Detritus-Attached Microbial Networks as Early Warning Indicators of Sediment Ecosystem Resilience in a Macrophyte-Dominated Shallow Lake

Understanding the regulation of sediment ecosystem resilience by detritus–microbe interactions is crucial for shallow lake management. We examined the coupling among the detritus composition, attached microbial community structure, and network characteristics in Baiyangdian Lake to identify microbial early warning indicators of sediment resilience. The settling detritus was mainly derived from endogenous aquatic plants, which are rich in carbon, nitrogen, and phosphorus, with organic carbon accounting for over 90% in swamp zones. The α-diversity and composition of detritus-attached microbes varied significantly across seasons and habitats, dominated by Proteobacteria and Bacteroidota. The swamp area in summer exhibited the highest complexity and robustness (robustness = 0.490), with keystone taxa belonging to Proteobacteria, Chloroflexi, Actinobacteriota, and Patescibacteria. Detritus composition significantly influenced microbial assembly, with organic carbon correlated with Bacteroidota and Cyanobacteria (P < 0.05). The association among network complexity, stability, and keystone taxa demonstrates that network architecture underpins sediment ecosystem resilience. Spatial variations in microbial functional traits and key taxa reflected differences in disturbance intensity and recovery potential, providing sensitive, quantifiable early warning indicators of resilience loss. We introduce a process-oriented approach connecting detritus composition, microbial networks, and species-mediated mechanisms of sediment ecosystem resilience, offering a novel insight into the diagnosis and management of shallow lake sediment stability.