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，关于城市河流细菌群落与溶解性有机物（DOM）之间联系的知识是有限的。在此，使用激发发射荧光光谱的16S rRNA扩增子测序和并行因子（PARAFAC）建模来分析城市河流水样中细菌群落的组成，共现模式以及与发色DOM（CDOM）的相互作用对不同影响的影响。人类活动。结果显示，两种蛋白质样成分占所有三个荧光成分总变异性的65.2±9.56％，这表明城市河流中的CDOM主要是微生物来源。除了pH和DOγ变形杆菌和梭状芽孢杆菌和属（Limnohabitans和Alpinimonas）分别与地面腐殖质样C1和色氨酸样C2呈强正相关。当自养细菌和异养细菌在城市河流中共存时，CDOM的产生和降解将同时发生。此外，河道细菌共生网络具有非随机的模块化结构，主要由分类相关性和细菌功能驱动。城市河流中与异种生物代谢，碳代谢和氮代谢相关的基因高度丰富，表明人为活动可能是改变细菌群落的主要选择力。总体而言，我们的结果为在不同人类活动影响下城市河流生态系统中细菌群落的聚集提供了新颖的观点。