The coupled effect of sediment resuspension and microbiota on phosphorus release and transformation in a simulated aquatic ecosystem

Plant microbial involvement in phosphorus (P) release and transformation during resuspension events in bottom aquatic systems remains poorly understood. Laboratory experiments were used in this study to explore the release and transformation of P from sediments and the microbiota involved. Dissolved and labile P were ob-tained by high-resolution dialysis and the diffusive gradients in thin films (DGT) technique, respectively. The bacterial community was investigated using a scanning electron microscope and 16S rRNA high throughput sequencing technique. Finally, the diffusion fluxes dynamics of phosphorus were calculated using the DGT-induced fluxes in sediments and soils (DIFS) model. These results showed that sustained disturbance can bal-ance dissolved P concentrations in the resuspension layer (overlying water) and enhance the stability of P transformation and release processes. Notably, the bacterial community within the deeper sediment layer (Below 10 mm sediment depth) significantly influences P interception. Acidobacteria and Neobacteria were identified as the key bacterial genera responsible for phosphorus adsorption of plant roots at speeds of 150 rad/min (R150). In addition, as the sediment depths increased, a slower decrease in R curves fitted with the DIFS model, which indicated a continuous resupply process from solid phase to pore water, especially below R150. This study provides theoretical references for managing shallow lakes with frequent sediment resuspension.