再生水补水对河流湿地香蒲根际细菌群落结构影响研究

以典型的再生水补水河流湿地为例,采用末端限制性片段长度多态性技术(T-RFLP)分析河道不同空间香蒲根际细菌群落结构差异,并借助单因素方差分析(one-way ANOVA)、Spearman等级相关分析和典范对应分析(CCA)方法解析麻峪湿地香蒲根际细菌群落结构空间差异特征的形成原因,以揭示再生水补水过程对河道湿地香蒲根际细菌群落的影响,并尝试找出空间差异形成的驱动因子.结果表明:随再生水干扰强度的增加,各类群细菌群落的丰富度、均匀度及多样性均呈现不同程度的降低趋势;其中γ-变形菌门(Gammaproteobacteria)、δ-变形菌门(Deltaproteobacteria)和绿弯菌门(Chloroflexi)、ε-变形菌门(Epsilonproteobacteria)和放线菌门(Actinobacteria)在再生水影响下均显著降低(P<0.05).Spearman等级相关分析显示pH值、DO(溶解氧)、TDS(总溶解固体)、ORP(氧化还原电位)、Sal(盐度)和NH₄⁺-N(氨氮)与植物根际细菌群落多样性空间演替紧密相关.CCA分析结果进一步表明再生水补水口的上游细菌群落与TN(总氮)、TOC(总有机碳)及重金属Cr、Ni、Cu具有密切关系,这可能与这些污染物累积效应有关;补水口附近植物根际细菌群落则因补水口再生水水质不同而具显著差异,其中第Ⅱa类群主要受到水质变量pH值影响较大,而第Ⅱb类群与T(温度)、ORP和NH₄⁺-N具有较高的相关性;补水口的下游细菌群落则因水体内源杂质及人为活动影响而同样与TOC及持久性痕量重金属生物循环密切相关.

Influence of reclaimed water on bacterial community structure of cattail rhizosphere from riverine wetland

Water reclamation and reuse have been actively promoted in Beijing, but the potential influences of reclaimed water on the microbial community structures are still poorly understood. Therefore, bacterial community structures in cattail rhizosphere between the samples of reclaimed water outfall and far from the reclaimed water outfall in the Mayu Wetland of Yongding River, Beijing were compared. Terminal restriction fragment length polymorphism (T-RFLP) was conducted to quantitatively detect the changes of bacterial community structures. Several statistical methods including one-way analysis of variance (ANOVA), spearman's correlation analysis and canonical correspondence analysis (CCA) were united to find out which were the key environmental factors to drive the bacterial community structure shifts. The result showed that microbial richness, evenness and diversity decreased with the increase of the reclaimed water interference intensity. The diversity of Gammaproteobacteria, Deltaproteobacteria, Chloroflexi, Epsilonproteobacteria and Actinobacteria were decreased significantly near the reclaimed water outfall. Spearman's correlation analysis indicated that pH, DO, TDS, ORP, Sal and NH₄⁺-N play an important role in the diversity spatial variation of plant rhizosphere microbial community. CCA indicated that TN, TOC, and Cr、Ni、Cu were significantly correlated with microbial communities structures of the upstream of reclaimed water outfall. Plant rhizosphere bacterial communities near the outfall were significantly different due to the reclaimed water quality difference. Group IIa and IIb were mainly affected by pH and T、ORP、NH₄⁺-N, respectively. While the bacterial communities in the downstream were also significantly correlated with TOC and some heavy metals due to water internal impurities and human activity influence.