Coastal rest during the COVID-19 pandemic enhances microbial community stability and metabolic potential in a subterranean estuary.

This study examines a subterranean estuary seepage face in China's Sanggou Bay by comparing environmental parameters and microbiome data before and after the COVID-19 lockdown, in order to reveal the regulatory mechanisms of coastal resting on microbial community stability and biogeochemical functions. The results revealed that reduced human activities significantly decreased sediment nutrient loading and shifted organic matter sources from terrestrial- to marine-dominated. This environmental restructuring drove profound microbial community reorganization: while α-diversity indices declined, the relative abundance of core species increased, with marked enhancements in community stability and metabolic efficiency, particularly in pathways related to amino acid metabolism, carbohydrate metabolism, and biogeochemical cycling. The study confirms that a coastal rest period can enhance ecosystem resilience by reducing anthropogenic disturbance, optimizing resource allocation, and activating microbial functional plasticity. These findings suggest that rest periods may represent a potential strategy for supporting ecosystem resilience and sustainability.