All publications

• Modelling the cleanup of the North Pacific Garbage Patch based on 3 years of operational experience

  March 2026, article in a peer review,
  Scientific Reports

  Bruno Sainte-Rose, Laurent Lebreton, Yannick Pham, Arjen Tjallema and Christophe Maes

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  • Publication type: Article in a peer review
  • Publication journal : Scientific Reports
  • Publication date: March 2026
  • Collaborators : The Ocean Cleanup, Rotterdam, The Netherlands, The Modelling House, Raglan, New Zealand, Université de Bretagne Occidentale, IRD, Brest, France
  • DOI: https://doi.org/10.1038/s41598-026-40859-y

  Abstract

  Not available

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• Greenhouse gas emissions from plastic photodegradation: state of knowledge and future directions

  February 2026, article in a peer review,
  journal Environmental Research Letters

  S J Royer and X Zhu

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  • Publication type: Article in a peer review
  • Publication journal : Environmental Research Letters
  • Publication date: February 2026
  • Collaborators : The Ocean Cleanup, Department of Ocean Sciences, Memorial University of Newfoundland, St. John’s, NL, Canada
  • DOI: 10.1088/1748-9326/ae3d4e

  Abstract

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• Marine plastic debris as a reservoir and vector of antibiotic-resistant pathogens: evidence of transmission to sea turtles in the Southwest Indian Ocean

  December 2025, article in a peer-reviewed journal
  Marine Environmental Research

  Philippe Jourand, Alice Philippe, Loris Carret, Shiva Moutoucomarapoule, Celia Crespel, Leila Leon, Loik Sababadichetty, Margot Thibault, Clarisse Majorel, François Guilhaumon, Véronique Lenoble, Claire Jean, Stéphane Ciccione, Mathieu Barret, Francis Schneider and Guillaume Miltgen

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  • Publication type: article in a peer-reviewed journal
  • Publication journal: Marine Environmental Research
  • Publication date: December 2025
  • Collaborators: IRD, UMR ENTROPIE, Saint Denis, La Réunion, France Université de La Réunion, UMR ENTROPIE, Saint Denis, La Réunion, France IUT / Université de La Réunion, Saint-Pierre, La Réunion, France Laboratoire de Bactériologie, CHU Félix Guyon, Saint-Denis, La Réunion, France Université de La Réunion, UMR PIMIT (Processus Infectieux en Milieu Insulaire Tropical), CNRS, Ste Clotilde, La Réunion, France The Ocean Cleanup, Rotterdam, the Netherlands IRD, UMR ENTROPIE, Nouméa, Nouvelle-Calédonie, France Université de Toulon, Aix Marseille Université, CNRS, IRD, UMR MIO, Toulon, France Kelonia, Observatoire des Tortues Marines de l’Ile de La Réunion, Saint-Leu, La Réunion, France Vetorun Selars, Laboratoire vétérinaire, Saint Pierre, La Réunion, France Centre Régional en Antibiothérapie (CRAtb) de La Réunion, Saint-Pierre, La Réunion, France
  • DOI: 10.1016/j.marenvres.2025.107822

  Abstract

  Marine plastic debris provides a novel substrate for microbial colonization, potentially facilitating the spread of pathogens in marine environments. At Reunion Island (Southwest Indian Ocean), injured sea turtles undergoing rehabilitation at the Kélonia center were found to harbor antibiotic-resistant pathogenic bacteria. We hypothesized that these bacteria were originated from plastic debris present in the seawater pumping system. To investigate this, we isolated and characterized culturable bacteria from plastic fragments, seawater, and turtles. Bacterial identification was performed using 16S rDNA sanger sequencing, and multilocus phylogenetic analyses were conducted to assess genetic relatedness among isolates. Antimicrobial susceptibility testing (AST) was also carried out. Plastic debris, primarily composed of polypropylene and polyethylene, supported dense bacterial communities (1e5–1e7 CFU/g), in contrast to seawater which contained significantly lower loads (up to 1e3 CFU/ml). Among the potentially pathogenic bacteria, Enterococcus (22 %), Vibrio (16 %), Bacillus (16 %), Staphylococcus (9 %), and Citrobacter (6 %) were the most prevalent. Phylogenetic analyses revealed close relationships between strains from plastics and turtles, particularly for Bacillus, Citrobacter, and Enterococcus. Notably, Vibrio strains were undetected from seawater but detected on plastics and in turtles, suggesting a possible transmission route. Phenotypic antibiotic resistances, mainly to β-lactams, were detected in 30 % of plastic-associated strains and 14 % of turtle strains. Our results suggest that plastic debris serve as a reservoir and vector for antimicrobial-resistant pathogens, potentially compromising turtle rehabilitation efforts. This potential transmission pathway may hinder the treatment of infected or injured turtles, posing a significant challenge to the conservation of these endangered species.

