Spatial distribution of marine macro-litter on the seafloor in the northern Mediterranean Sea: the MEDITS initiative

Marine litter is one of the main sources of anthropogenic pollution in the marine ecosystem, with plastic representing a global threat. This paper aims to assess the spatial distribution of plastic macro-litter on the seafloor, identifying accumulation hotspots at a northern Mediterranean scale. Density indices (items km–2) from the MEDITS trawl surveys (years 2013-2015) were modelled by generalized additive models using a Delta-type approach and several covariates: latitude, longitude, depth, seafloor slope, surface oceanographic currents and distances from main ports. To set thresholds for the identification of accumulation areas, the percentiles (85th, 90th and 95th) of the plastic spatial density distribution were computed on the raster data. In the northern Mediterranean marine macro-litter was widespread (90.13% of the 1279 surveyed stations), with plastic by far the most recurrent category. The prediction map of the plastic density highlighted accumulation areas (85th, 90th and 95th percentiles of the distribution, respectively, corresponding to 147, 196 and 316 items km–2) in the Gulf of Lions, eastern Corsica, the eastern Adriatic Sea, the Argo-Saronic region and waters around southern Cyprus. Maximum densities were predicted in correspondence to the shallower depths and in proximity to populated areas (distance from the ports). Surface currents and local water circulation with cyclonic and anticyclonic eddies were identified as drivers likely facilitating the sinking to the bottoms of floating debris.


marine macro-litter, plastic, Mediterranean Sea, GAM modelling, accumulation areas, MEDITS

How to cite
Spedicato Maria Teresa, Zupa Walter, Carbonara Pierluigi, Fiorentino Fabio, Follesca Maria Cristina, Galgani Francois, Garcia-Ruiz Cristina, Jadaud Angelique, Ioakeimidis Christos, Lazarakis Giorgios, Lembo Giuseppe, Mandic Milica, Maiorano Porzia, Sartini Marina, Serena Fabrizio, Cau Alessandro, Esteban Antonio, Isajlovic Igor, Micallef Reno, Thasitis Ioannis (2019). Spatial distribution of marine macro-litter on the seafloor in the northern Mediterranean Sea: the MEDITS initiative. Scientia Marina. 83 (S1). 257-270.,

Copy this text