东鱼河作为南四湖最长的入湖河流，其水质状况对于南四湖的水环境质量具有重要影响。为分析东鱼河摇蚊群落结构与水体富营养化的关系，于2013年5月对东鱼河8个采样点表层松散2 cm底泥中的摇蚊幼虫头壳进行了分析。东鱼河底泥中共鉴定出30个摇蚊属种，主要属种由Glyptotendipes pallens type（20-42%）、Cricotopus sylvestris type（18-23%）、 Chironomus plumosus type （15-24%）、Tanytarsus mendax type （7-35%）、Dicrotendipes nervosus type （7-12%）、Chironomus anthracinus type （6-23%）、Polypedilum nubifer type （5-38%）组成，共占所有摇蚊含量的79-97%。其中Glyptotendipes pallens type、Cricotopus sylvestris type和Chironomus plumosus type 是东鱼河的优势种，占全流域的53-89%。基于生物多样性指数及主成分分析对东鱼河水质进行分析，结果表明，东鱼河水体处于轻度中度污染等级；冗余分析得到NH3-N是影响东鱼河摇蚊组合分布的主要水环境因子，且不同摇蚊属种对NH3-N的响应不同。此外，结合摇蚊组合生态特性综合分析得，中游、中下游污染较严重，是东鱼河水污染治理的重点区域。

As the longest river discharging into the Nansi Lake,the Dongyu River plays an important role on the water quality of the Nansi Lake.To better understand the relationship between the community structure of chironomid and eutrophication of the Dongyu River,the head shells of larvae preserved in the upper 2cm thick loose bottom sediments were investigated with eight samples collected in May 2013.A total of 30 Chironomus species were identified in the Dongyu River surface sediments.The main genus were composed of Glyptotendipes pallens type (20-42%), Cricotopus sylvestris type (18-23%), Chironomus plumosus type (15-24%),Tanytarsus mendax type (7-35%), Dicrotendipes nervosus type (7-12%), Chironomus anthracinus type (6-23%),and Polypedilum nubifer type (5-38%),accounting for 79-97% of the total counts.Based on the biodiversity index and principal component of the Dongyu River,the water body was in a mild to moderate pollution level.Redundancy analysis showed that NH3-N was the main water environmental factor resulting in the distribution of the chironomid in the Dongyu River,and the responses of different species of Chironomid to NH3-N were varied. It can also be inferred that the Dongyu River is a medium eutrophic river, according to the ecological characteristics of the chironomid combination,with serious pollution in the middle and lower reaches,which are the key areas for water pollution control.

国家自然科学基金（41807430）；江苏省研究生科技创新项目（KYCX18_2122）