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• “Where have the sand turtles gone?”: A Waimānalo orientation to plastics research

  November 2025, article in a peer-reviewed journal
  Cambridge Prisms: Plastics

  Johanna Kapōmaikaʻi Stone, Astrid E. Delorme, Kimeona Kāne, Rufino Varea and Ethan Chang and Waimānalo

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  • Publication type: article in a peer-reviewed journal
  • Publication journal: Cambridge Prisms: Plastics
  • Publication date: November 2025
  • Collaborators: Kawaihuelani, University of Hawaiʻi at Mānoa, Honolulu, HI, USA; Research and Technology Development Unit, Ifremer, Plouzane, France; Center for Marine Debris Research, Hawaiʻi Pacific University, Honolulu, HI, USA; The Ocean Cleanup, Rotterdam, Netherlands; He pulapula o Waimānalo, Koʻolaupoko, Honolulu, HI, USA; Office of the Secretariat, Pacific Islands Climate Action Network, Suva, Fiji; College of Education, University of Hawaiʻi at Mānoa, Honolulu, HI, USA Waimānalo, Koʻolaupoko, Honolulu, HI, USA
  • DOI: 10.1017/plc.2025.10033

  Abstract

  This perspective article invites readers to (re)imagine research as a means of practicing right relations with the places we inhabit and descend from. We anchor our work in a Kanaka Hawaiʻi, a Native Hawaiian cosmogeny and epistemology, one that recognizes all life as kin. We begin with the central question, “Where have the sand turtles gone?” to explore how a Kanaka Hawaiʻi-informed perspective, grounded in the genealogical creation chant, ke Kumulipo, can guide plastics research in Hawaiʻi. We elaborate this perspective through a moʻolelo, a story of a collaboration between a Kanaka Hawaiʻi cultural practitioner and a French and Swedish plastics researcher along the shores of Kapua, Waimānalo. By tracing the transformation of a conventional scientific study, we aim to grow entry points for research that is accountable to the place and the genealogical descendants of those specific lands, who have inherited the privilege and responsibility to steward them. We conclude by discussing how this perspective might offer critical insights for global environmental policy, such as the UN Plastic Treaty, urging a shift from treating Indigenous Peoples as stakeholders to honoring them as rights-holders. Ultimately, this work is a call to research in ways that honor the original peoples of the places where we are blessed to live, work, and research, particularly in ways that amplify the knowledge traditions and lifeways birthed from those specific lands. We write this piece for and with Waimānalo as a living, reciprocal co-author. We hope the experiences shared here return to and strengthen those places and people.

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• Highly engaged marine users can help monitor marine plastic pollution in under accessed environments

  October 2025, article in a peer-reviewed journal
  Ocean & Coastal Management

  Peter S. Puskic, Isabelle Cramer, Emma Church, Emily Deery, Matthias Egger, Natalie Fox, William P. de Haan, Laurent Lebreton, Arianna Liconti, Anna Sanchez-Vidal and Helen Wolter

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  • Publication type: article in a peer-reviewed journal
  • Publication journal: Ocean & Coastal Management
  • Publication date: October 2025
  • Collaborators: The Ocean Cleanup, Rotterdam, the Netherlands The Centre for Marine Socioecology, Hobart, Australia The Institute for Marine and Antarctic Studies, Hobart, Australia PADI AWARE Foundation, Bristol, United Kingdom Empaqtify, St. Gallen, Switzerland Ocean Literacy Observatory - MARE | NOVA, Lisbon, Portugal GRC Geociències Marines, Universitat de Barcelona, Barcelona, Spain The Modelling House, Raglan, New Zealand OutBe, Genova, Italy
  • DOI: 10.1016/j.ocecoaman.2025.107983

  Abstract

  Citizen and community science programs have been instrumental to generating large datasets in natural sciences, while simultaneously engaging participants in science and the environment. Community led and citizen science projects have seen broad application to plastic pollution monitoring and cleanup efforts due to the abundance of plastic pollution in all environments around the globe. Here we highlight the work of a niche group of community scientists, we call, highly engaged marine users. This group of community scientists demonstrate a high level of connection to, and understanding of the ocean and are equipped with a set of specific skills and knowledge that are required for their work. We present case studies regarding plastic pollution monitoring by highly engaged marine users working in three understudied marine environments (1) surfers, paddleboarders, and kayakers in the nearshore environment, (2) recreational divers at the seafloor, and (3) recreational and professional seafarers in the open ocean. We reflect on the success of these programs highlighting the role of scientists in providing support in the study design, and execution of project efforts. We demonstrate that highly engaged marine users are key to executing plastic pollution monitoring in understudied marine environments across the globe and that engaging this group will be pivotal in meeting global needs of monitoring marine debris across the global ocean.

