长江中下游干流滨岸带大型底栖动物群落结构及水质生物学评价

Macrozoobenthos Community Structure and Biological Evaluation of Water Quality in Littoral Zone of Middle and Lower Reaches of Yangtze River

长江干流滨岸带对大型底栖动物具有非常重要的生态作用。然而,有关长江中下游滨岸带水质生物学评价状况尚未可知,大型底栖动物受岸线利用类型的影响也值得进一步探究。为评估长江中下游干流滨岸带水生态环境,2017年5月对沿江近岸53个样点的大型底栖动物和水环境因子进行调查。双壳纲、腹足纲、软甲纲和多毛纲在中下游滨岸带的分布差异较大,与盐度、流速、附着基质及沉积物粒径等因素有关。生物学污染指数(BPI)显示长江中下游水体处于轻度—中度污染,入海口附近异常低的BPI值可能与多毛纲和淡水壳菜大量生长有关。非度量多维度排序(NMDS)分析结果表明大型底栖动物受氨氮、硝态氮、磷酸盐、叶绿素a、多环芳烃(PAHs)和有机氯农药(OCPs)的影响较为显著;且河蚬、中国淡水蛏、淡水壳菜、铜锈环棱螺、方格短沟蜷、光滑狭口螺和日本沼虾主要分布于湿地和自然岸段附近,摇蚊幼虫和寡毛纲多位于城市和河口岸段。大型底栖动物群落结构分布受到岸线利用类型和理化因子的制约,为长江经济带岸线资源调查评估及水生态系统管理和保护提供了科学依据。

The littoral zone of the Yangtze River mainstream has a very important ecological role for macrozoobenthos.However,the status of water quality biology assessment in the riparian zone of the middle and lower reaches of the Yangtze River is not yet known,and the influence of macrobenthos by shoreline use type deserves further investigation.In order to assess the aquatic ecological environment in the littoral zone of the middle and lower reaches of the Yangtze River,this study conducted a sampling survey of macrobenthos and water environmental factors at 53 representative sample sites along the river in May 2017.The distribution of bivalves,gastropods,mollusks and polychaetes in the middle and lower reaches riparian zone varied greatly,related to salinity,flow velocity,attached substrate and sediment grain size.The Biological Pollution Index(BPI)shows that the water bodies in the middle and lower reaches of the Yangtze River are in mild-moderate pollution,and the anomalously low BPI values near the mouth of the estuary may be related to the massive growth of polychaetes and Limnoperna fortunei.The results of non-metric multidimensional ranking(NMDS)analysis showed that macrozoobenthos was more significantly affected by ammonia nitrogen,nitrate nitrogen,phosphate,chlorophyll a,polycyclic aromatic hydrocarbons(PAHs)and organochlorine pesticides(OCPs).It also suggested that Corbicula fluminea,Novaculina chinensis,L.fortunei,Bellamya aeruginosa,Semisulcospira cancelata,Stenothyra glabra and Macrobrachium nipponense were distributed in wetlands and natural bank sections while Chironomid larvae and oligochaetas were in urban and estuary sections.The distribution of the macrozoobenthos community structure was constrained by the utilization types and physicochemical factors,which provided a scientific basis for the survey and assessment of shoreline resources and for the management and protection of aquatic ecosystems in the Yangtze River Economic Zone.