School of Civil Engineering and Architecture, Chuzhou University, Chuzhou 239000, China.
School of Civil Engineering and Architecture, Chuzhou University, Chuzhou 239000, China.
Sci Total Environ. 2021 Nov 1;793:148475. doi: 10.1016/j.scitotenv.2021.148475. Epub 2021 Jun 19.
Sediment bacterial communities play a crucial role in the biogeochemical cycle of nutrient elements in urban river. However, the distribution of nitrogen cycle genes on bacterial communities in urban rivers sediments is largely unknown. Here, 16S rRNA amplicon sequencing was used to analyze the composition, co-occurrence patterns and nitrogen cycle process of bacterial communities in urban river sediments under the influence of different exogenous pollution. The results revealed that bacterial communities had significant spatial heterogeneity in river sediments of different polluted areas, and the input of different exogenous pollutants shaped the abundance and distribution of nitrogen cycle-related genes in the sediments. In addition, denitrification process played a leading role in the nitrogen cycle of river sediments, and the genes associated with the nitrification process were rarely observed in all samples. The important bacterial taxonomic biomarkers of nitrogen cycling-related genes screened by random forest algorithm were Synergistia, WS6_Dojkabacteria and Caldisericia. Meanwhile, different co-occurrence patterns observed in different types of polluted areas clarified the impact of environmental filtration and niche differentiation on bacterial communities. In conclusion, this study reveals the nitrogen cycle process and the distribution of related genes mediated by bacterial communities under the impact of different anthropogenic contamination, and provides novel insights for the assembly of bacterial communities in urban river sediments.
底栖细菌群落对于城市河流中营养元素的生物地球化学循环起着至关重要的作用。然而，目前对于城市河底沉积物中氮循环基因在细菌群落中的分布还知之甚少。在这里，我们使用 16S rRNA 扩增子测序技术，分析了不同外源污染影响下城市河底沉积物中细菌群落的组成、共生模式和氮循环过程。结果表明，不同污染区河底沉积物中的细菌群落具有显著的空间异质性，不同外源污染物的输入塑造了沉积物中氮循环相关基因的丰度和分布。此外，反硝化过程在河底沉积物的氮循环中起着主导作用，而所有样本中都很少观察到与硝化过程相关的基因。通过随机森林算法筛选出的氮循环相关基因的重要细菌分类生物标志物为协同菌属（Synergistia）、Dojkabacteria 属（WS6_Dojkabacteria）和考德里西亚菌属（Caldisericia）。同时，在不同类型污染区观察到的不同共生模式阐明了环境过滤和生态位分化对细菌群落的影响。总之，本研究揭示了不同人为污染影响下细菌群落介导的氮循环过程和相关基因的分布，为城市河底沉积物中细菌群落的组装提供了新的见解。