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• Plastic pollution: A potential vector of both pathogens and probiotics for corals on the Mascarene Ridge, Indian Ocean

  October 2025, article in a peer-reviewed journal
  Deep Sea Research Part II: Topical Studies in Oceanography

  Vyctoria Marillac, Philippe Jourand, Pierre-Louis Stenger, Gwennais Fustemberg, Julie Gindrey and Margot Thibault

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  • Publication type: Article in a peer-reviewed journal
  • Publication journal: Deep Sea Research Part II: Topical Studies in Oceanography
  • Publication date: October 2025
  • Collaborators: Association BESTRUN, Sainte Clotilde, La Réunion, France UMR ENTROPIE (IRD, CNRS, IFREMER), Université de La Réunion, France Omicsphere Analytics, Montbazon, France The Ocean Clean Up, Rotterdam, the Netherlands
  • DOI: 10.1016/j.dsr2.2025.105556

  Abstract

  In marine environments, plastic debris serves as a vector for pathogenic bacteria that can negatively impact marine fauna, including corals. The Saya de Malha and Nazareth Banks, located in the Indian Ocean, harbor an extensive area of coral reefs that may be susceptible to diseases associated with plastic pollution. In this context, we aimed to determine whether plastic debris in this region can act as a vector for coral-associated pathogenic bacteria. During the “Indian Ocean mission 2022,” floating plastic debris (>500 μm) was collected from the Saya de Malha region using manta trawling. The collected debris were quantified, classified by type, size, and weighed. The associated microbiome, along with the viable bacterial communities attached to the plastic, were analyzed using 16S rDNA high-throughput sequencing and traditional molecular and microbiological techniques. A high concentration of plastic debris was recorded both on Saya de Malha and Nazareth Bank, with 105 items.km−2. The mean viable bacterial count was 15,519 ± 9340 CFU/g of plastic debris. Nine bacterial phyla were identified, with Firmicutes (58 % of the total) and Proteobacteria (42 %) being the dominant groups. The bacterial diversity on the plastic was measured at 0.92, including coral pathogens, such as Acinetobacter (27 %), Psychrobacter (2 %), and Pseudomonas (2 %). In addition, probiotic bacteria such as Exiguobacterium (58 %), Rheinheimera (1 %), and Idiomarina (1 %) were also detected. This preliminary study states the presence of both pathogenic and probiotic coral-associated fixed to plastic. Further research is needed to confirm their direct effect on coral reef disease. Nevertheless, these findings add to the growing evidence of the widespread presence of plastic debris floating in the region.

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• Rise velocity of small polyolefin plastics in a seawater tank exposed to natural conditions in Hawai’i

  September 2025, article in a peer-reviewed journal
  Environmental Research Communications

  Sarah-Jeanne Royer, Kayla C Brignac, Ferenc Ronkay, Kellie Teague, Granya Morris, Jennifer Lynch and Laurent Lebreton

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Article in a Peer-Reviewed Journal
  • Publication date: September 2025
  • Collaborators: The OceanCleanup, Rotterdam, The Netherlands Hawai’i Pacific University, Center for Marine Debris Research, HI, United States of America Lehigh University, PA, United States of America Eszterházy Károly Catholic University, Eger, Hungary The Modelling House, Raglan, New Zealand
  • DOI: /10.1088/2515-7620/ae0876

  Abstract

  Floating plastic is ubiquitous at the ocean surface, but the transport mechanisms associated with the type of particle and the effect of environmental parameters, including the presence of a biofilm on the polymers, are very limited. The type, shape of the particles, as well as the presence of a biofilm affect the plastic object’s buoyancy and alter the effect of photodegradation, hence impacting the distribution and sinking behaviors of discarded plastics in the marine environment. In this study, we assess the effect of the surface area to volume ratio and of biofouling on the rise velocity of positively buoyant polyolefins in the water column in environmentally relevant marine conditions. To establish the parameters that influence the transport of plastics and enhances their removal from surface waters, we conducted a long-term monitoring experiment within a flow-through aquaculture system on O’ahu, Hawai‘i, using high-density polyethylene (HDPE), low-density polyethylene (LDPE), and polypropylene (PP) of three different microplastic sizes and shapes (films, rods, and cubes). Rise velocity results show that HDPE is more prone to remain suspended in the water column compared to LDPE and PP, and that across all three polymers tested, the films and smaller particles have the slowest rise velocity rates compared to rods and cubes of small, medium, and large sizes. When considering the different shapes and sizes, the surface area to volume ratio shows the greatest influence on rise velocity. In addition, the results demonstrate that biofilms positively influence the sinking behaviors of floating polymers when comparing treatments exposed and not exposed to seawater. This study provides some of the first empirical data that can be incorporated into numerical models assessing parameters influencing plastic rise velocities of various shapes and sizes to assist in more accurate predictions of the fate and transport of positively buoyant plastics in the ocean.

