包气带反硝化菌的空间分布及其与环境因子的相关性分析——以潮白河冲洪积扇为例
Spatial distribution of denitrifying bacteria in the aerated zone and its correlation with environmental factors-- A case study of Chaobai River alluvial fan
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摘要: 包气带反硝化过程对地下水硝酸盐污染治理具有重要作用,其中反硝化菌的空间分布是影响反硝化过程关键因素。目前,还没有研究关注北京潮白河洪积扇区包气带土壤深度等理化性质对反硝化菌群组成和结构的影响。本研究采用高通量测序和分子生态网络技术对潮白河包气带剖面土壤细菌群落进行研究,通过Spearman非参数分析方法、冗余分析方法、随机森林分析方法和Mantel Test相关性分析方法,分析了环境因子与反硝化细菌多样性、反硝化菌结构和组成的相关性。结果显示,反硝化菌属相对丰度表现出一定规律:nirK>nirS>nosZ。nirS、nirK和nosZ基因主要在固氮菌属和根瘤菌属中表达,OTU关联网络显示的正向相关的边所占比例较高:nirS-97.47%;nosZ-90.77%;nirK-82.44%。nirS基因和nosZ基因下两个剖面的LEfSe分析存在差异。pH、氨氮含量、土壤深度和黏粒含量是影响反硝化细菌α多样性的主要因素;土壤深度、氧化还原电位(Eh)、土壤黏粒含量(Clay)和OM是影响反硝化菌群落结构的主要驱动因子。该研究初步揭示了潮白河冲洪积扇包气带反硝化菌随环境因子变化所产生的差异性分布,对研究包气带的反硝化过程具有重要参考意义。Abstract: The denitrification process in the inclusion zone plays an important role in groundwater nitrate pollution management, where the spatial distribution of denitrifying bacteria is a key factor affecting the denitrification process. Currently, no studies have focused on the effects of soil depth and other physicochemical properties on the composition and structure of denitrifying bacterial populations in the inclusion zone of the Chaobai River floodplain fan area in Beijing. In this study, we used high-throughput sequencing and molecular ecological network technology to study the soil bacterial community in the Chaobai River air inclusion zone profile and analyzed the correlation between environmental factors and denitrification bacteria diversity, denitrifying bacteria structure and composition by Spearman's non-parametric analysis method, redundancy analysis method, random forest analysis method and Mantel Test correlation analysis method. The results showed that the relative abundance of denitrifying bacteria genera showed a certain pattern: nirK>nirS>nosZ. nirS, nirK, and nosZ genes were mainly expressed in nitrogen-fixing bacteria and rhizobia genera, and the OTU association network showed a high proportion of positively correlated edges: nirS-97.47%; nosZ-90.77%; nirK-82.44%. There were differences in LEfSe analysis between the two profiles under the nirS and nosZ genes. pH, ammonia nitrogen content, soil depth, and mucilage content were the main factors affecting denitrification bacteria α diversity; soil depth, redox potential(Eh), soil mucilage content (Clay), and OM were the main drivers affecting denitrifying bacteria community structure. This study initially reveals the differential distribution of denitrifying bacteria in the alluvial floodplain fan of the Chaobai River in response to changes in environmental factors, which is of great reference significance for studying denitrification processes in the air-packing zone
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Key words:
- Vadose zone /
- denitrification /
- nitrite reduction gene /
- nitrous oxide reduction gene
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