Differential insights into the distribution characteristics of bacterial communities and their response to typical pollutants in the sediment and soil of large drinking water reservoir

In this study, a large drinking water reservoir (Fengshuba Reservoir) was chosen as a representative case, and the bacterial communities in the sediments and soils of Water-level fluctuating zone (WLFZ) as well as their responses to heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) were systematically investigated. The results indicated that the abundance and diversity of the bacterial community obviously changed with seasonal hydrological variations in sediments, and the absolute abundance and composition of bacteria community differed significantly between the sediment phase and soil phase. Bacteria with the ability to degrade pollutants rapidly proliferate and gain ascendancy in the soil phase, with Burkholderia-Caballeronia-Paraburkholderia (B-C-P) and Bradyrhizobium forming the core of the largest community. Furthermore, Co-occurrence network analysis indicated that a more stable bacterial community composition in the sediment phase. The community assembly pattern of bacteria in sediments exhibit a higher degree of stochasticity than that observed in soils of the WLFZ. Furthermore, the Spearman correlations found that the interaction between physicochemical factors, HMs, and PAHs with bacteria community was stronger in the soils of WLFZ. In total, the structural equation models indicated that PAHs were the main driver in altering the deterministic process of bacterial community in the sediment, while HMs and physicochemical factors had a greater effect on the bacteria community in the WLFZ. This study systematically revealed the differential characteristics of bacterial community and their response to typical pollutants between the sediments and soils of large drinking water reservoir.