Life in the “Plastisphere”: Microbial Communities on Plastic Marine Debris

TLDR

Plastics are the most abundant marine debris, persist longer than natural substrates, and their hydrophobic surfaces promote microbial colonization, yet their influence on open ocean microbial communities remains poorly understood. The study used SEM and next‑generation sequencing on North Atlantic plastic debris to characterize its attached microbial communities. The Plastisphere harbors diverse heterotrophs, autotrophs, predators, symbionts, hydrocarbon‑degrading bacteria, and potential pathogens, shows evidence of active polymer hydrolysis, and differs from surrounding water, indicating plastic as a novel ecological habitat.

Abstract

Plastics are the most abundant form of marine debris, with global production rising and documented impacts in some marine environments, but the influence of plastic on open ocean ecosystems is poorly understood, particularly for microbial communities. Plastic marine debris (PMD) collected at multiple locations in the North Atlantic was analyzed with scanning electron microscopy (SEM) and next-generation sequencing to characterize the attached microbial communities. We unveiled a diverse microbial community of heterotrophs, autotrophs, predators, and symbionts, a community we refer to as the "Plastisphere". Pits visualized in the PMD surface conformed to bacterial shapes suggesting active hydrolysis of the hydrocarbon polymer. Small-subunit rRNA gene surveys identified several hydrocarbon-degrading bacteria, supporting the possibility that microbes play a role in degrading PMD. Some Plastisphere members may be opportunistic pathogens (the authors, unpublished data) such as specific members of the genus Vibrio that dominated one of our plastic samples. Plastisphere communities are distinct from surrounding surface water, implying that plastic serves as a novel ecological habitat in the open ocean. Plastic has a longer half-life than most natural floating marine substrates, and a hydrophobic surface that promotes microbial colonization and biofilm formation, differing from autochthonous substrates in the upper layers of the ocean.