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

Modeling the Exposure of the Macaronesia Islands (NE Atlantic) to Marine Plastic Pollution

“…In fact, the exposure of the Azores islands to the confluence of filaments and eddies pitching off from the Gulf Stream and from the Azores Current led Sala et al (2016) to propose the archipelago as a potential retention zone for floating particles. Such hypothesis was later reinforced by Pham et al (2020), who found that the Azorean beaches retain significant quantities of small fragments that are rapidly washed back to sea, acting as transitory repositories of small fragments in the region. After intersecting the Azorean area, drifters are mostly advected southward and eastward with varying meridional deflections, 3B, 1A).…”

“…Low windage coefficients are used in particles with low buoyancy and limited surface area exposed to the wind, whereas high windage coefficients are used for highly buoyant particles with large exposed surface area (Chubarenko et al, 2016). Considering the variety of marine plastic litter densities and shapes found in the Macaronesia region (e.g., Ríos et al, 2018;Fernandes, 2019;Herrera et al, 2020;Pham et al, 2020), our model particles were divided into five groups with random windage coefficients ranging from 0 to 1%, 1 to 2%, 2 to 3%, 3 to 4%, and 4 to 5% of the wind at 10 m height. This means that all grid cells arranged around the islands contributed with the release of five particles every 3 days, except when particles were initiated on land (Figure 2).…”

“…For this reason, common patterns in the transport of incoming marine litter are expected to occur between the archipelagos. However, although recent studies strongly suggest that most of the debris collected on the Macaronesian islands come from the open ocean (e.g., Baztan et al, 2014;Fernandes, 2019;Álvarez et al, 2020;Pham et al, 2020), the exposure of the archipelagos to the regional transport of marine litter has, to the best of our knowledge, not been addressed to present date.…”

“…The growing accumulation of plastic litter in the marine environment poses an unattended environmental threat to islands, as they become increasingly exposed to pollution of which they have very little control (e.g., Baztan et al, 2014;Monteiro et al, 2018;Pham et al, 2020;Pieper et al, 2020). Its impacts are extensive and can be felt on highly vulnerable socio-economic sectors of which islands depend on, such as tourism, fisheries and shipping industries (Rodríguez et al, 2020).…”

Deep learning approach for automatic microplastics counting and classification

“…In this sense, some indirect techniques have been developed to have an estimation of the amount of plastics in the ocean. One of them is based on the monitoring the plastics on the beach as they act as sentinel (Pham et al, 2020). Besides the marine J o u r n a l P r e -p r o o f…”