Evolution of microbial plastisphere from the river to the sea: the case of the Sarno river (Italy). Evolution of microbial plastisphere from the river to the sea: the case of the Sarno river (Italy)

Rivers are recognized as major vectors of plastic pollution to the sea. This study investigated microplastics (MP) and their associated microbial plastisphere in the Sarno river (Italy), its estuary and the nearby coastal area in January 2020. An integrated approach using Scanning Electron Microscopy (SEM), High Throughput Sequencing (HTS) and Fourier-Transformed Infrared Spectroscopy (FTIR) was used to characterize the collected MPs and their associated microbes. The three stations differed significantly for MP concentrations and microbial community composition and density. The prokaryotic plastisphere was markedly different from freshwater and marine sites, with representatives from only 9 taxa shared between the three sites, also different from those observed in other studies, suggesting that attachment to MP is also modulated by other environmental factors, such as salinity or quality and quality of organic matter.