Scientific Publications

The distribution of subsurface microplastics in the ocean

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April 2025, article in a peer reviewed Journal
Nature

Shiye Zhao, Karin F. Kvale, Lixin Zhu, Erik R. Zettler, Matthias Egger, Tracy J. Mincer, Linda A. Amaral-Zettler, Laurent Lebreton, Helge Niemann, Ryota Nakajima, Martin Thiel, Ryan P. Bos and Luisa Galgani & Aron Stubbins

  • Journal: Nature
  • Publication type: article in a peer-reviewed Journal
  • Collaborators: Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan. Aotearoa Blue Ocean Research, Lower Hutt, New Zealand. State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China. Department of Marine and Environmental Sciences, Northeastern University, Boston, MA, USA. NIOZ Royal Netherlands Institute for Sea Research, Den Burg, The Netherlands. The Ocean Cleanup, Rotterdam, The Netherlands. Empaqtify, St Gallen, Switzerland. Harriet Wilkes Honors College, Florida Atlantic University, Boca Raton, FL, USA. Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands. Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands. Facultad Ciencias del Mar, Universidad Catolica del Norte, Coquimbo, Chile. MarineGEO Program, Smithsonian Environmental Research Center, Edgewater, MD, USA. Centre for Ecology and Sustainable Management of Oceanic Island (ESMOI), Coquimbo, Chile. Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA. Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy. National Biodiversity Future Center (NBFC), Palermo, Italy. Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA. Department of Civil and Environmental Engineering, Northeastern University, Boston, MA, USA.
  • Publication date: April 30, 2025
  • DOI: 10.1038/s41586-025-08818-1

Abstract

Marine plastic pollution is a global issue, with microplastics (1 µm–5 mm) dominating the measured plastic count. Although microplastics can be found throughout the oceanic water column, most studies collect microplastics from surface waters (less than about 50-cm depth) using net tows. Consequently, our understanding of the microplastics distribution across ocean depths is more limited. Here we synthesize depth-profile data from 1,885 stations collected between 2014 and 2024 to provide insights into the distribution and potential transport mechanisms of subsurface (below about 50-cm depth, which is not usually sampled by traditional practices) microplastics throughout the oceanic water column. We find that the abundances of microplastics range from 1e−4 to 1e4 particles per cubic metre. Microplastic size affects their distribution; the abundance of small microplastics (1 µm to 100 µm) decreases gradually with depth, indicating a more even distribution and longer lifespan in the water column compared with larger microplastics (100 µm to 5,000 µm) that tend to concentrate at the stratified layers. Mid-gyre accumulation zones extend into the subsurface ocean but are concentrated in the top 100 m and predominantly consist of larger microplastics. Our analysis suggests that microplastics constitute a measurable fraction of the total particulate organic carbon, increasing from 0.1% at 30 m to 5% at 2,000 m. Although our study establishes a global benchmark, our findings underscore that the lack of standardization creates substantial uncertainties, making it challenging to advance our comprehension of the distribution of microplastics and its impact on the oceanic environment