Research group IGV's Geochemistry group

A recent study in Nature Geoscience offers important new insights into the hidden role of ancient groundwater beneath the ocean floor – and how it may have interacted with ice sheets and rising sea levels during past climate changes.

27 million tons. That is the total estimated amount of plastic floating in the North Atlantic Ocean as particles of less than one micrometer each. This is shown by a comprehensive study recently published in the scientific journal Nature. “Measuring nanoplastics in environmental samples is extremely challenging. That’s why this novel pollutant has remained hidden for so long in our methodological blind spot. Our results were surprising - there is a similar or even greater amount of nanoplastics in this part of the ocean compared to microplastics. It’s quite widespread, and we detected it at depths greater than 4,500 meters," Dušan Materić says. He is head of the nanoplastics research group at the Helmholtz Centre for Environmental Research (UFZ) in Germany, and one of this year’s nominees from SU for the Swedish Wallenberg Academy Fellows program.   Ocean expedition Sophie ten Hietbrink is a PhD student at the Department of Geological Sciences at Stockholm University. During her master´s degree at Utrecht University, she spent four weeks aboard the research vessel RV Pelagia . On a trip from the Azores to the continental shelf of Europe, she took water samples at twelve locations. Anything larger than one micrometer was filtered out.  “By drying and heating the remaining material, we were able to measure the characteristic molecules of different types of plastics, using mass spectrometry,” says Sophie ten Hietbrink.   Shocking amount Extrapolating the results from different locations to the whole of the North Atlantic Ocean, the researchers arrived at the immense amount of 27 million tons of nanoplastics.  “A shocking amount. But with this we do have an important answer to the paradox of the missing plastic,” says Sophie ten Hietbrink.  Until now, not all the plastic that was ever produced in the world could be recovered. So, it turns out that a large portion is now floating in the water as tiny particles. The research provides the first estimate of the amount of nanoplastics in the oceans.   Sun, rivers and rain The nanoplastics can reach water by various routes. Larger particles can disintegrate under the influence of sunlight. Some nanoplastics probably flows along with river water. It also appears that nanoplastics reach the oceans through the air, as suspended particles fall down with rainwater or fall from the air onto the water surface as ‘dry deposition’.  “Now that we know they are so ubiquitous in the oceans, it's also obvious that they penetrate the entire ecosystem; from microorganisms to fish and humans,” says Helge Niemann. He is a researcher at the Royal Netherlands Institute for Sea Research (NIOZ) and professor of geochemistry at Utrecht University.     Is there a solution? Nanoplastics are a serious environmental problem, and they are here to stay. But according to Dušan Materić, two key strategies come to mind: prevention and mitigation. “Prevention means reducing unnecessary production, like in fast fashion, and replacing plastics with natural materials or effective alternatives. And no, ‘degradable’ or ‘compostable’ plastics are often not good substitutes, they are usually just weaker plastics that break down faster into nanoplastics.” As for mitigation, most methods are still under development and tend to be expensive solutions for a global problem.  “However, some of these technologies can be effectively applied in pollution hot spots, where they make the most impact,” says Dušan Materić.   Full article Nanoplastic concentrations across the North Atlantic is published in the journal Nature DOI: 10.1038/s41586-025-09218-1 More reading More about Sophie ten Hietbrink and contact details Helmholtz Centre for Environmental Research (UFZ) Utrecht University Royal Netherlands Institute for Sea Research