复合垂直流人工湿地污染物去除及微生物群落结构的PCR-DGGE分析

采用复合垂直流人工湿地净化富营养化景观水,考察了湿地系统中ρ(CODCr),ρ(TN),ρ(NH4 -N),ρ(TP)和ρ(DO)以及pH的沿程变化,并采用PCR-DGGE技术分析了湿地系统中微生物群落结构垂直分布及组成的多样性.结果表明:从下行池到上行池,ρ(CODCr),ρ(TN),ρ(NH4 -N),ρ(TP),ρ(DO)和pH沿水流方向逐渐下降,上行池末端出水ρ(DO)略有回升,污染物的去除主要发生在下行池;由于湿地系统中环境条件和营养水平的变化,在湿地系统的不同位置微生物种群存在共同种属和各自的特异种属;下行池表层微生物多样性指数最高,上行池各样品间的相似性较好.从下行池到上行池,微生物群落的多样性降低,群落结构间的相似性逐渐增大.植物供氧、残体累积以及根际效应有助于提高湿地表层微生物的多样性.

Pollutants Removal and Analysis of Structure Changes of Microbial Community in Integrated Vertical-Flow Constructed Wetland

The changes of COD_Cr, TN, NH₄⁺-N, TP and DO mass concentrations and pH of different layers in integrated vertical-flow constructed wetland (IVCW)treating eutrophic scenic water were measured, and the composition and diversity of bacteria community in IVCW was investigated by PCR-DGGE. The results showed that from down-flow system to up-flow system the contaminants and DO, pH decreased along the direction of water flow in IVCW, and the effluent DO mass concentration increased a little in up-flow system, and contaminants removal mainly happened in down-flow system in constructed wetland. There existed some common kinds of microorganisms and specific microorganisms in different layers in constructed wetland because of the changes of environmental factors and nutrient levels. Thediversity of bacteria community was the highest in the upper layer of down-flow system, and the similarity in down-flow system was higher than that in up-flow system. From down-flow system to up-flow system, the diversity of bacteria community decreased and the structure similarity gradually increased. The highercomplexity of the bacteria community in upper layer of constructed wetland may be supported by plant oxygenation, rhizodeposition and litter accumulation.