西湖浮游植物的演替及富营养化治理措施的生态效应

The succession of phytoplankton and the ecological effects of eutrophication control measures in Hangzhou West Lake

1999年1月~2000年12月对杭州西湖浮游植物群落进行了为期2年的逐月调查.结合以前的研究资料,着重分析了20世纪80年代先后采取的截污、疏浚、引水冲污等一系列治理富营养化措施所产生的长期生态效应.结果表明,大部分湖区浮游植物群落结构与治理前基本相同,仍以蓝藻占绝对优势.1980~2000年,浮游植物密度增加了55.4%.蓝藻种类趋于小型化,20年来西湖的富营养化仍在发展.西湖子湖之一小南湖区经一系列工程治理后,出现了大面积的沉水植物,水体透明度大大提高,藻量明显下降,水体富营养特征逐渐从浮游植物响应型向大型高等水生植物响应型转化.因此,建立和恢复以沉水植物为主的生态系统,是治理西湖富营养化的有效途径.

From Jan. 1999 to Dec. 2000, the phytoplankton communities of Hangzhou West Lake were investigated monthly for two years. Combined with the previous research data. The long-time ecological effect of eutrophication control measures such as damming, dredging, diluting etc. Used in the years 1980-2000 were analyzed. The results showed that the construction of the communities in most lake areas had unchanged with prior blue green algae, and the density of phytoplankton had increased 55.4% with blue green algae tending to scale down; while the lake eutrophication was still developing. One of the sub-lake, the Xiaonan lake area, after a series of control engineering had a large area of macrophytes, the transparency of the water was increased greatly and the density of algae was evidently decreased, and the water eutrophication character transformed gradually from phytoplankton type to macrophyte. Therefore, establishing and restoring the ecosystem mainly of macrophyte was the effective way to control the eutrophication of the West Lake.