长江中下游湖泊沉积物酶活性及其与富营养化的关系

Enzyme Activity in Sediments and Its Relation with Eutrophication in the Lakes along the Yangtze River

为揭示富营养化湖泊沉积物营养物分解合成过程的生物化学机制,研究了长江中下游6个浅水湖泊沉积物氮、磷、有机质和铵氮含量,水解酶、氧化还原酶活性,微生物种类与数量及之间的关系.结果表明:大通湖、珊珀湖、赛城湖和军山湖等养殖型湖泊,污染严重,其沉积物脲酶活性明显高于污染程度轻的大型湖泊鄱阳湖和洞庭湖,且与沉积物总氮(TN)、有机质(OM)含量呈极显著正相关(r=885,P<0.01;r=0.900,P<0.01);沉积物碱性磷酸酶(APA)活性与总磷(TP)含量呈极显著正相关(r=0.986,P<0.01).湖泊沉积物过氧化氢酶、多酚氧化酶与过氧化物酶活性变化趋势相近,分布状况与湖泊污染程度、人类活动干扰程度等紧密相连.湖泊沉积物微生物以细菌为主,放线菌次之,真菌最少.各湖泊氨化细菌数量差异较小,而反硝化细菌数量差异较大,反硝化细菌可能是导致该区域湖泊沉积物氮素累积的重要生物指示因子,可以作为反映湖泊富营养化程度的生物指示因子.

To reveal the biochemical mechanism of decomposition and synthesis of the nutrients in eutrophic lakes,the relationships among the contents of nitrogen,phosphorus,organic matter and ammonium nitrogen,the activity of hydrolase and oxidoreductase,and the amounts of different microorganisms were studied in six shallow lakes along the Yangtze River.The results showed that 1） in the lakes seriously polluted by farming activities,such as the Datong Lake,Shanpo Lake and Saicheng Lake,the urease activity in sediments was significantly higher than that in the lightly polluted large lakes,such as the Poyang Lake and Dongting Lake.And it showed significantly positive correlation with total nitrgen（TN） and orgnic matter（OM） in sediments（r=885,P0.01;r=0.900,P0.01,respectively）.And alkaline phosphatase also showed a positive correlation with total phosphorus（TP）（r=0.986,P0.01）;2） the changing trends of the activities of catalase,polyphenol oxidase and peroxidase were similar in lake sediments.And their distribution had a close relation with the degree of pollution and human activities;3） among the microoganisms in lake sediments,bacteria were dominant,actinomycetes were next and fungi were the least.There was little discrepancy of the number of ammonium bacteria in all the lakes,while the number of denitrifying bacteria was quite different.So,denitrifying bacteria might be an important bio-indicator factor which could reflect whether nitrogen accumulated or not in the lake sediments,and also reflect the degree of eutrophication.