A new study involving researchers from the CNRS, the Nelson Mandela University and the Strathclyde University (Scotland) provided evidence of possible microplastic transportation from the ocean to the surrounding atmosphere, by the waves and the wind. This marks a significant step for research and a strong stance for reducing plastic consumption.
The scientists estimate that around 10% of the plastic we produce end up in the ocean. We usually acknowledge that once plastics enter the ocean, washed down from coastal areas, they are there to stay. What if the ocean was not only a plastics sink, but had also become a source?
“The presence of microplastics in remote locations such as the Artic snow and the lake beaches on the Tibetan plateau suggest that they must have been transported there by the wind.” Said Kerry Moss, oceanography student at Nelson Mandela University. “We thus wondered where these atmospheric microplastics could come from. The oceans are part of the answer.”
The scientists showed that microplastic particles could be ejected from the ocean to the atmosphere, along with sea salt, bacteria, viruses and algae. This occurs where waves break, as they trap bubbles of air into the ocean. The bubbles collect micro and nano-particles in the water, before rising to the surface and bursting. Some of the particles collected being microplastics, they are released in the atmosphere and available for wind transport.
The scientific team tested this hypothesis in the field, on the Atlantic Coast of France. They set up two air samplers on a dune near the ocean for several days. Sea spray was filtered to collect the particles it carried. Gaël Le Roux, CNRS research at the Functional ecology and environment Laboratory confirms the results: “We found microplastics in all samples throughout the study. This provides early evidence of microplastics exchange from the ocean to the atmosphere and of their transport by sea spray.” Given the quantity of microplastics collected, the scientists extrapolated and estimated that 136,000 tons of microplastics could be blown onshore every year on the planet.
Reference : Allen S, Allen D, Moss K, Le Roux G, Phoenix VR, Sonke JE (2020), Examination of the ocean as a source for atmospheric microplastics. PLoS ONE 15(5): e0232746.