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• Investigating metal distribution patterns in pristine and ocean-weathered plastics using LA-ICP-TOFMS

  September 2025, Article in a Peer-Reviewed Journal
  Journal of analytical atomic spectrometry

  Lyndsey Hendriks, Matthias Egger and Denise M. Mitrano

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  • Journal: Journal of analytical atomic spectrometry
  • Publication type: Article in a Peer-Reviewed Journal
  • DOI: 10.1039/D5JA00223K

  Abstract

  Plastic pollution in marine environments poses ecological risks, in part because plastic debris can release hazardous substances, such as metal-based additives. While microplastics have received considerable attention as vectors of contaminants, less is known about larger macroplastics and their role in the spatial and temporal redistribution of substances. In this study, pristine, store-bought plastic items and macroplastics recovered from the North Pacific Subtropical Gyre (NPSG) were analysed using Fourier-Transform Infrared Spectroscopy (FTIR) to identify polymer types, and bulk acid digestion followed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for total metal quantification. These techniques were complemented by high resolution elemental mapping by Laser Ablation Inductively Coupled Plasma Time-of-Flight Mass Spectrometry (LA-ICP-TOFMS). Detailed elemental maps revealed native metal distribution in pristine plastics, and evidence of both sorption and intrinsic metal depletion in weathered plastics. In particular, weathered plastics showed surface depletion of intrinsic metals, and enrichment of seawater-derived elements (e.g., Na, Mg, I). Linear regressions were used to quantify spatial distribution trends across cross sections, providing statistical support for directional gradients. Since pristine and weathered plastics were opportunistically collected, variability in product type, polymer chemistry, and weathering time limited direct comparisons. Instead, this study demonstrates the utility of LA-ICP-TOFMS for mapping elemental distribution in plastics, offering a novel analytical approach for investigating spatial metal distribution in plastics and laying the groundwork for future studies on weathering processes in marine environments.

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• Concentration gradient of plastic debris larger than 500 μm detected across the Southwest Indian ocean

  July 2025, Article in a Peer-Reviewed Journal
  Scientific Reports

  Margot Thibault, Adrian Fajeau, Aina Ramanampananjy, Sarah-Jeanne Royer, Gwennaïs Fustemberg, Vyctoria Marillac, Julie Gindrey, Anjara Saloma, Manon Condet, Perrine Mangion, April Burt, Matthias Egger, Maxime Amy, Sébastien Jaquemet, Thierry Mulochau, Philippe Jourand, Alexandra ter Halle, Matthieu Le Corre and Laurent Lebreton

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  • Journal: Scientific Reports
  • Publication type: Article in a Peer-Reviewed Journal
  • DOI: 10.1038/s41598-025-02893-0

  Abstract

  Marine plastic pollution is increasing in the world’s ocean, with the Indian Ocean understudied compared to the Pacific and Atlantic Oceans. This study investigates plastic pollution in the Southwest Indian Ocean, focusing on a size range from large debris to microplastics (> 500 μm). Using visual surveys and manta trawling, we assessed plastic concentrations, compositions, and polymer types across 19 oceanographic campaigns. A total of 11,438 litter items were identified, with over 70% consisting of plastics. Larger plastic debris was predominantly observed near Glorieuses Islands during visual surveys, while microplastics were more prevalent offshore, collected through manta trawling. We observed a gradient of increasing plastic concentrations along the 30°/33°S latitudes, from 40°E (macroplastics: 10 items/km²; microplastics: 103 items/km²) to 65°E (macroplastics: 102 items/km²; microplastics: 105 items/km²). The majority of plastic debris consisted of hard fragments, primarily polyethylene (45.7%) and polypropylene (26.7%). Our findings provide new insights into microplastic concentrations in offshore regions, highlight the significant degradation of plastic debris, and emphasize the need for further research to identify and map the Indian Ocean’s garbage patch along these latitudes. Keys words: Indian Ocean, Marine litter, Visual survey, Manta trawling, Microplastics.

