Dynamic succession and biodegradation potential of microplastic prokaryotic microbial communities in the Pearl River estuary

Microplastics (MPs), as emerging pollutants, exhibit poorly understood dynamic characteristics and ecological effects of surface microbial communities in-situ, particularly regarding long-term succession patterns in estuarine environments. Through a 35-day in-situ experiment and multiple sampling in the Pearl River Estuary, combined with 16S rRNA gene sequencing and multidimensional ecological analyses, this study systematically revealed the temporal succession patterns and driving mechanisms of prokaryotic microbial communities on microplastics (polylactic acid, polypropylene, polystyrene) and natural particles (wood, stone, glass beads). Key findings include: (1) Microplastic surfaces exhibited significant substrate specificity: Bacillota and Bacteroidota rapidly colonized during short-term exposure (1 day), with alpha diversity significantly higher than natural particles. (2) Long-term exposure (35 days) reduced alpha diversity, while beta diversity analysis indicated enhanced heterogeneity, suggesting selective enrichment of functional taxa (e.g., Campylobacterota, Desulfobacterota). (3) Biomarker analysis confirmed the preferential enrichment of Campylobacterota on microplastics, whose metabolic traits may contribute to plastic degradation, providing potential targets for bioremediation. Campylobacterota enrichment suggests biodegradation potential, particularly for PLA. Inert PP/PS accumulate homogenized communities, heightening ecological risks. These findings advance the understanding of microplastic-microbe interactions and offer a theoretical foundation for ecological risk assessment and bioremediation strategies.