Where are the global ocean priority conservation areas under the most severe threat from microplastics?

Microplastics (MPs) are a distinct threat to marine ecosystems and biodiversity, but there is a serious lack of assessment of risks posed by MPs to global hotspots of marine biodiversity. To assess the threat of marine MP contamination to global marine biodiversity, we identified priority conservation areas under high MP stress (density > 10(5 )km(2)) by integrating distribution data on global surface marine MPs with geographic data on three categories of hotspot areas for marine protection, namely Marine Protected Areas (MPAs), Ecologically or Biologically Significant Marine Areas (EBSAs), and seamounts. Then, their social and natural influences were analyzed. A total of 1814 MPAs (5.8 million km(2)), 58 EBSAs, and 5125 seamounts under high MP stress were identified. In the sea areas under national jurisdiction, the proportion of MPAs under high MP stress showed a quadratic relationship with the country's GDP per capita, reaching a maximum at a GDP per capita of around $45,000, and a positive correlation with the population size and density of the country where they are located. On the high seas, a total of 12 EBSAs and 49 shallow and mid-depth seamounts under high MP stress were identified, which implied that these areas should be recognized as a priority for conservation in the Biodiversity Beyond National Jurisdiction (BBNJ) framework. This study provides an actionable reference for the subsequent incorporation of MP stress into a global, BBNJ-framework pathway for high seas protection.