Bacterial community variation caused by large-scale sand mining in the sediment of the Jialing River, China

To explore the influence of river large-scale sand mining activities on the microecology of subtropical rivers, a theoretical basis for the protection and restoration of river ecological environments is provided.In this study, high-throughput sequencing technology was used to analyze the structure, diversity and function of bacterial communities in the sediment of three types of rivers, the natural river of Jialing River, continuous large sand mining channel and terminated sand mining channel. In this study, high-throughput sequencing technology was used to analyze the structure, diversity and function of sediment bacterial communities in three types of river habitats: natural channels of the main stream of Jialing River, channels with continuous large-scale sand mining activities and channels with terminated sand mining activities, and the main limiting factors of sediment bacterial community changes were analyzed in combination with the physical and chemical properties of sediments. The results showed that there were significant differences in the physicochemical properties and bacterial community diversity of the sediments from the different sand mining environments (P<0.05). Large-scale sand mining activities significantly reduced the richness of sediment bacterial communities and the contents of TN, TOC, MC and S, among which TOC, MC and TN contents were the main driving forces affecting the structure and function of microbial communities. The dominant bacterial groups (relative abundance >5%) of sediment bacteria were Proteobacteria, chlorocurvula, Acidobacteria and actinobacteria, and their relative abundance was 46.86%, 10.56%, 9.89% and 4.21%, respectively, and Large-scale sand mining activities resulted in a significant increase in the relative abundance of Proteobacteria, Acidobacteria and Actinobacteria. However, the relative abundances of Chloroflexi and Planctomycetes were significantly reduced (P<0.05). In terms of the level 2 function of the sediment bacterial community, 19 genes, such as genes involved in global and outline metabolism, carbohydrate metabolism and amino acid metabolism, were active. Among them, large-scale sand mining induced significant changes in level 2 functions, such as energy metabolism, cofactor and vitamin metabolism, translation, lipid metabolism and metabolism, folding, classification and degradation (P<0.05). In conclusion, Continued large-scale sand mining activities lead to changes in the structure and function of sediment bacterial communities, which significantly impacts the stability of the ecosystem in the Jialing River Basin.