Pattern changes of microbial communities in urban river affected by anthropogenic activities and their environmental driving mechanisms

The microbial community structure of sediments in the Bahe River Basin, China was studied using a high-throughput sequencing platform and PCR amplification to investigate the pattern changes in microbial communities in urban rivers affected by anthropogenic activities and their environmental driving mechanisms. The results demonstrated that the average total nitrogen and total phosphorus in the sediments were 524 and 734 mg/kg, respectively. The T, COD and NH4+-N of the water and the moisture content of the sediments has significantly impacted on the microbial community structure. Twenty microbial species with a relative abundance >1% in the sediments of the river were observed, accounting for 95-99% of the total microbial community. The primary species were Proteobacteria (13.86-69.14%), Firmicutes (1.45-58.33%), Chloroflexi (3.68-26.18%), Actinobacteria (2.7-21.51%), Acidobacteria (0.73-16.36%), Bacteroides (1.53-14.11%), and Thermodesulfobacteria (0.1-8.9%), accounting for over 90% of the total microbial community. At the class level, the primary species were gamma-proteobacteria, Alphaproteobacteria, Anaerolineae, Bacillus, Bacteroidota, Actinobacteriota, and Clostridia, accounting for over 70% of the total microbial community. Our results provide direct evidence for a link between microbial community structure and environment factors. This evidence demonstrates that sediment microorganisms can be applied to evaluate urban rivers pollution levels, which can provide a scientific basis for pollution control and management in the urban river affected by human activities.