In the study the researchers highlight the pervasiveness of plastic pollution in the Mediterranean seabasin and possible issues with biodegradable plastics. During their research campaign the scientists found polycaprolactone (PCL), a petroleum-based polyester commonly used for 3D printing in 9.5% of their net tows. The particular plastic is considered biodegradable in terrestrial environment with a degradation time of 6–12 days in laboratory conditions. Their findings indicate though that these plastics do not readily degrade in natural sea conditions thus not representing an a priori solution for reducing marine litter.
The study further suggests that the sinks, sources, fate and residence times of different polymers are among the main knowledge gaps to be addressed, especially with regard to the smaller size classes. In addition, the scientists urgently call for data from the eastern Mediterranean Sea as numerical simulations predict preferential accumulation in the levantine basin. Its is concluded as well that polymeric characterization of plastic particles is of paramount importance for a proper assessment of plastic contamination in the marine environment and for the effective identification of specific solutions and alternatives.
The Mediterranean Sea is the largest and deepest enclosed sea on earth, hot-spot of marine biodiversity and cradle of human civilization, whose unique outflow of water occurs at depth from the narrow Strait of Gibraltar. Being one of the busiest navigation crossroads and top touristic destinations in the world, surrounded by a heavily populated and industrialized coastline, it is not surprising that in this basin, the impacts of human activities are proportionally stronger than in any other sea.
The research was supported by the JPI Oceans BASEMAN
project, one of four projects
looking into the ecological aspects of microplastics in the marine environment.
Suaria, G. et al. The Mediterranean Plastic Soup: synthetic polymers in Mediterranean surface waters. Sci. Rep. 6, 37551; doi: 10.1038/srep37551 (2016).