Peipei Wu, Ruochong Xu, Xuantong Wang, Amina T Schartup, Arjen Luijendijk, Yanxu Zhang

Mismanaged plastics accumulate in oceans and threaten marine life. About 40 million tonnes of plastics have reached the oceans, where their fate remains unclear. To track the sources, sinks, sizes, and age of all-time released plastics, we developed a new mechanistic model and synthesized decades of measurements. We find that Asian plastics are the largest contributor (76%) to marine plastics by mass but only affect the North Pacific and the Indian Ocean, whereas plastics from fishing and shipping activities contribute 24% by mass but cover 60% of the ocean surface. Using the model, we demonstrate that biologically productive nearshore (63%) or upper ocean (25%) ecosystems trap 88% of the marine plastic. This study provides a model framework to assess the potential effect of future mitigation strategies.