Beaches of the Azores archipelago as transitory repositories for small plastic fragments floating in the North-East Atlantic

Catégorie : Modélisation de Pollution Plastique Marine
Date :29 juin 2020
Avis TSC : La pollution plastique ne connaît pas de frontière. Cet exemple montre bien comment un archipel d’îles, aux Açores, se retrouve impacté par une pollution qui ne provient pas de son activité nationale. Et il ne s’agit pas d’un phénomène ponctuel, car un suivi sur 33 mois et sur 7 plages a montré que les types de plastiques étaient identiques et provenaient très probablement de la même source.
Pham, Christopher K.; Pereira, João M.; Frias, João P. G. L.; Ríos, Noelia; Carriço, Rita; Juliano, Manuela; Rodríguez, Yasmina.
Environmental pollution (Barking, Essex: 1987) : 263 (DocId: Pt A) 114494 (2020).
Plastic pollution is among the most pervasive stressors currently influencing the marine environment and affecting even the most remote areas. To date, there are still fundamental gaps in our understanding of the major pathways and fate of plastic debris in the oceans. Here we show that oceanic insular environments are important transitory repositories of small plastic items floating in the open ocean. Monthly monitoring of seven beaches over a three-year period demonstrate that beaches of the Azores islands with particular characteristics can capture significant quantities of fragments between 2 and 5 mm in length. The beach with the highest plastic loading rates was found to occasionally accumulate densities exceeding 15,000 fragments m-2 on part of the backshore. However, a large portion of these fragments can be rapidly washed back into the marine environment. Detailed characterization of those plastic items revealed the typology and size distribution to be similar throughout the seven beaches and through the 33 months surveyed, suggesting a same and unique source. Our results show that these oceanic islands of the North-East Atlantic are under pressure of high quantities of fragmented plastic debris that probably entered the ocean many years ago.