Due to the shortage of water resources in the lower part of the Yellow River Basin, many plain reservoirs are constructed to divert and store the Yellow River as the main water source. The diversion-sinking-storage process in the Yellow River Diversion Reservoir produces characteristic hydrodynamic changes and rapid sediment deposition. Microbial communities play an important role in biogeochemical cycles of aquatic ecosystems and are essential for the degradation of pollutants in water. The main objective of this study is to investigate the impacts and changes on the diversity, function, and assembly mechanism of microbial communities under rapid sediment deposition in the Yellow River.
  The results showed that during rapid sediment deposition, different community structures formed between the water body and the sediments, and the variability between them increased with increasing water depth. Sediment was more closely associated with C, N, and S cycling processes, while water was more closely associated with light reactions. Along the direction of water flow, microbial community diversity, community composition, and function changed significantly. The microbial community was affected by both sedimentation and environmental factors. T, NH₄⁺-N and EC were the key environmental factors affecting the structure of microbial community. Under rapid sediment deposition, microbial community assembly was dominated by stochastic processes. Along the sedimentation direction, the heterogeneity between sediment microbial communities increased, and water microbial communities tended to homogenise among themselves. The study's results can provide a reference for exploring the mechanism of microbial community changes in reservoirs under the dynamic hydrological conditions of the Yellow River.