Integrating Lagrangian simulations of plastic pollution with chemical advection-diffusion processes to account for cetacean ingestion risk within the Pelagos Sanctuary

The Mediterranean Sea is heavily impacted by anthropogenic activities. Under the Marine Strategy Framework Directive, marine litter (Descriptor 10) has been recognized as one of the principal causes of marine pollution, and plastics is raising concern about impacts on marine wildlife. We investigated the risk of ingestion of plastic debris by marine biota by interlacing a decade (2000-2010) of microplastic concentration fields obtained through Lagrangian simulations with a Habitat Suitability Model (HSM) for our target species Balaenoptera physalus, an endangered cetacean for which there is increasing evidence of impacts due to microplastic ingestion. We released particles on a wide area embracing the Pelagos International Sanctuary for the Protection of Mediterranean Marine Mammals (North-Western Mediterranean, between France, Italy and Monaco), which harbors the summer feeding grounds of the fin whale. Maps of species exposure were obtained by feeding the HSM with chlorophyll-a satellite data and then overlapped with maps of plastic litter distribution derived from our oceanographic modelling, to obtain a spatially explicit indicator of the risk of plastic ingestion for the cetaceans feeding in the Sanctuary. Plastics also act as vectors of pollutants, in terms of both additives used for their production and other chemicals sorbed from the environment they float in. Therefore we propose a coupling of Lagrangian simulations with chemical advection-diffusion processes to start developing an integrated framework that allows a comprehensive analysis of the multi-faceted problems related to plastic contamination in the Mediterranean Sea.