Description:
Microbial colonization and biofilm formation associated with microplastics (MPs) have recently attracted wide attention. However, little is known about the effect of MP shapes, aging states, and different exposed habitats on biofilm formation and associated microbial community characteristics. To obtain a comprehensive understanding, polypropylene MPs of different shapes and aging states were selected as attachment substrates and exposed to different aquatic habitats (marine, estuary, and river). The results showed that the aging process could cause cracks and small wrinkles and increase the roughness on the surface of MPs. The biofilm contents, attached-bacterial OTU numbers, and α diversities increased with exposure time. MP shapes can affect microbial attachment but have no significant effect on microbial community characteristics. The biofilm content and α diversity of MPs in the river were significantly higher than those in the marine and estuary habitats, and temperature and salinity were primary factors affecting microbial colonization. Bacterial communities in MP-attached biofilms were significantly different from those in surrounding water. Microorganisms tend to adhere to aged MPs, and especially, genes related to human pathogens were significantly expressed on aged MPs, suggesting a potential ecological and health risk of aged MPs in aquatic ecosystems. Our results showed that aging states and habitats have an important influence on microbial colonization of MPs, and the weathering process can accelerate biofilm formation on MPs