Like a chunky soup. In the subtropical gyre of the North Pacific Ocean, home to the North Pacific Garbage Patch – better known as the "plastic continent" – the concentration of small-sized plastic debris has soared, according to a study by the NGO The Ocean Cleanup published on Tuesday, November 19, in the journal Environmental Research Letters. In this area, which spans six times the size of France, up to 10 million microparticles per square kilometer could be found in 2022 – 10 times more than in 2015.
"These data were collected thanks to our cleanup operations at sea," said Laurent Lebreton, head of research at the NGO and first author of the study. "Cleanup operations are not only essential for reducing the vast accumulation of plastics in the ocean, but they also provide us with a unique platform to gather valuable date in remote regions," he pointed out. In his view, the clear accumulation of small plastic fragments in the vortex, in the space of just seven years, is "deeply concerning," because "even though we knew that pollution was getting worse, we didn't expect such an increase."
"We suspected that there was an accumulation of microplastics in the ocean, but this had not yet been proved," said Jean-François Ghiglione, research director at the French National Centre for Scientific Research's Microbial Oceanography Laboratory, who was not involved in the study. "In most studies, samples are taken in a somewhat random fashion, but here, [the researchers] went to the same place for seven years, in the North Pacific gyre – the only ones to go so regularly – and gradually observed the changes over time."
The work is based on the analysis of data collected during 50 expeditions between 2015 and 2022, involving more than a thousand samples – collected using nets of various sizes – and several dozen aerial observations using planes and drones.
The results show that within the trash vortex, the mass concentration of plastic fragments smaller than 5 centimeters (which includes microplastics from 0.5 to 5 millimeters and mesoplastics from 5 millimeters to 5 centimeters) has risen from an average of 2.9 kilograms per square kilometer in 2015, to 14.2 kilograms per square kilometer in 2022. Their number has also increased significantly. According to Ghiglione, this plastic continent to the east of Hawaii "absorbs everything around it due to meteorological phenomena that cause the current to settle."
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