低温条件下人工湿地氨氧化微生物的群落结构特征

Community structure characteristics of ammonia-oxidizing microorganisms in constructed wetland at low temperature

为了解冬季低温条件下人工湿地沉积物的氨氧化潜力及其影响因素,以北京市汉石桥湿地自然保护区内的人工湿地为研究对象,测定了不同湿地单元沉积物的硝化潜势(PNR)及其相关功能基因的丰度。结果表明,沉积物的PNR较高,说明冬季人工湿地具有较高的硝化潜力。PNR从入水段到出水段呈现先增加后减少的趋势。通过建立硝化活性与功能微生物丰度的线性回归模型发现,氨氧化古菌(AOA,以AOA的amoA基因丰度表征)是影响硝化潜势的主要功能微生物。进一步构建硝化微生物丰度与环境因子的回归方程,发现影响AOA amoA基因丰度的主要环境因子是碳氮比(C/N),影响氨氧化细菌(AOB,以AOB的amoA基因丰度表征)丰度的主要环境因子是全氮(TN)含量。高通量测序测定人工湿地沉积物AOA和AOB的群落组成,各湿地单元检测到的AOB群落优势门为Proteobacteria,主要是β-Proteobacteria纲,AOA主要属于Crenarchaeota和Thaumarchaeota 2个门类。湿地4单元和5单元,1单元和6单元在AOB菌群群落组成上较为接近;湿地6单元、7单元、8单元在AOA菌群群落组成上较为接近。

To understand the potential nitrification rate of the constructed wetland sediments under low temperature conditions in winter and its influencing factors,the constructed wetland in the Hanshiqiao Wetland Nature Reserve in Beijing was selected as the research area,and the potential nitrification rate(PNR)and the abundance of their related functional genes were investigated.The results showed that the PNR of the sediment was higher,indicating that the constructed wetland had higher nitrification potential in winter.The PNR increased first and then decreased from the inlet section to the outlet section.By establishing a linear regression model of nitrification activity and functional microbial abundance,we found that ammonia-oxidizing archaea(AOA,characterized by the abundance of amoA gene in AOA)was the main functional microorganism affecting the nitrification potential.By further constructing the regression equation of microbial abundance and environmental factors,it was found that the main environmental factor affecting the abundance of AOA amoA gene was carbon-nitrogen ratio(C/N),and the main environmental factor affecting the abundance of ammonia-oxidizing bacteria(AOB,characterized by abundance of amoA gene in AOB)was total nitrogen(TN)content.High-throughput sequencing was used to determine the community composition of AOA and AOB in constructed wetland sediments.The dominant phylum of AOB community in each wetland unit was Proteobacteria,which was mainly composed ofβ-subdivision of Proteobacteria,and AOA mainly belonged to Crenarchaeota and Thaumarchaeota.In terms of community composition,for AOB,wetland units 4 and 5,1 and 6 were relatively similar in flora composition,for AOA,wetland units 6,7,8 were relatively close.