Influence of waves on the three-dimensional distribution of plastic in the ocean. (February 2023)

• Record Type: Journal Article
• Authors: Bajon, Raphaël; Huck, Thierry; Grima, Nicolas; Maes, Christophe; Blanke, Bruno; Richon, Camille; Couvelard, Xavier
• Is Part Of: Marine pollution bulletin. Volume 187(2023)
• Publication Date: 2023-02
• Subjects: Microplastics -- Marine debris -- Plastic discharge -- Ocean-wave coupling -- Stokes drift -- Three-dimensional circulation; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2022.114533
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: The world's oceans are facing plastic pollution, 80 % of which of terrestrial origin flowing from the mismanaged waste of coastal populations and from river discharge. To study the fate of this pollution, the three-dimensional trajectories of neutral plastic particles continuously released for 24 years according to realistic source scenarios are computed using currents from a global ocean-wave coupled model at 1 4 ∘ resolution and from a reference ocean-only model. These Lagrangian simulations show that neutral particles accumulate at the surface in the subtropical convergence zones from where they penetrate to about 250 m depth and strongly disperse over 40 ∘ of latitude. About 5.3 % of the particles remain at the surface with the wave-coupled model currents, whereas only 2 % for the uncoupled model, with some modulation in the location of the convergence zones. Increased surface retention results from upward vertical velocities induced by widespread divergence of waves-induced Stokes transport in the surface layers. Highlights: Land-based scenario considers plastic waste from coastal populations or brought by rivers. 3D global dispersion of neutral 'plastic' particles in the global ocean Coupled ocean-wave dynamics increase the surface retention of plastic by a factor of Shapes of the concentrated plastic areas change when coupling with waves. Ocean-wave coupling induces upward velocities below subtropical convergence zones.