Comparison of the Microbial Communities Affected by Different Environmental Factors in a Polluted River

Abstract

Understanding how bacterial communities adapt to different environmental factors provides a scientific basis for developing and utilizing microbial resources in rivers. This study investigated the changes in the microbial communities of water and mud samples from two sites of an urban river (GH: Gonghe Village and YC: Yanchuan). Analysis of the water samples showed that site GH had higher concentrations of ammonium, total nitrogen, Mn, and Ni than site YC. High-throughput sequencing was used to analyze the community composition of the samples. The results showed that the dominant phyla were Proteobacteria, Bacteroidete, Actinobacteria, and Chloroflexi. The alpha diversity of the microbial community in the mud samples was higher than in the water samples. Moreover, the relative abundance of the dominant genus varied a lot between the samples, with the highest relative abundance of Arcobacter and Vibrio found in the water samples at site GH in January and October, respectively. The correlation analysis showed that pH, TN, manganese, and fluoride were the main environmental factors that affected the composition and structure of the microbial communities. The phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis showed that species associated with nitrogen metabolism differed between the sampling sites. In addition, potential pathogens, such as Vibrio and Arcobacter, which may pose potential risks to the environment and human health, were found in the samples.