Niu Lihua, Xie Xudong, Li Yi, Hu Qing, Wang Chao, Zhang Wenlong, Zhang Huanjun, Wang Longfei
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, PR China.
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, PR China.
Sci Total Environ. 2022 Feb 1;806(Pt 3):151210. doi: 10.1016/j.scitotenv.2021.151210. Epub 2021 Oct 29.
Increasing attention has been focused on the diminishing health of coastal ecosystems. Understanding the effects of eutrophication on tidal flat ecosystems is beneficial for the restoration and management of coastal ecosystems. However, previous studies did not consider the effects of nitrogen on the structure and function of bacterial and archaeal communities in longitudinal and vertical profiles. Here, the diversity, composition, assembly mechanism, and potential metabolic function of the bacterial and archaeal communities were studied in two longitudinal tidal sections at different eutrophic levels. Nitrogen and salinity were the critical factors that influenced the bacterial and archaeal community composition using canonical correspondence and multivariate regression tree analyses. For the bacterial community, the higher nitrogen loading in tidal mudflats resulted in the convergence of diversity and structure in the longitudinal profile of bacteria, but divergence was detected in the vertical profile. For archaea, the diversity tended to be convergent in longitudinal and vertical profiles in the higher nitrogen area, but the change of structure was similar to that of bacteria. Besides the homogeneous processes influenced by salinity, the assembly process of the bacterial community was mainly influenced by heterogeneous selection (34.8%) and that of archaea by dispersal limitation (19.5%). However, the bacterial and archaeal communities in the higher nitrogen section presented more of an influence of heterogeneous selection (respectively, 39 and 5.6%) than that of the lower nitrogen section (respectively, 10 and 0.2%). Structural equation modeling indicated that nitrogen may have inhibited the effects of the bacterial community on nitrogen turnover in nitrogen-rich anoxic sediment environments, but may have strengthened the effect of the archaeal community on carbon metabolism compared to bacteria. This work deepens our understanding of the responses of bacterial and archaeal community structure and potential function to nitrogen pollution in tidal mudflats.
沿海生态系统健康状况的恶化日益受到关注。了解富营养化对潮滩生态系统的影响，有助于沿海生态系统的恢复和管理。然而，以往的研究未考虑氮对纵向和垂直剖面中细菌和古菌群落结构及功能的影响。在此，我们研究了不同富营养化水平的两个纵向潮段中细菌和古菌群落的多样性、组成、组装机制及潜在代谢功能。通过典范对应分析和多元回归树分析发现，氮和盐度是影响细菌和古菌群落组成的关键因素。对于细菌群落，潮滩中较高的氮负荷导致细菌纵向剖面的多样性和结构趋同，但在垂直剖面中则出现分化。对于古菌，在高氮区域，其多样性在纵向和垂直剖面中趋于趋同，但其结构变化与细菌相似。除了受盐度影响的均质过程外，细菌群落的组装过程主要受异质性选择（34.8%）影响，古菌群落的组装过程主要受扩散限制（19.5%）影响。然而，高氮剖面中的细菌和古菌群落比低氮剖面中的群落受异质性选择的影响更大（分别为39%和5.6%，低氮剖面分别为10%和0.2%）。结构方程模型表明，在富氮缺氧的沉积物环境中，氮可能抑制了细菌群落对氮周转的影响，但与细菌相比，可能增强了古菌群落对碳代谢的影响。这项工作加深了我们对潮滩中细菌和古菌群落结构及潜在功能对氮污染响应的理解。