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• Oceanic regions shape the composition of the Antarctic plastisphere

  June 2025, Article in a Peer-Reviewed Journal
  Communications Earth & Environment

  Ana L. Lacerda, Maíra C. Proietti, Felipe Kessler, Carlos R. Mendes, Eduardo R. Secchi and Joe D. Taylor

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  • Journal: Communications Earth & Environment
  • Publication type: Article in a Peer-Reviewed Journal
  • DOI: 10.1038/s43247-025-02445-4

  Abstract

  Antarctica, once considered pristine, is increasingly threatened by plastic pollution, with debris found in its waters, sediments, sea ice, and biota. Here, we provide a comprehensive molecular survey of both prokaryotic and eukaryotic diversity on plastics around the Antarctic Peninsula, addressing a gap in existing research. Using eDNA metabarcoding, we identified diverse communities, with Pseudomonadota and Bacteroidota dominating prokaryotic communities, while Gyrista (mostly diatoms), Fungi and Arthropods were prevalent among eukaryotes. Geographic location significantly influenced community composition, with differences between the Bransfield Strait and the Gerlache Strait/Bellingshausen Sea. Polymer type and plastic shape did not impact species richness or community structure. These findings offer new insights into the complexity of the Antarctic plastisphere, highlighting potential impacts on biodiversity, ecosystem functions, and the broader implications of marine plastic pollution.

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• Assessing Plastic Brittleness to Understand Secondary Microplastic Formation on Beaches: A Hotspot for Weathered Marine Plastics

  June 2025, Article in a Peer-Reviewed Journal
  Microplastics and Nanoplastics

  Astrid E. Delorme, Laurent Lebreton, Sarah-Jeanne Royer, Kimeona Kāne, Mael Arhant, Maelenn Le Gall and Pierre-Yves Le Gac

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  • Journal: Microplastics and Nanoplastics
  • Publication type: Article in a Peer-Reviewed Journal
  • Collaborators: Ifremer RDT, Research and Technology Development Unit, Plouzané, France Center for Marine Debris Research, Hawaiʻi Pacific University, Waimānalo, HI, USA The Ocean Cleanup, Rotterdam, The Netherlands The Modelling House Limited, Raglan, New Zealand Community Scholar, Cultural Practitioner, Chairperson of the Waimānalo Neighborhood Board, Waimānalo, HI, USA
  • DOI: 10.1186/s43591-025-00128-7

  Abstract

  The degradation and fragmentation of plastic debris into secondary microplastics pose significant environmental challenges, particularly on beaches where mechanical abrasion and chemical weathering accelerate plastic fragmentation. This study contributes to the understanding of secondary microplastic formation by addressing key questions related to plastic embrittlement, mechanical behavior, and degradation processes. We investigate the brittleness of polyethylene (PE) and polypropylene (PP) particles collected from Hawaiian beaches, focusing on their mechanical and chemical degradation states. Conventional tensile testing methods are impractical for irregularly shaped, small field-recovered particles. Therefore, we used a simple fragmentation test to evaluate brittleness under fixed applied pressure, enabling large-scale statistical analysis of PE and PP samples from beach field surveys. We show that the brittle samples have a very low molecular weight (Mw). Such low Mw, coupled with the appearance of oxidation products, suggests an advanced degradation state of the sampled plastics. Through our fragmentation test, we provide a large-scale, field-based quantification of plastic brittleness in beach samples, underscoring an increased propensity for further fragmentation and highlighting the severity of coastal and ocean plastic pollution.

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• Evaluating the environmental impact of cleaning the North Pacific Garbage Patch

  May 2025, Article in a Peer-Reviewed Journal
  Scientific Reports

  Matthias Egger, Andy M. Booth, Thijs Bosker, Gert Everaert, Samantha L. Garrard, Vilma Havas, Helga S. Huntley, Albert A. Koelmans, Karin Kvale, Laurent Lebreton, Helge Niemann, Qiaotong Pang, Maira Proietti, Peter Puskic, Camille Richon, Sarah-Jeanne Royer, Matthew S. Savoca, Arjen Tjallema, Marjolein van Vulpen, Yanxu Zhang, Ziman Zhang and Denise M. Mitrano

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  • Journal: Scientific Reports
  • Publication type: Article in a Peer-Reviewed Journal
  • Collaborators: The Ocean Cleanup in Rotterdam, The Netherlands; Empaqtify in St. Gallen, Switzerland; SINTEF Ocean in Trondheim, Norway; Leiden University in The Netherlands; the Flanders Marine Institute in Belgium; Plymouth Marine Laboratory in the UK; Salt Lofoten and Aalborg University in Norway and Denmark respectively; Rowan University in the USA; Wageningen University in The Netherlands; GNS Science and Aotearoa Blue Ocean Research in New Zealand; The Modelling House Limited in New Zealand; NIOZ Royal Netherlands Institute for Sea Research and Utrecht University in The Netherlands; Nanjing University in China; Universidade Federal do Rio Grande in Brazil; the University of Tasmania and the Center for Marine Socioecology in Australia; CNRS, Ifremer, IRD, LEMAR, and University Brest in France; Stanford University and the California Marine Sanctuary Foundation in the USA; Tulane University in the USA; and the Swiss Federal Institute of Technology (ETH) Zurich in Switzerland.
  • Publication date: May 27, 2025
  • DOI: 10.1038/s41598-025-00619-w

