Author(s): Agnese Pini; Paolo Bello; Paolo Monti; Giovanni Leuzzi
Linked Author(s): Giovanni Leuzzi
Keywords: Microplastic; 3D dispersion; Vertical turbulent diffusivity; Stochastic model
Abstract: Microplastic (MP) marine contamination is an issue widely addressed in literature due to the implications for humans and the environment. MPs has in fact been detected throughout the compartment, in surface, intermediate and deep waters, seabeds and beaches and in marine organisms. In the recent years the problem has been investigated in both sampling campaign and numerical dispersion models. The former are fundamental to obtain information on the level of contamination of the investigated area and detect the final effect of the MP dispersion. Numerical models, considering the various factors that contribute to MP transport and diffusion, allow both to investigate the individual influence of these and to evaluate their overlap. Furthermore, if applied over sufficiently large time intervals and spatial domains, they allow highlighting the contribution of seasonal phenomena as well as the role of sources. While, to date, there is numerous data related to campaigns carried out on the surface, those related to the underlying layers are rarer. The models therefore become a fundamental tool to investigate the dispersion of MPs over the water column. In this work, the role of the main forcings, mean current transport, turbulence and characteristics of the particles that determine their vertical velocity, which intervene in determining the diffusion on the surface and along the water column, is numerically investigated by means of a 3D Lagrangian dispersion model developed by the authors. Long term simulations are conducted to infer concentration maps and vertical profiles. The latter are compared with the available experimental data.
Year: 2024