16S rRNA gene sequence analysis of the microbial community on microplastic samples from the North Atlantic and Great Pacific Garbage Patches

The exponential increase in plastic production has led to their accumulation in the environment, particularly in oceans, polluting these environments from the shore to the open ocean and even sea ice in the pole regions. Microbial communities were compared on plastic particles, known as "Plastisphere", collected from the Atlantic and Pacific ocean gyres in the Summer of 2019 and subsequently inspected for potential plastic degraders. A 16S rRNA amplicon sequencing approach was applied to decipher differences and similarities in colonization behaviour between these two gyres. Polyethylene (PE) and polypropylene (PP) plastic samples were retrieved and investigated. We found that microbes differed significantly between the two oceans and identified thirty-two differentially abundant taxa at the class level. Proteobacteria, Cyanobacteria and Bacteroidota were the most prominent relative abundant phyla in the two oceans. Finally, according to the current literature, we found 40 genera documented as potential plastic degraders. This study highlights the importance of the biogeographical location with respect to microbial colonization patterns of marine plastic debris, differing even in the open oceans. Furthermore, the wide distribution of potential plastic-degrading bacteria was shown. Key words: Plastisphere, microbial communities, plastic degraders.