Functional response of bacterial communities in surface sediments of qingshitan reservoir to anthropogenic disturbance

Abstract

This study investigated the bacterial composition in surface sediments (0–5 cm) of Qingshitan Reservoir to elucidate their ecosystem functions in response to anthropogenic disturbances. Samples were collected in July 2023 from eight ecological points representing varying disturbance levels. High-throughput sequencing revealed significant variations in bacterial community structure. Sediments from the upstream cage aquaculture area (heavily disturbed) exhibited the highest bacterial richness, diversity, and evenness, while midstream and downstream areas (lightly disturbed) showed reduced diversity and uneven community structures. The dominant bacterial phyla included Firmicutes, Proteobacteria, Actinobacteriota, and Bacteroidota, with the most abundant genera being Lactobacillus, Escherichia-Shigella, Staphylococcus, Corynebacterium, and Brevibacterium.Functional predictions using PICRUSt2 indicated robust metabolic activity across all areas, particularly in amino acid metabolism within the cage aquaculture region. FAPROTAX analysis highlighted enhanced nitrate reduction in disturbed areas, suggesting a potential role in mitigating eutrophication through nitrogen cycling regulation. Additionally, BugBase identified elevated proportions of potentially pathogenic bacteria in upstream cage aquaculture and midstream residential areas, underscoring the need for targeted ecological risk management.These findings provide critical insights into the microbial ecology of Qingshitan Reservoir and its response to anthropogenic pressures, offering a scientific foundation for improving water resource utilization and ecological conservation efforts.