The abundance and composition of nitrogen transformation-related microbes with certain environmental parameters for living conditions provide information about the nitrogen cycle in the Yangtze Estuary. The aim of this study was to explore the impacts of salinity on four N-related microbes and reveal the phylogenetic characteristics of microorganisms in the Yangtze Estuary ecosystem. A molecular biology method was used for the quantitation and identification of four microbes in the Yangtze River: ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA), denitrifying microbes (nirS-type), and anaerobic ammonia-oxidizing (anammox) bacteria. Sequence identification was performed on the levels of phylum, class, order, family, and genus, and the sequences were then matched to species. The results showed that the dominant species of AOA were crenarchaeote enrichment cultures, thaumarchaeote enrichment cultures, and Nitrosopumilus maritimus cultures, and the dominant AOB species were betaproteobacterium enrichment cultures and Nitrosomona sp. The denitrifying microbes were identified as the phylum Proteobacteria, classes Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria, and the species Thauera selenatis. The dominant species of the anammox bacteria was Candidatus Brocadia sp. In the estuarine sediments of the Yangtze River, the nirS gene abundance (1.31 × 107–9.50 × 108 copies g−1 sediments) was the highest among all the detected genes, and the abundance of bacterial amoA, archaeal amoA, and nirS was significantly correlated. Closely correlated with the abundance of the bacterial amoA gene, salinity was an important factor in promoting the abundance and restraining the community diversity of AOB. Moreover, the distribution of the AOB species exhibited regional patterns in the estuarine zone. The results indicated that salinity might promote abundance while limiting the diversity of AOB and that salinity might have reverse impacts on AOA. Denitrifying microbes, which showed a significant correlation with the other genes, were thought to interact with the other genes during nitrogen migration. The results also implied that AOA has a lower potential nitrification rate than AOB and that both the anammox and denitrification processes (defined by nirS gene) account for N2 production.

中文翻译：

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长江口四种与氮转化有关的微生物的丰度，多样性和分布模式以及盐度

与某些与生活环境有关的环境参数的氮转化相关微生物的丰富和组成为长江口的氮循环提供了信息。这项研究的目的是探讨盐度对四种氮相关微生物的影响，并揭示长江口生态系统中微生物的系统发育特征。分子生物学方法用于定量和鉴定长江中的四种微生物：氨氧化细菌（AOB），氨氧化古细菌（AOA），反硝化微生物（nirS型）和厌氧氨氧化（anammox ）细菌。在门，类别，顺序，科和属的水平上进行序列鉴定，然后将序列与物种匹配。结果表明，AOA的优势种为Crenarchaeote富集培养物，thaumarchaeote富集培养物和Nitrosopumilus maritimus培养物，而AOB的优势种为β变形杆菌富集培养物和Nitrosomona sp.。反硝化微生物被鉴定为Proteobacteria门，Alphaproteobacteria，Betaproteobacteria和Gammaproteobacteria以及Thauera selenatis种。厌氧细菌的优势种是假丝酵母。在检测到的所有基因中，长江口的nirS基因丰度最高（1.31×107–9.50×108份g-1沉积物），细菌amoA，古细菌amoA和nirS的丰度显着相关的。与细菌amoA基因的丰度紧密相关，盐度是促进AOB丰度和限制群落多样性的重要因素。此外，AOB物种的分布在河口带表现出区域性格局。结果表明，盐度可能会促进丰度，同时限制AOB的多样性，盐度可能会对AOA产生反向影响。反硝化微生物与其他基因具有显着相关性，被认为在氮迁移过程中与其他基因相互作用。该结果还暗示，AOA的潜在硝化速率低于AOB，并且厌氧消化和反硝化过程（由nirS基因定义）都占了N2的产生。AOB种类的分布在河口带表现出区域性格局。结果表明，盐度可能会促进丰度，同时限制AOB的多样性，盐度可能会对AOA产生反向影响。反硝化微生物与其他基因具有显着相关性，被认为在氮迁移过程中与其他基因相互作用。该结果还暗示，AOA的潜在硝化速率低于AOB，并且厌氧消化和反硝化过程（由nirS基因定义）都占了N2的产生。AOB种类的分布在河口带表现出区域性格局。结果表明，盐度可能会促进丰度，同时限制AOB的多样性，盐度可能会对AOA产生反向影响。反硝化微生物与其他基因具有显着相关性，被认为在氮迁移过程中与其他基因相互作用。该结果还暗示，AOA的潜在硝化速率低于AOB，并且厌氧消化和反硝化过程（由nirS基因定义）都占了N2的产生。被认为在氮迁移过程中与其他基因相互作用。该结果还暗示，AOA的潜在硝化速率低于AOB，并且厌氧消化和反硝化过程（由nirS基因定义）都占了N2的产生。被认为在氮迁移过程中与其他基因相互作用。该结果还暗示，AOA的潜在硝化速率低于AOB，并且厌氧消化和反硝化过程（由nirS基因定义）都占了N2的产生。