School of Civil Engineering and Architecture, Chuzhou University, Chuzhou, 239000, China.
School of Civil Engineering and Architecture, Chuzhou University, Chuzhou, 239000, China.
Water Res. 2020 Oct 1;184:116089. doi: 10.1016/j.watres.2020.116089. Epub 2020 Jul 4.
Aquatic bacterial communities play an important role in biogeochemical cycling in river ecosystems; however, knowledge of the linkages between bacterial communities and dissolved organic matter (DOM) in urban rivers is limited. Here, 16S rRNA amplicon sequencing and parallel factor (PARAFAC) modeling of excitation-emission fluorescence spectroscopy were used to analyze the compositions, co-occurrence patterns, and interactions with chromophoric DOM (CDOM) of bacterial communities in urban river water samples influenced by different human activities. The results revealed that two protein-like components accounted for 65.2 ± 9.56% of the total variability in all three fluorescence components, which suggests that CDOM in urban rivers is mainly a microbial source. In addition to pH and DO, CDOM is also an important factor affecting bacterial community structure, and the main classes (Gammaproteobacteria and Clostridia) and genera (Limnohabitans and Alpinimonas) showed strong positive correlations with terrestrial humic-like C1 and tryptophan-like C2, respectively. When autotrophic and heterotrophic bacteria coexist in urban rivers, the production and degradation of CDOM will occur simultaneously. Furthermore, the riverine bacterial co-occurrence network had a nonrandom modular structure, which was mainly driven by classification correlation and bacterial function. The high abundance of genes related to xenobiotic metabolism, carbon metabolism and nitrogen metabolism in the urban river indicated that anthropogenic activity may be the dominant selective force altering the bacterial communities. Overall, our results provide a novel view for the assembly of bacterial communities in urban river ecosystems under the influence of different human activities.
水生细菌群落在河流生态系统的生物地球化学循环中起着重要作用；然而，关于城市河流中细菌群落与溶解有机物质（DOM）之间的联系的知识是有限的。在这里，我们使用 16S rRNA 扩增子测序和平行因子（PARAFAC）模型对激发-发射荧光光谱进行分析，以研究受不同人类活动影响的城市河流水样中细菌群落的组成、共现模式及其与发色 DOM（CDOM）的相互作用。结果表明，两种蛋白质样成分占所有三个荧光成分总可变性的 65.2±9.56%，这表明城市河流中的 CDOM 主要来自微生物源。除 pH 和 DO 外，CDOM 也是影响细菌群落结构的重要因素，主要类群（γ变形菌纲和梭菌纲）和属（Limnohabitans 和 Alpinimonas）分别与陆源腐殖质样 C1 和色氨酸样 C2 呈强烈正相关。当自养细菌和异养细菌共存于城市河流中时，CDOM 的产生和降解将同时发生。此外，河流水细菌共现网络具有非随机模块结构，主要由分类相关和细菌功能驱动。城市河流中高丰度的与外来化合物代谢、碳代谢和氮代谢相关的基因表明，人为活动可能是改变细菌群落的主要选择压力。总的来说，我们的研究结果为不同人类活动影响下城市河流生态系统中细菌群落的组装提供了新的视角。
