The travelling particles: community dynamics of biofilms on microplastics transferred along a salinity gradient

Abstract Microplastics (MP), as novel substrata for microbial colonization within aquatic ecosystems, are a matter of growing concern due to their potential propagate foreign or invasive species across different environments. MP known harbour diversity microorganisms, yet little is understood the dynamics biofilms and capacity successfully displace these microorganisms ecosystems typically marked by steep salinity gradients. To address this, we performed an in situ sequential incubation experiment simulate transport from riverine coastal seawaters using synthetic (high-density polyethylene, HDPE tyre wear, TW) natural (Wood) substrata. Bacterial communities on incubated particles were compared each other well those surrounding waters, along gradient investigated. All differed significantly overall structure shaped ecological processes. While governed environmental selection, TW Wood dominated stochastic events dispersal drift. Upon transfer into seawaters, almost complete turnover was observed among communities. displaced minor proportion gradient, some comprised putatively pathogenic resistant taxa. Our findings present extensive assessment upon displacement systems, presenting new insights role vectors.