Plastic could pollute the ocean surface for over a century

Researchers from Queen Mary University of London have predicted the phenomena's 100 year potential.

It was found that the plastic persistence remains even if all plastic inputs into the ocean are stopped immediately.

The study was completed in collaboration with HR Wallingford Ltd and combines expertise in marine geochemistry, fluid dynamics and environmental modelling.

Using a model that simulates the slow breakdown of large plastic particles and their interaction with marine snow (sticky organic material that helps transport debris to the deep sea), the researchers show that the degradation process is the limiting factor in removing plastic from the surface.

The findings help explain the persistent mismatch between the amount of buoyant plastic entering the ocean and the relatively small amounts observed at the surface – often referred to as the ‘missing plastic’ problem.

Dr Nan Wu, the paper’s lead author from Queen Mary University of London, says, ‘People often assume that plastic in the ocean just sinks or disappears. But our model shows that most large, buoyant plastics degrade slowly at the surface, fragmenting into smaller particles over decades…Even after 100 years, about 10% of the original plastic can still be found at the surface.’

The research appears in Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. It is the third and final paper in a trilogy that explores the long-term fate of microplastics in the ocean.

It builds on earlier research featured in Nature Water and Limnology & Oceanography, which offers a picture of how plastic pollution moves from ocean surface to seafloor.