How much plastic gets trapped and filtered?
Plastics have shown up everywhere on the planet, even showing up in human blood, so it isn’t surprising that they can be found on the bottom of the ocean.
Posidonia oceanica is a moderate species that often roll ashore onto beaches during the autumn–often driven to land during storms and periods of strong waves–but its leaf sheaths situated near the underground roots will get buried by sediments. It is during that ordeal that the fibres that are let go will eventually create what are called “ball-shaped agglomerates known as seaballs,” or “Neptune balls,” researchers said.
As a result, they can, and do, engulf surrounding items, including small pieces of plastic.
Posidonia oceanica spheroid on the beach. (Ezu (Martino A. Sabia)/Flickr. CC BY 2.0)
Scientists with the University of Barcelona found that plastic debris was contained in half of the loose seagrass leaf samples they collected–with 61.29 per cent of the plastic objects being small fragments. As much as 1,470 plastic items per kilogram of plant material was uncovered. The plastics were mostly made of negatively buoyant polymer filaments and fibres.
“We cannot completely know the magnitude of this plastic export to the land. However, first estimations reveal that Posidonia balls could catch up to 867 million plastics per year,” said Anna Sànchez-Vidal, a researcher at the University of Barcelona and co-author of the study, in a news release.