汉阳湖群底栖动物群落及其对环境质量的指示

MACROBENTHOS COMMUNITIES AND BIO-ASSESSMENT OF LAKES IN HANYANG DISTRICT

汉阳地区湖汊纵横、水系丰富,是汉阳地区工业和生活废水的主要纳污水体,水质多为劣V类。底栖动物已被广泛用于监测湖泊有机污染,因此,为探明汉阳地区湖泊群（三角湖、墨水湖、龙阳湖、月湖、后官湖）的污染状况和污染分布格局,于2002~2005年全面调查了各湖泊的底栖动物群落,并分析了其对环境的指示作用。除后官湖发现软体动物外,其他各湖泊均以耐污的颤蚓科寡毛类（霍甫水丝蚓,苏氏尾鳃蚓）和摇蚊科幼虫（长足摇蚊、红裸须摇蚊、羽摇蚊）占绝对优势。统计分析表明,颤蚓类和摇蚊幼虫的密度与水体氮、磷、叶绿素含量呈显著正相关（p〈0.05）,且颤蚓类密度对水体氮、磷水平的预测能力（R2）优于摇蚊幼虫。K-优势曲线和多样性指数的污染评价结果显示,墨水湖和龙阳湖属重污染,月湖和三角湖属中度污染,后官湖属轻度污染,这与理化指标表征的营养状况基本吻合,特别是在受苯酚化工废料污染的龙阳湖东片没有采集到底栖动物,这是底栖动物能够监测污染物长期效应的例证。进一步应用颤蚓类密度的水平分布指示了各湖泊的沉积物污染分布,结合湖体周边环境分析论证了这种指示作用的可信度。

There are plenty of small lakes distributed in Hanyang District,and these lakes are almost belonging to type V of water quality due to the inputting of industrial and domestic waste water.Macrobenthos has been widely used to monitor the organic pollution.To detect the extent and distribution of pollution in these lakes（Sanjiao Lake,Moshui Lake,Longyang Lake,Yue Lake,Houguan Lake）,this study made investigations of macrobenthos community and researches on their indication to lake environment during 2002~2005.Besides of Houguan Lake with one species of mollusca,the other lakes were only inhabited by pollutant-tolerant species,i.e.tubificids（e.g.Limnodrilus hoffmeisteri,Branchiura sowerbyi） and chironomids（Tanypus sp,Propsilocerus akamusi,Chironomus plumosus）.Statistical analyses revealed that densities of tubificids and chironomids were significantly positively correlated with total nitrogen,phosphorus and Chla（p0.05）.The correlation coefficients（R2） of regression between tubificid densities and nutrients（TN,TP） were higher than that of chironomids,which indicated that the tubificid densities were more reliable for predicting trophic level than chironomid.The result of water quality bio-assessment was almost consistent with the physical-chemical evaluation,i.e.Moshui Lake and Longyang Lake were severely polluted,Yue Lake and Sanjiao Lake were moderately polluted and Houguan Lake was slightly polluted.Not any macrobenthos was collected in the eastern phenol-polluted area of Longyang Lake,which validated the monitoring role of macrobenthos in the long-term effect of pollution.Furthermore,this study utilized the spatial pattern of tubificid to indicate the pollution pattern of these lakes.On the basis of environmental analyses,this study validated the reliable role of tubificid in monitoring organic pollution.