溶解氧变化对底泥酶活性及微生物多样性的影响

采用室内静态实验考察了溶解氧变化对底泥酶活性影响,同时采用BIOLOG ECO微平板构造了不同溶解氧水平下底泥微生物多样性指数。结果表明:高溶解氧条件下,底泥多酚氧化酶及过氧化物酶活性显著高于缺氧条件及厌氧条件(P<0.01),脱氢酶活性高于背景值;厌氧条件下脱氢酶、脲酶及碱性磷酸酶活性显著高于高溶解氧组、缺氧组及背景值(P<0.05);缺氧条件下硝酸盐还原酶活性显著高于高溶解氧组及厌氧组(P<0.05);蛋白酶活性受溶解氧水平变化的影响较小。BIOLOG ECO微平板法分析表明,溶解氧变化对底泥微生物多样性有不同程度的负面影响,微生物多样性的降低程度从大到小依次为高溶解氧组>厌氧组>缺氧组。主成分分析结果表明:缺氧条件及厌氧条件下,底泥微生物对大分子有机物的利用出现不同程度的降低,相对地,高溶解氧条件下微生物对大分子有机物的利用程度呈现先下降后上升的趋势;高溶解氧组及缺氧组底泥微生物对碳水化合物利用程度升高,厌氧组对碳水化合物利用程度降低。总之,高溶解氧条件更有利于形成底泥有机物完整的代谢循环,提高大分子有机物的利用程度。

Effects of Variation of DO on the Enzyme Activity and Microbial Diversity in Sediments

Indoor static experiment was done to investigate the effect of different dissolved oxygen concentrations to the enzyme activity in sediments,and diversity indices for sediments microbial community were constructed based on reactions on BIOLOG ECO microplate.Results indicated that under the conditions of high dissolved oxygen,polyphenol oxidase and peroxidase activity were significantly higher than the groups of anaerobic condition and anoxic condition,and dehydrogenase activity was higher than the background value.With anaerobic conditions,dehydrogenase,urease and alkaline phosphatase activity were significantly higher than the groups of high dissolved oxygen condition,anoxic condition and background value.Under anoxic condition,nitrate reductase activity was significantly higher than the groups of high dissolved oxygen condition and anaerobic condition.Dissolved oxygen concentration had little influence on the protease activity.BIOLOG ECO experiments revealed that change of dissolved oxygen had different degrees of negative effects on sediment microbial diversity,with sequence of decreased degree of microbial diversity as saturated dissolved oxygen condition,anaerobic condition and anoxic condition.Principal component analysis demonstrated that under the anaerobic and anoxic condition,the use of macromolecular organic compounds were decreased,while that was rising trend after downward at first under high dissolved oxygen condition.Carbohydrates utilization degree under high dissolved oxygen and anoxic condition were increased,while there was decreased trend under anaerobic condition.It was more conducive to form a complete circulation of organic matter,and improved the utilization level of macromolecular organic matters under high dissolved oxygen condition.