Changes and drivers of bacterioplankton communities within plain river networks during the rainy season (high inflow event): simulation of the water level using the MIKE11 model

Unlike natural rivers, the microbial response mechanisms in human-dominated plain river networks remain poorly understood. These densely populated aquatic ecosystems, under intense anthropogenic influence, face dual pressures from climate change and landscape alteration. Their fragile hydrodynamics increase ecological vulnerability during the rainy season. Focusing on the Plum rain season, this study reveals that after the rainfall, community diversity significantly decreases, the contribution of rare taxa reduces, and bacterioplankton communities were no longer tightly linked. Combining MIKE11 modeling with multi-source environmental data, the study clarified the decisive role of water chemistry parameters in Cyanobacteria community shifts and validated the applicability of model data in ecological process research. These findings advance understanding of microbial adaptation in human-disturbed river networks and support ecosystem health assessment. The model-data fusion analysis method established in this study provides a technical framework for similar water ecosystem research.