中文摘要：

生物酶对矿质元素的生物地球化学循环有重要作用，但酶对环境的敏感性导致其活性易受外界因素影响。很多研究关注了富营养化对沉积物酶活性的影响，但却鲜见水华生消过程对沉积物生物酶活性影响的报道。本研究以长江流域典型湖泊———巢湖为对象，于水华生消不同时段采集沉积物和水体样品，分析沉积物水解酶和氧化还原酶活性随时间的变化。结果表明，巢湖水华形成期为5月15日－6月20日，持续期为6月20日－9月5日，之后进入水华消亡期。除部分时段的碱性磷酸酶外，水华区沉积物的脲酶、过氧化氢酶、多酚氧化酶活性均高于非水华区，水华区环境因子变化大导致酶活性的影响因素多样化，而非水华区环境因子变化相对较小，2种水解酶活性主要受沉积物pH值和底物含量影响，而2种氧化还原酶活性受沉积物TOC含量影响显著。从水华生消过程看，水华区脲酶、碱性磷酸酶活性变化明显大于非水华区，过氧化氢酶和多酚氧化酶也呈现类似的变化趋势。本研究表明，水华及其生消过程对沉积物生物酶的活性有影响，但影响大小与酶的种类有关。

英文摘要：

Enzymes play important roles in the biogeochemical cycles of mineral elements .However , their activities are apt to be impacted due to their sensitivity to environmental changes .Many studies concern the effects of eutrophication on enzyme activities in sediment , yet less attention is paid to the effects of the outbreak and perishing of water bloom .In this study , water and sediment samples were taken during the processes of outbreak and perishing of water bloom in a typical lake in the Yangtze River basin （ i.e.the Chaohu Lake ） , and the changes of hydrolase and oxidoreductase activ-ities in sediment in these processes were analyzed .Results showed that the water bloom formed between May 15 and June 20, sustained from June 20 to September 5, and then began to perish.Except for the alkaline phosphatase in some periods , activities of the urease , catalase and polyphenol oxidase in the sediment in the water bloom region were higher than those in the non-bloom region .In the water bloom region , environmental factors varied significantly with the out-break and perishing of water bloom , and many factors would cause the change of enzyme activity in sediments .In the non-bloom region , however , environmental factors were of less variation .The activity of two hydrolases were affected by the pH value and enzyme substrate in sediment , while the activity of two oxidoreductases were significantly affected by the TOC in sediment .Activities of the urease and alkaline phosphatase in the water bloom region showed greater varia -tion than those in the non-bloom region during the water bloom period .Activities of the catalase and polyphenol oxidase showed similar trends .Results showed that the enzyme activities in sediment were affected by the outbreak and perishing of water bloom .But the effects are dependent on enzyme species .