Plastic Pollution in the World's Oceans: More than 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea

Trillion Plastic Pieces Weighing over Plastic Pollution in the World's Oceans: More than 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea Marcus Eriksen * 0 1 2 3 12 Laurent C. M. Lebreton 0 1 2 4 13 Henry S. Carson 0 1 2 5 6 Martin Thiel 0 1 2 7 8 9 Charles J. Moore 0 1 2 10 Jose C. Borerro 0 1 2 11 Francois Galgani 0 1 2 Peter G. Ryan 0 1 2 Julia Reisser 0 1 2 0 Competing Interests: Jose Borerro is affiliated wih eCoast Ltd., and this affiliation does not alter the authors' adherence to PLOS ONE policies on sharing data and materials. Laurent C. M. Lebreton is affiliated with Dumpark Creative Industries Ltd., and this affiliation does not alter the authors' adherence to PLOS ONE policies on sharing data and materials 1 Funding: Financial support from the Will J. Reid Foundation (HSC) and Seaver Institute (ME) made much of this work possible. J. Reisser is sponsored by an IPRS and a CSIRO9s Flagship Postgraduate scholarship and M. Thiel was supported by the Chilean Millennium Initiative (grant NC120030). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript 2 Editor: Hans G. Dam, University of Connecticut , United States of America 3 Five Gyres Institute , Los Angeles, California , United States of America, 4 Dumpark Data Science , Wellington , New Zealand, 5 Marine Science Department, University of Hawaii at Hilo , Hilo, Hawaii , United States of America, 6 Washington Department of Fish and Wildlife , Olympia, Washington , United States of America, 7 Facultad Ciencias del Mar, Universidad Cat o lica del Norte , Coquimbo , Chile, 8 Millennium Nucleus Ecology and Sustainable Management of Oceanic Island (ESMOI) , Coquimbo , Chile, 9 Centro de Estudios Avanzados en Zonas A ridas (CEAZA) , Coquimbo , Chile, 10 Algalita Marine Research and Education , Long Beach, California , United States of America, 11 eCoast Limited , Raglan , New Zealand , 10. Departement Oce anographie et Dynamique des Ecosystemes, Institut franc ais de recherche pour l9exploitation de la mer (Ifremer) , Bastia, Corsica, France, 1 12 Percy FitzPatrick Institute of African Ornithology, University of Cape Town , Rondebosch, South Africa, 1 13 School of Environmental Systems Engineering and Oceans Institute, University of Western Australia , Crawley, Perth , Australia Plastic pollution is ubiquitous throughout the marine environment, yet estimates of the global abundance and weight of floating plastics have lacked data, particularly from the Southern Hemisphere and remote regions. Here we report an estimate of the total number of plastic particles and their weight floating in the world's oceans from 24 expeditions (2007-2013) across all five sub-tropical gyres, costal Australia, Bay of Bengal and the Mediterranean Sea conducting surface net tows (N5680) and visual survey transects of large plastic debris (N5891). Using an oceanographic model of floating debris dispersal calibrated by our data, and correcting for wind-driven vertical mixing, we estimate a minimum of 5.25 trillion particles weighing 268,940 tons. When comparing between four size classes, two microplastic ,4.75 mm and meso- and macroplastic .4.75 mm, a tremendous loss of microplastics is observed from the sea surface compared to expected rates of fragmentation, suggesting there are mechanisms at play that remove ,4.75 mm plastic particles from the ocean surface. - Plastic pollution is globally distributed across all oceans due to its properties of buoyancy and durability, and the sorption of toxicants to plastic while traveling through the environment [1, 2], have led some researchers to claim that synthetic polymers in the ocean should be regarded as hazardous waste [3]. Through photodegradation and other weathering processes, plastics fragment and disperse in the ocean [4, 5], converging in the subtropical gyres [69]. Generation and accumulation of plastic pollution also occurs in closed bays, gulfs and seas surrounded by densely populated coastlines and watersheds [1013]. The impact of plastic pollution through ingestion and entanglement of marine fauna, ranging from zooplankton to cetaceans, seabirds and marine reptiles, are well documented [14]. Adsorption of persistent organic pollutants onto plastic and their transfer into the tissues and organs through ingestion [15] is impacting marine megafauna [16] as well as lower trophic-level organisms [17, 18] and their predators [19, 20]. These impacts are further exacerbated by the persistence of floating plastics, ranging from resin pellets to large derelict nets, docks and boats that float across oceans and transport microbial communities [21], algae, invertebrates, and fish [22] to non-native regions [23], providing further rationale to monitor (and take steps to mitigate) the global distribution and abundance of plastic pollution. Despite oceanographic model predictions of where debris might converge [24] estimates of regional and global abundance and weight of floating plastics have been limited to microplastics ,5 mm [19, 25]. Using extensive published and new data, particularly from the Southern Hemisphere subtropical gyres and marine areas adjacent to populated regions [7, 10, 13, 26], corrected for wind-driven vertical mixing [27], we populated an oceanographic model of debris distribution [28] to estimate global distribution and count and weight densities of plastic pollution in all sampled size classes. The oceanographic model assumes that amounts of plastic entering the ocean depend on three principal variables: watershed outfalls, population density and maritime activity. The dataset used in this model is based on expeditions from 20072013 (Table S1), surveying all five sub-tropical gyres (North Pacific, North Atlantic, South Pacific, South Atlantic, Indian Ocean) and extensive coastal regions and enclosed seas (Bay of Bengal, Australian coasts and the Mediterranean Sea), and include surface net tows (N5680) and visual survey transects for large plastic debris (N5891) totaling 1571 locations in all oceans (Fig 1). We also compared plastic pollution levels between oceans and across four size classes: 0.331.00 mm (small microplastics), 1.014.75 mm (large microplastics), 4.76200 mm (mesoplastic), and .200 mm (macroplastic) (Fig. 1). Materials and Methods Net tow sample collection and analysis Net tows were conducted using neuston nets with a standard mesh size of 0.33 mm towed between 0.5 and 2 m s21 at the sea surface for 1560 minutes outside of the vessels wake to avoid downwelling of debris. Samples were preserved in 5% formalin. Using a dissecting microscope, microplastic was manually separated from natural debris, sorted through stacked Tyler sieves into three size classes [7, 10, 12], then counted individually and weighed together. During sample analysis the identity of smaller microplastics was confirmed with buoyancy and hardness tests. All items were counted and weighed to (...truncated)