Investigating the Dispersion Processes Contributing to the Displacement of Marine Plastic Litter Through Coastal Systems Using Drifter Release Experiments and Lagrangian Tools

This study explores the dispersion processes driving the movement of marine plastic litter through coastal systems: it is based on an integrated approach of field experiments, numerical modeling and citizen science. To pursue the objectives of the study, a numerical modeling system based on SHYFEM (the hydrodynamic componen<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sup> of the system) and OpenDrift (the Lagrangian component) models was implemented in the northeastern Ligurian Sea. The hydrodynamic component was validated against temperature and sea level in situ data, as well as through current velocity measurements obtained via high-frequency radar: it has proved to be robust and accurate in reproducing small-scale coastal features such as localized turbulence and the plumes of both the Arno and the Magra rivers. OpenDrift was validated and calibrated using tracks recorded from low-cost drifters, assembled involving high school students, released in several dispersion experiments. The simulated Lagrangian trajectories were used to investigate the different forces acting on marine plastic litter, thereby predicting various dynamic scenarios in the studied coastal area.