Modeling of small sea floaters in the central Mediterranean Sea: seasonality of at-sea distributions

Abstract

Floating marine debris represent a threat to marine and coastal ecology. Since the Mediterranean basin is one of the highly impacted regions, both by the coastal pollution as well as from sea traffic, the potential harm of a floating pollution on the marine ecology could be overwhelming in this area. Our study area covers the central Mediterranean crossing that connects the western and eastern Mediterranean and is one of the areas impacted by a high intensity of sea traffic. To identify regions in the central Mediterranean that could be more exposed by high concentration of floating marine pollutants we use Leeway model for lower windage small-size particles. We perform numerical simulation of a large ensemble of Lagrangian particles that approximate at-sea debris. The particles are forced by high-resolution sea kinematics from the Copernicus Marine Environment Monitoring Service (CMEMS) and 10 m atmospheric wind from the European Centre for Medium-Range Weather Forecasts (ECMWF) for two reference periods in summer and winter of 2013--2016. We identify the regions with a high accumulation of particles in terms of particle surface densities per unit area. Although seasonal and annual variability of ocean current and atmospheric wind is an important factor that influences accumulation regimes across the central Mediterranean, we found that the border of the Libyan shelf harbors larger percentage of particles after 30 days of simulation.