河口大型工程对长江河口底栖动物种类组成及生物量的影响研究

Studies on the Impacts of Large-Scale Estuarine Engineering on Species Composition and Biomass of Benthos in the Yangtze River Estuary

2002 年 5—6 月对长江口深水航道治理一期工程区域底栖动物进行了取样调查,研究分析了工程区域底栖动物种类组成和生物量分布特征。结果表明:① 底栖生物 19 种,与 1982—1983 年和 1998 年相比,分别减少 87.6 % 和 20.8 %,优势种为纽虫和沙蚕,出现率分别达 32 % 和 24 %;② 平均密度 21.8 个/ 2 2m ,比 1998 年下降 65.9 %;③ 平均生物量为 5.68 g/m (湿重),比 1982—1983 年下降 76.5 %;④ 一期工程对长江河口生态系统结构已产生影响,河口底栖动物种类组成及生物量的变化与长江口深水航道治理一期工程引起的区域局部小尺度海洋水流发生改变,并导致航道沉积物受冲刷和底质属性发生改变有关。鉴于此,建议对河口大型工程对河口生态系统的综合影响进行动态监测和生态恢复。

A complete survey of benthos in the regions of deep-channel regulation of the Yangtze River Estuary was conducted from May to June 2002. The characteristics of species composition and biomass of benthos were studied and analyzed. The results showed that: ( 1 ) 19 benthos were found this time. In contrast with the results in 1982—1983 and 1998, it decreased by 87.6 % and 20.8 % respectively in species number. The dominant species were Anopla and Nereidae with existing frequencies of 32 % and 24 % respectively. ( 2 ) Average density was 21.8 individual s/m2, decreasing by 65.9 % in contrast with that in 1998. ( 3 ) Average biomass was 5.68 g/ m2, decreasing by 76.5 % in contrast with that in 1982—1983. ( 4 ) The impacts by the No.1 project has influenced the ecosystem structure in the Yangtze River Estuary. The variation of benthic species composition and biomass in the Yangtze River Estuary was related to the change of local small-scale sea water currents caused by the No.1 project of deep-channal regulation. Therefore, dynamic monitoring on the influences of large-scale estuarine engineering on estuarine ecosystem and ecological restoration in the Yangtze River Estuary is emergent.