Department of Hydrosciences, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China; MOE Key Laboratory of Surficial Geochemistry, Nanjing University, Nanjing 210023, China.
Department of Hydrosciences, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China; MOE Key Laboratory of Surficial Geochemistry, Nanjing University, Nanjing 210023, China.
Sci Total Environ. 2024 Jan 10;907:167926. doi: 10.1016/j.scitotenv.2023.167926. Epub 2023 Oct 19.
Exploring how nitrogen (N) cycling microbes interact in eutrophic lake sediments and how biogenic elements influence the nitrogen cycle is crucial for understanding biogeochemical cycles and nitrogen accumulation mechanisms. In this study, sediment samples were collected from various areas of Taihu Lake with different trophic conditions in all four seasons from 2015 to 2017. Using high-throughput sequencing and molecular ecological network analysis, we investigated the microbial interaction patterns and the role of nitrogen cycling in sediments from lakes with different trophic conditions. The results showed distinct structures of sediment microbial networks between lake areas with different trophic conditions. In the more eutrophic region, network indices indicate higher transfer efficiency of energy, material, and information, more significant competition, and weaker niche differentiation of the microbial community. The sedimentary environment in the moderately eutrophic area exhibited greater potential for denitrification, nitrification, and anammox compared to the mesotrophic area, but the inhibition between N functional microbes and limitations in N removal processes were also more likely to occur. The topological structure of the networks showed that the carbon (C), sulfur (S), and iron (Fe) cycles had a strong influence on the nitrogen cycle in both lake areas. In the moderately eutrophic lake area, C- and S-cycling functional bacteria facilitated a closed cycle of the coupled N fixation-nitrification-DNRA (dissimilatory nitrate reduction to ammonium) process and reduced N removal. In the mesotrophic lake area, C- and S-cycling functional bacteria promoted both N fixation and mineralization, and Fe-cycling functional bacteria coupled with denitrifiers enhanced the nitrogen removal process of products from nitrogen fixation and mineralization. This study improved the understanding of the nitrogen cycling mechanism in lake sediments under different trophic conditions.
探究富营养化湖泊沉积物中氮循环微生物的相互作用方式，以及生源要素如何影响氮循环，对于理解生物地球化学循环和氮积累机制至关重要。本研究于 2015 年至 2017 年，在四季从太湖不同富营养化区域采集沉积物样品。利用高通量测序和分子生态网络分析，我们研究了不同营养条件下湖泊沉积物中微生物相互作用模式和氮循环作用。结果表明，不同营养条件下湖泊沉积物微生物网络结构存在明显差异。在富营养化程度较高的区域，网络指标表明能量、物质和信息的传递效率更高，微生物群落的竞争更激烈，生态位分化较弱。与中营养化区域相比，中营养化区域的沉积物具有更强的反硝化、硝化和厌氧氨氧化潜力，但氮功能微生物之间的抑制作用和氮去除过程的限制也更有可能发生。网络拓扑结构表明，碳（C）、硫（S）和铁（Fe）循环对两个湖区的氮循环都有很强的影响。在中营养化湖区，C 循环和 S 循环功能细菌促进了固氮-硝化-DNRA（异化硝酸盐还原为铵）过程的封闭循环，减少了氮的去除。在中营养化湖区，C 循环和 S 循环功能细菌促进了氮固定和矿化，铁循环功能细菌与反硝化细菌耦合增强了氮固定和矿化产物的氮去除过程。本研究提高了对不同营养条件下湖泊沉积物氮循环机制的认识。
