中文摘要：

2009年夏季三峡水库支流小江回水区局部水域爆发水华,在水华爆发期的5月29日和6月18日开展了水华原生动物采样调查,分析了群落变动特征及其与水环境、水华藻类的关系。结果表明,水华均以蓝藻为主,其中5月的优势种类为水华鱼腥藻（Anabaena aquae）,6月的优势种类为微囊藻（Microcystis）,其次是浮游鱼腥藻（Anabaena planctonica）和小环藻（Cyclotella）;5月和6月的总磷、磷酸盐、叶绿素a含量、溶解氧、水温与pH等差异显著（P〈0.05）;5月鉴定出2种肉足虫,6月为10种肉足虫和5种纤毛虫;原生动物平均密度分别为200个/L和970个/L。冗余分析结果显示,与原生动物密度显著相关的水环境因子为总磷（TP）和溶解氧（DO）,浮游植物密度因子为浮游鱼腥藻和微囊藻。

英文摘要：

In the summer of 2009, water bloom occurred in the local water of Xiaojiang River backwater area of Three Gorges Reservoir. In this paper, during the algal bloom period, characteristics of protozoan community were studied in May 29th and June 18th, respectively. Their relationships with the water environment, water bloom algae were also been analyzed. Our results indicated that the dominant algae was cyanobacteria, and the bloom species were Anabaena aquae in May, but Microcystis, Anabaena planctonica and CycloteUa in June. The significant differ- ences between May and June were found in the total phosphorus, phosphate, chlorophyll a, dissolved oxygen, tem- perature and pH （P 〈0.05）. The protozoan species number in May and June was 2 and 15, respectively. The av- erage protozoan density in June was 970 ind./L, which was more than that （200 ind./L） in May. Redundancy analyses showed that the water environmental factors significantly affecting the densities of protozoa species were TP and DO, and the densities of protozoa correlated significantly with Anabaena planctonica and Microcystis densities.