  Abstract

  Cleanup of existing plastic pollution is crucial to mitigate its impact on marine ecosystems, but such efforts must ensure benefits outweigh potential environmental damage caused by the cleanup. Here, we present an impact assessment framework and apply it to evaluate whether cleaning the North Pacific Garbage Patch (NPGP) benefits marine life and carbon cycling, using The Ocean Cleanup as a case study. Our findings indicate that marine life is more vulnerable to plastic pollution than to macroplastic cleanup, with average vulnerability scores (1 = low, 3 = high) of 2.3 for macroplastics, 1.9 for microplastics, and 1.8 for cleanup, suggesting a net positive impact. An 80% cleanup could reduce macroplastic concentrations to within reported safe levels for marine mammals and sea turtles. Estimated cleanup-related carbon emissions [0.4–2.9 million metric tons (Mt) in total] are significantly lower than potential long-term microplastics impacts on ocean carbon sequestration (15–30 Mt C per year). However, uncertainties remain regarding effects on air-sea carbon exchange. Our framework serves as a critical tool for assessing trade-offs between plastic pollution and remediation impacts. It demonstrates the environmental net benefits of the proposed NPGP cleanup and can be adapted to similarly evaluate other remediation plans.

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• The distribution of subsurface microplastics in the ocean

  April 2025, article in a peer reviewed Journal
  Nature

  Shiye Zhao, Karin F. Kvale, Lixin Zhu, Erik R. Zettler, Matthias Egger, Tracy J. Mincer, Linda A. Amaral-Zettler, Laurent Lebreton, Helge Niemann, Ryota Nakajima, Martin Thiel, Ryan P. Bos and Luisa Galgani & Aron Stubbins

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  • Journal: Nature
  • Publication type: article in a peer-reviewed Journal
  • Collaborators: Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan. Aotearoa Blue Ocean Research, Lower Hutt, New Zealand. State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China. Department of Marine and Environmental Sciences, Northeastern University, Boston, MA, USA. NIOZ Royal Netherlands Institute for Sea Research, Den Burg, The Netherlands. The Ocean Cleanup, Rotterdam, The Netherlands. Empaqtify, St Gallen, Switzerland. Harriet Wilkes Honors College, Florida Atlantic University, Boca Raton, FL, USA. Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands. Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands. Facultad Ciencias del Mar, Universidad Catolica del Norte, Coquimbo, Chile. MarineGEO Program, Smithsonian Environmental Research Center, Edgewater, MD, USA. Centre for Ecology and Sustainable Management of Oceanic Island (ESMOI), Coquimbo, Chile. Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA. Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy. National Biodiversity Future Center (NBFC), Palermo, Italy. Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA. Department of Civil and Environmental Engineering, Northeastern University, Boston, MA, USA.
  • Publication date: April 30, 2025
  • DOI: 10.1038/s41586-025-08818-1

  Abstract

  Marine plastic pollution is a global issue, with microplastics (1 µm–5 mm) dominating the measured plastic count. Although microplastics can be found throughout the oceanic water column, most studies collect microplastics from surface waters (less than about 50-cm depth) using net tows. Consequently, our understanding of the microplastics distribution across ocean depths is more limited. Here we synthesize depth-profile data from 1,885 stations collected between 2014 and 2024 to provide insights into the distribution and potential transport mechanisms of subsurface (below about 50-cm depth, which is not usually sampled by traditional practices) microplastics throughout the oceanic water column. We find that the abundances of microplastics range from 1e−4 to 1e4 particles per cubic metre. Microplastic size affects their distribution; the abundance of small microplastics (1 µm to 100 µm) decreases gradually with depth, indicating a more even distribution and longer lifespan in the water column compared with larger microplastics (100 µm to 5,000 µm) that tend to concentrate at the stratified layers. Mid-gyre accumulation zones extend into the subsurface ocean but are concentrated in the top 100 m and predominantly consist of larger microplastics. Our analysis suggests that microplastics constitute a measurable fraction of the total particulate organic carbon, increasing from 0.1% at 30 m to 5% at 2,000 m. Although our study establishes a global benchmark, our findings underscore that the lack of standardization creates substantial uncertainties, making it challenging to advance our comprehension of the distribution of microplastics and its impact on the oceanic environment

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• A year-long field study of buried plastics reveals underestimation of plastic pollution on Hawaiian beaches

  February 2025, article in a peer reviewed Journal
  Marine Pollution Bulletin

  Astrid E. Delorme, Olivier B. Poirion, Laurent Lebreton, Pierre-Yves le Gac, Kimeona Kāne and Sarah-Jeanne Royer

