Plastic marine debris or the plastisphere impacts marine organisms through ingestion, entanglement, and as a source of toxic chemicals. The plastisphere could also have a major impact on biogeochemical cycles in the oceans. Plastics are transported via major ocean currents to central gyres, where they reside for decadal time scales. The amount of plastic waste is large, exceeding 2 kg/ km2 in central gyres. Even the most recent ocean surveys cannot account for the amount of debris estimated to enter the ocean, with inputs and outputs differing by orders of magnitude. Although studies conducted in the laboratory indicate that the most common plastics (polyethylene, polypropylene, polyvinyl chloride, polystyrene, and others) can be degraded by microorganisms, it is unclear whether microbes of the plastisphere can directly degrade plastic resins.
The objective of this project will be to elucidate the rates, metabolic pathways, and controls of microbial plastic degradation in oceanic environments. Over the long term, the project seeks to provide the fundamental science to support the manufacture of plastics that will more readily biodegrade in the oceans. The project will closely couple environmental genomics and with biogeochemistry in the Konstantinidis and Kostka labs, respectively, to address this important problem in the oceans.