New insights into the microbial succession and health risks of atmospheric plastispheres

Atmospheric microplastics serve as unique microbial niches, facilitating the formation of plastispheres. However, their microbial succession dynamics and associated health risks remain poorly characterized. To address these critical knowledge gaps, this study employed a two-month outdoor in-situ cultivation experiment, focusing on comparing bacterial colonization patterns on microplastics, natural and non-plastic substrates. Plastic-associated communities initially displayed polymer-specific colonization traits. Over time, these communities gradually converged, forming highly similar compositions. Functionally, the relative abundance of chemoheterotrophic pathways declined over time, while the proportion of light-dependent processes increased notably. Seven pathogenic species were specifically enriched on plastic substrates, of which four were detected only in later stages, indicating potential pathogen accumulation during biofilm maturation. Despite a decrease in the relative abundance of pathogens, the protective biofilm microenvironment may sustain their transmission risks. This study highlights the unique role of atmospheric microplastics as bacterial carriers, elucidating key aspects of their succession dynamics and health implications, highlighting the adaptive role of photoautotrophy under atmospheric stressors. It provides important insights for in-depth understanding of the environmental and health effects of atmospheric microplastics.