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  • Journal: Marine Pollution Bulletin
  • Publication Type: Article in a peer reviewed journal
  • Collaborators: Ifremer, Plouzané, France Hawaiʻi Pacific University, Honolulu, United States of America The Ocean Cleanup, Rotterdam, the Netherlands The Jackson Laboratory, Farmington, United States of America The Modelling House Limited, Raglan, New Zealand Waimānalo Neighborhood Board, Honolulu, United States of America
  • Publication date: February 27, 2025
  • DOI: 10.1016/j.marpolbul.2025.117712

  Abstract

  Global models estimate that two-thirds of floating ocean plastic has accumulated in coastal areas since the 1950s, with Hawaiʻi’s windward shores particularly vulnerable due to their proximity to the North Pacific Garbage Patch. Our quarterly surveys revealed that 91 % of recovered plastic particles were buried below the surface (deeper than 2 cm), with most particles being small fragments (93 %) with an average mean max length of 6.7 ± 4.4 mm. This study offers new insights into subsurface plastic, exposing a previously hidden vertical distribution of plastic pollution. We observed significant variations in plastic abundance across depths, beaches, and sampling periods, along with a positive correlation between particle size and sand grain size. Additionally, through reconciliation science, we critically reflect on the cultural impacts of our research, emphasizing the importance of aligning plastic pollution studies with local community values and environmental stewardship.

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• The tidal trap — Seasonal transport of floating macrodebris in the bi-directional Chao Phraya River network on the Gulf of Thailand

  January 2025, article in a peer reviewed Journal
  Marine Pollution Bulletin

  Thomas Mani, Ronja Ebner, Laurent Lebreton, Pummarin Khamdahsag, Doungkamon Phihusut, Yotwadee Hawangchu, Jenyuk Lohwacharin and Ratchanon Piemjaiswang

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  • Publication journal: Marine Pollution Bulletin
  • Publication type: article in a peer-reviewed journal
  • Collaborators: The Ocean Cleanup, Rotterdam, the Netherlands The Modelling House, Raglan, New Zealand Sustainable Environment Research Institute, Chulalongkorn University, Bangkok, Thailand Office of National Higher Education Science Research and Innovation Policy Council, Bangkok, Thailand Aquatic Resources Research Institute, Chulalongkorn University, Bangkok, Thailand Department of Environmental and Sustainable Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand
  • Publication date: January 27, 2025
  • DOI: DOI: 10.1016/j.marpolbul.2025.117605

  Abstract

  Models estimate up to 3 million metric tons of river plastic waste flowing into the world’s ocean every year. All ocean-bound rivers endure tidal impact to some degree, but there is a lack of data on the resulting marine emission effects. To address this gap, we analyzed the trajectories of grapefruit-sized floating GPS drifters (n = 63) in the Chao Phraya estuary in Bangkok, Thailand, in the three seasons of 2022–2023. We observe considerable bi-directional drifter oscillation over dozens of kilometers in all seasons with particles transitioning in and out of urban canals. The only substantial net downstream transport towards the ocean occurred in the rainy season (May–Oct). Only one drifter reached the sea. We further show that drifters are more likely to travel through the center and outside portion of river bends. Besides advancing models this study provides spatiotemporal insights for water pollution mitigation and cleanup policies.

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• Optimizing the Path Towards Plastic-Free Oceans

  December 2024, article in a peer reviewed Journal
  Operations Research

  Dick den Hertog, Jean Pauphilet, Yannick Pham, Bruno Sainte-Rose and Baizhi Song

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  • Publication journal: Operations Research
  • Publication type: Article in a peer reviewed Journal
  • Collaborators: The Ocean Cleanup, Rotterdam, The Netherlands
  • Publication date: December 11, 2024
  • DOI: 10.1287/opre.2023.0515

  Abstract

  Increasing ocean plastic pollution is irreversibly harming ecosystems and human economic activities. We partner with a nonprofit organization and use optimization to help clean up oceans from plastic faster. Specifically, we optimize the route of their plastic collection system in the ocean to maximize the quantity of plastic collected over time. We formulate the problem as a longest path problem in a well-structured graph. However, because collection directly impacts future plastic density, the corresponding edge lengths are nonlinear polynomials. After analyzing the structural properties of the edge lengths, we propose a search-and-bound method, which leverages a relaxation of the problem solvable via dynamic programming and clustering, to efficiently find high-quality solutions (within 6% optimal in practice) and develop a tailored branch-and-bound strategy to solve it to provable optimality. On one year of ocean data, our optimization-based routing approach increases the quantity of plastic collected by more than 60% compared with the current routing strategy, hence speeding up the progress toward plastic-free oceans.

