Early microbial colonization study of daily-use plastics exposed to river water

In rivers, microorganisms colonize plastic surfaces, initiating processes that can lead to their microbial decomposition. Our study investigates the bacterial community composition and diversity on the surfaces of plastics used daily, such as polyethylene terephthalate (PET) and low-density polyethylene (LDPE), which were exposed to river water from the Aller and Fusche rivers. Glass was used for comparison purposes. 16s rRNA sequencing revealed that the type of surface and the native microbial community in the river water, including the water quality, significantly influenced biofilm community assembly. River water samples, especially from the Fusche site, supported the highest microbial richness, while plastic exhibited moderate diversity, and glass beads hosted the lowest richness and diversity. Proteobacteria and Bacteroidetes dominated across all samples, with notable enrichment of functionally relevant families such as Rhodobacteraceae and Comamonadaceae. Ecologically relevant genera such as Flavobacterium, Hydrogenophaga, Rhodoferax, Sediminibacterium, and Rhodobacter dominated across samples. Alpha diversity reflected the richness of taxa within each sample, while beta diversity revealed distinct clustering based on both plastic type and site, indicating the influence of ecological pressure and niche partitioning. These findings highlight the capacity of plastic surfaces to harbour diverse and specialised bacterial assemblages, with implications for biogeochemical cycling, pollutant interactions, and potential microbial degradation pathways. This work contributes to deciphering the ecological roles of biofilms in freshwater plastisphere micro-environments and underscores the importance of material-specific microbial dynamics in assessing environmental risks.