In search for the sources of plastic marine litter that contaminates the Easter Island Ecoregion

Abstract

Subtropical gyres are the oceanic regions where plastic litter accumulates over long timescales, exposing surrounding oceanic islands to plastic contamination, with potentially severe consequences on marine life. Islands’ exposure to such contaminants, littered over long distances in marine or terrestrial habitats, is due to the ocean currents that can transport plastic over long ranges. Here, this issue is addressed for the Easter Island ecoregion (EIE). High-resolution ocean circulation models are used with a Lagrangian particle-tracking tool to identify the connectivity patterns of the EIE with industrial fishing areas and coastline regions of the Pacific basin. Connectivity patterns for “virtual” particles either floating (such as buoyant macroplastics) or neutrally-buoyant (smaller microplastics) are investigated. We find that the South American shoreline between 20°S and 40°S, and the fishing zone within international waters off Peru (20°S, 80°W) are associated with the highest probability for debris to reach the EIE, with transit times under 2 years. These regions coincide with the most-densely populated coastal region of Chile and the most-intensely fished region in the South Pacific. The findings offer potential for mitigating plastic contamination reaching the EIE through better upstream waste management. Results also highlight the need for international action plans on this important issue.

Sea-Surface Slicks and Their Effect on the Concentration of Plastics and Zooplankton in the Coastal Waters of Rapa Nui (Easter Island)

“…Many types of plastics are positively buoyant, and as passive particles they are transported by currents and concentrated in the large oceanic gyres (Maximenko et al, 2012;van Sebille et al, 2020). Dense accumulations of floating plastics, mainly from the mainland and industrial fisheries, are also found in the center of the South Pacific Subtropical Gyre (SPSG), which is close to Rapa Nui (Easter Island) (Eriksen et al, 2013(Eriksen et al, , 2018Miranda-Urbina et al, 2015;van Gennip et al, 2019).…”

A country's response to tackling plastic pollution in aquatic ecosystems: The Chilean way

“…In central and southern Chile, large amounts of plastics are also reaching the coastal waters through rivers(Rech et al, 2014;Rech et al, 2015). On oceanic islands and in oceanic waters, most recognizable marine litter items are plastics that come from the open ocean fisheries and the continental coast of South America(Kiessling et al, 2017;Luna-Jorquera et al, 2019;Miranda-Urbina, Thiel, & Luna-Jorquera, 2015), which is confirmed by a recent study using modelling techniques(van Gennip et al, 2019). The need for protecting oceanic islands through declaring them marine protected areas has been broadly accepted as a conservation tool for preserving the unique biodiversity they harbour.…”

“…Petit, Campoy, Hevia, Gaymer, & Squeo, 2018). Plastic pollution, however, has reached the remote Chilean oceanic islands (Easter Island and Juan Fernandez), which receive huge volumes of marine litter coming from the continental coast of Chile and the industrial fishery (Luna-Jorquera et al, 2019;van Gennip et al, 2019). This opened a debate on whether these conservation instruments are sufficient to prevent plastics from entering protected areas (Barnes et al, 2018;Luna-Jorquera et al, 2019).…”

A Blueprint for an Inclusive, Global Deep-Sea Ocean Decade Field Program

“…Nevertheless, we lack information on how these materials spread, whether a gradient of contamination decreases away from terrestrial sources, or how, and for how long, they move into the deep sea. High resolution ocean circulation models (van Gennip et al, 2019), indicate a ∼2 year transit time of the litter produced in the western coast of South America, including debris produced by the industrial fishery operating in the high seas off Chile and Peru, to the center of the South Pacific Gyre. However, we lack any reliable estimate of the portion of this debris reaching the deep sea and the time it takes.…”