The physical oceanography of the transport of floating marine debris

TLDR

Marine plastic debris floating on the ocean surface is a major environmental problem, yet its distribution is poorly mapped and most of the waste entering from land remains unaccounted for. Understanding how plastic debris is transported from coastal and marine sources is essential to close the global inventory and inform mitigation, while also using plastic as a tracer to learn about ocean physics across scales. The review synthesizes literature on transport processes in open ocean and coastal zones, drawing on measurements, remote sensing, and numerical simulations to elucidate interactions across spatio‑temporal scales.

Abstract

Abstract Marine plastic debris floating on the ocean surface is a major environmental problem. However, its distribution in the ocean is poorly mapped, and most of the plastic waste estimated to have entered the ocean from land is unaccounted for. Better understanding of how plastic debris is transported from coastal and marine sources is crucial to quantify and close the global inventory of marine plastics, which in turn represents critical information for mitigation or policy strategies. At the same time, plastic is a unique tracer that provides an opportunity to learn more about the physics and dynamics of our ocean across multiple scales, from the Ekman convergence in basin-scale gyres to individual waves in the surfzone. In this review, we comprehensively discuss what is known about the different processes that govern the transport of floating marine plastic debris in both the open ocean and the coastal zones, based on the published literature and referring to insights from neighbouring fields such as oil spill dispersion, marine safety recovery, plankton connectivity, and others. We discuss how measurements of marine plastics (both in situ and in the laboratory), remote sensing, and numerical simulations can elucidate these processes and their interactions across spatio-temporal scales.