according to its habitat conditions.Physiochemical parameters and macrozoobenthic community structure were compared among the three regions.Water quality was evaluated based on the surface water environmental quality standard (GB 3838-2002),comprehensive trophic level index and biological indices.The depth of sand mining area was significantly higher than that in the vegetation area,while the transparency was much lower than the other two regions.The concentrations of total nitrogen,total phosphorus,nitrate and phosphate in the sand mining area were significantly higher than those in the vegetation area,while the biodiversity indices of macrozoobenthos were significantly lower than the other two regions.A total of 41 taxa were identified,including 8 species of Annelida,15 species of Mollusca and 18 species of Arthropo-da.Bellamya aeruginosa,Branchiura sowerbyi,Limnodrilus hoffmeister and Alocinma longicornis dominated the community with high abundance and biomass.The annual average density and biomass of macrozoobenthos were 77.19±43.59 ind./m² and 37.62±28.31 g/m²,respectively.Higher spatial heterogeneity was observed for the mean biomass than the mean density.The relative high mean biomass values were found in the littoral sampling sites while the relative low values in offshore sampling sites.It showed that the lake was moderately polluted at a mesotrophic level.As an important water source and aquaculture site,more attention should be paid on water environment protection in Lake Luoma.