Numerical investigation of the three-dimensional paths of plastic polymers in the Gulf of Naples.

The high-resolution Campania Regional Ocean Model (CROM), coupled with an online Lagrangian particle tracking algorithm, is used to investigate the horizontal and vertical behavior of different (in terms of size and density) plastic polymer types during February and August 2016 in the Gulf of Naples. The transport of passive particles is evaluated based on the three-dimensional Eulerian velocity fields provided by the ocean model. The virtual particles are released in several hot spot areas in the Gulf of Naples where most of the marine debris is supposed to come from. A sensitivity analysis on the vertical sinking for negatively buoyant particles is carried out. The sinking behavior is determined by the settling velocity, which depends on the physical properties of the individual litter item as well as on the hydrodynamical features of the marine environment. Different numerical experiments are carried out to evaluate the effect of marine dynamics on three-dimensional transport. • 3D Lagrangian tracking plastic in the Gulf of Naples using the high-resolution Campania Regional Ocean Model • Sensitivity analysis on the vertical sinking for different plastic polymer types • Assessment of residence times and potential accumulation zones of the involved pollutants • Influence of seasonal hydrodynamical features of the water column on particle dynamics [ABSTRACT FROM AUTHOR]