Distinct Assembly Mechanisms and Pathogenic Risks of the Plastisphere Microbiome in a Freshwater Lake: Evidence from Baiyangdian Wetland

Abstract

The plastisphere, a novel microbial ecosystem colonizing plastic surfaces, has attracted scientific interest due to its unique physicochemical properties supporting specialized microbial colonization. This study addresses the knowledge gap regarding microbial composition, functionality, and assembly mechanisms within Baiyangdian Lake's plastisphere through comprehensive analysis of microplastic samples from eight representative sites. Utilizing 16S rRNA and ITS high-throughput sequencing, we identified substantial divergence between plastisphere and surrounding water communities, with distinctive species accounting for 96.3% of bacterial and 95.4% of fungal populations. βNTI analysis revealed contrasting assembly mechanisms: plastisphere bacterial communities were predominantly governed by stochastic processes (56.94% dispersal limitation), while water communities followed homogeneous dispersal patterns (62.15%). Fungal assembly mirrored bacterial dynamics in the plastisphere. Functional profiling indicated enhanced organic degradation and nitrogen denitrification capacities in plastisphere microbiota compared to aquatic counterparts. Crucially, we detected elevated abundance of human pathogens within plastisphere communities, suggesting microplastics may act as reservoirs for pathogenic species dispersion. These findings highlight the plastisphere's ecological significance and potential environmental risks in freshwater ecosystems.

Keywords: Plastisphere, Microplastic Pollution, Ecological risk, microbial community assembly, Freshwater wetland