Early microbial biofilm formation on marine plastic debris.

An important aspect of the global problem of plastic debris pollution is plastic buoyancy. There is some evidence that buoyancy is influenced by attached biofilms but as yet this is poorly understood. We submerged polyethylene plastic in seawater and sampled weekly for 3 weeks in order to study early stage processes. Microbial biofilms developed rapidly on the plastic and coincided with significant changes in the physicochemical properties of the plastic. Submerged plastic became less hydrophobic and more neutrally buoyant during the experiment. Bacteria readily colonised the plastic but there was no indication that plastic-degrading microorganisms were present. This study contributes to improved understanding of the fate of plastic debris in the marine environment.