Dynamics of phytoplankton and water quality with control of cyanobacterial bloom in Lake Xuanwu,Nanjing

玄武湖是典型的城市富营养化湖泊,2005年夏季暴发了大面积微囊藻水华,其后以粘土法为主,对微囊藻水华进行了应急治理。为了解应急治理后玄武湖水生态状况的变化,通过分析治理后浮游植物种类和数量变化以及重要理化指标的变化,探讨应急治理对湖水水质和浮游植物群落的影响。通过对比治理前和水华暴发期的监测数据,发现治理后浮游植物数量减少,种类增多;湖水总磷和叶绿素a的浓度都明显降低;水体透明度大幅提高,湖水总氮浓度随浮游植物的密度和菹草的生长而出现波动。;Lake Xuanwu is a typical urhan eutrophic lake. Microcystis blcxm broke out in a large area of Lake Xuanwu in the sum-mer of 2005. The main method used to control the Microcystis bloom was the application of modified clay. In order to discover thechanges of the water ecological situation, the following tests were performed; inquiry into the changes of the quality of water andphytoplankton after the treatment, the analysis to the type and quantity of phytoplankton and physico-chemical indexes.The resultsshow; the amount of phytoplankton reduced, while the species increased after the treatment, the concentration of Chl. a and TP re-duced, with a substantial increase in SD, the concentration of TN was undulatory with phytoplankton density and Potarru}geton cris-pus growth.