上海临港新城滴水湖生态系统健康评价

Ecosystem health assessment of the Dishui Lake in Lingang New Town,Shanghai

为了对临港新城的水利调度中心——滴水湖做出科学、全面的生态系统健康诊断,结合滴水湖表层水体和湖泊底泥的理化性质、生态特征指标和临港新城的社会发展状况,筛选构建最小数据集的指标,并依据各指标的特性选择合适的评分标准,再利用层次分析法得出指标的权重值,最后根据评价分级对滴水湖生态系统健康状况做出评价.本研究共筛选得到15个指标构成滴水湖生态系统评价模型的最小数据集,包含了水体DO、TP和底泥TOC、TP、Hg、As、Cu、Zn、Chl-a、浮游植物生物量(BA)、能质(Ex)、结构能质(Exst)、申港街道人口密度、滴水湖景区年接待游客量、绿化覆盖率等.评价结果显示,2012年冬季、2013年春季和夏季滴水湖生态系统健康指数分别为0.76、0.71和0.69,总体上处于"较健康"的稳定水平,与实际情况相符,也证明了滴水湖水体近年来处于中、轻度富营养化状态.研究表明,目前制约滴水湖生态系统健康的主要因子为底泥TP、BA和Exst,需要继续控制人为外源P排放入湖,提高上游来水水质,增加浮游生物量以提高生态系统的结构能质.

To make a scientific comprehensive diagnosis of the ecosystem health situation of the Dihsui Lake,the center of water control in Lingang New Town,the surface water and sediment samples of the Dishui Lake as well as ecological characteristics and social economy situation were used to select the minimum data set of ecosystem health assessment. According to the characteristic of each indicator and analytic hierarchy process( AHP),an appropriate scoring standard and weight can be determined,which is necessary to make an evaluation of the Dishui Lake ecosystem health situation. The study showed that totally fifteen indicators from three aspects,including DO,TP of surface water,TOC,TP,Hg,As,Cu,Zn of sediments,Chl-a,Ex,Exst,population density,the amount of annual tourists and the percentage of green coverage,were selected into the MDS. The results of evaluation indicated that the ecosystem health indexes of the Dishui Lake in winter( 2012),spring and summer( 2013) was 0.76,0.71 and 0.69 respectively,which showed that the lake was in the stable' less healthy level'. This consequence was similar to the fact that the lake was in the situation of mild eutrophication in recent years and revealed that the key restrictions of the Dishui Lake are TP,BA and Exst. Therefore,it is necessary to control the exogenetic P discharged into the lake to improve the water quality of upstream runoff and to increase the amount of plankton in order to make the structural eco-energy better.