Variation of Diversity and Activity of Ammonia-Oxidizing Bacteria Community in the Integrated Vertical-Flow Constructed Wetlands
复合垂直流湿地氨氧化菌种群结构及活性的空间分布

Abstract: The activity of ammonia-oxidizing bacteria (AOB) in different layers of Integrated vertical-flow constructed wetlands (IVCW) treating eutrophic scenic water was measured, and the diversity and spatial distribution of AOB community structure in IVCW was investigated using PCR-DGGE. The results indicated that because of the integrated influence of competition of plant rhizodeposition, heterotrophic bacteria, DO and ammonia concentration, there were significant spatial differences in the activity and diversity of AOB along the flow direction of wetland. The activity of AOB were 0.79mg?(kg?h)-1 (in NO3--N, the same below) near the surface of down-flow system in IVCW. From the surface of down-flow system to up-flow system, the activity of AOB decreased gradually, and slightly increased to 0.17mg?(kg ?h)-1near the surface of up-flow system. The spatial variation of diversity of AOB showed similar change trend with the activity in IVCW and the diversity index in down-flow system (1.92) were higher than those in up-flow system (1.65). Most of AOB were belong to oligotrophic bacterium in IVCW, and the population of ammonia-oxidizing bacteria showed a higher percentage of Nitrosomonas-like sequences from the wetland samples. Uncultured beta proteobacterium, Comamonas sp., Nitrosomonas oligotropha were also detected. The variation of the AOB community demonstrated spatial pattern in IVCW, which might be related to different wetland environment.