Environmental factors control microbial colonization of plastics in the North Sea

Large quantities of plastic enter the oceans each year providing extensive attachment surfaces for marine microbes yet understanding their interactions and colonization of plastic debris remains limited. We investigated microbial colonization of various plastic types (polyethylene, polystyrene, polyethylene-terephthalate, and nylon) in ex-situ incubation experiments. Plastic films, both UV-pretreated and untreated, were exposed to seawater from a coastal and an offshore location in the North Sea. 16S rRNA amplicon sequencing was employed to assess microbial community structures after 5, 10, 30, and 45 days of incubation. Our findings show the significant influence of time, seawater origin and plastic type on microbial community succession. We also identified several genera associated with hydrocarbon or plastic degradation potential as well as genera selecting for specific plastics such as Ketobacter and Microbacterium. Our results highlight potential role of microorganisms in plastic biodegradation and support the idea that microbial colonizers on marine plastics debris seemingly select distinct substrate types.