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• Aging of plastics and microplastics in the environment: a review on influencing factors, quantification methods, challenges, and future perspectives

  December 2024, article in a peer-reviewed journal
  Environmental Science and Pollution Research

  Merin Grace Baby, Jan Gerritse, Ana Beltran-Sanahuja, Helen Wolter, Sébastien Rohais and Maria-Fernanda Romero-Sarmiento

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  • Journal: Environmental Science and Pollution Research
  • Publication Type: article in a peer-reviewed journal
  • Collaborators:: IFP Énergies Nouvelles (IFPEN), Rueil-Malmaison, France Deltares, Utrecht, The Netherlands University of Alicante, Alicante, Spain The Ocean Cleanup, Rotterdam, The Netherlands
  • Publication date: December 12, 2024
  • DOI: 10.1007/s11356-024-35651-2

  Abstract

  The ubiquitous presence of fragmented plastic particles needs comprehensive understanding of its fate in the environment. The long-term persistence of microplastics (MPs) in the environment is a significant threat to the ecosystem. Even though various degradation mechanisms (physical, chemical, and biological) of commonly used plastics have been demonstrated, quantifying the degradation of MPs over time to predict the consequence of plastic littering and its persistence in the environment remains a challenge. Different advanced analytical techniques have been used to quantify the degradation of MPs by introducing various parameters such as bond indices, crystallinity, and carbon–oxygen ratio. However, a simple and widely accepted reliable methodology for comparing the environmental factors and their influence on the MP degradation has yet to be developed and validated. This paper reviews a section of relevant literature (n = 38) to synthesize an overview of methods implemented for the quantification of fragmentation and aging of MPs in natural and artificial environment. In addition, the inherent weakness and extrinsic factors affecting the degradation of MPs in the environment is discussed. Finally, it proposes challenges and future scope as guideline for research on MP degradation in the environment.

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• Transient Attracting Profiles in the Great Pacific Garbage Patch

  December 2024, article in a peer reviewed Journal
  European Geosciences Union

  Luca Kunz, Alexa Griesel , Carsten Eden, Rodrigo Duran and Bruno Sainte-Rose

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  • Publication journal: European Geosciences Union
  • Publication type: Article in a peer reviewed Journal
  • Collaborators: The Ocean Cleanup, Rotterdam, The Netherlands
  • Publication date: December 5, 2024
  • DOI: 10.5194/os-20-1611-2024

  Abstract

  A major challenge for cleanup operations in the Great Pacific Garbage Patch is the daily prediction of plastic concentrations that allows identifying hotspots of marine debris. Lagrangian simulations of large particle ensembles are the method in use and effectively reproduce observed particle distributions at synoptic scales 𝒪(1000 km). However, they lose accuracy at operational scales 𝒪(1–10 km), and operators regularly experience differences between predicted and encountered debris accumulations within the garbage patch. In Lagrangian methods, it would be common to ask this question: where do objects go as they follow the current? Here, we take a different approach and instead ask this question: which locations attract material? The recently developed concept of Transient Attracting Profiles (TRAPs) provides answers because TRAPs uncover the most attracting regions of the flow. TRAPs are the attracting form of hyperbolic Objective Eulerian Coherent Structures and are computable from the instantaneous strain field on the ocean surface. They describe flow features which attract drifting objects and could facilitate offshore cleanups that are currently taking place in the Great Pacific Garbage Patch. However, the concept remains unapplied since little is known about the persistence and attraction of these features, specifically within the Pacific. Therefore, we compute a 20-year dataset of daily TRAP detections from satellite-derived mesoscale velocities within the North Pacific subtropical gyre. We are the first to track these instantaneous flow features as they propagate through space and time. It allows us to study the life cycle of TRAPs, which can range from days to seasons and lasts an average of 6 d. We show how long-living TRAPs with lifetimes beyond 30 d intensify and weaken over their life cycle, and we demonstrate that the evolution stage of TRAPs affects the motion of nearby surface drifters. Our findings indicate that, at the mesoscale, operators in the Great Pacific Garbage Patch should search for long-living TRAPs that are at an advanced stage of their life cycle. These TRAPs are the most likely to induce a large-scale confluence of drifting objects and their streamlining into hyperbolic pathways. Such a streamlined bypass takes, on average, 5 d and creates an opportunity to filter the flow around TRAPs. But we also find TRAPs that retain material over multiple weeks where we suspect material clustering at the submesoscale. Prospective research could investigate this further by applying our algorithms to soon-available high-resolution observations of the flow. Our analysis contributes to a better understanding of TRAPs, which can even benefit other offshore operations besides ocean cleanups, such as optimal drifter deployment, oil spill containment, and humanitarian search and rescue.

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• Mind the fragmentation gap

  November, 2024, article in peer-reviewed journal
  Nature Communications

  Karin Kvale, Zhenna Azimrayat Andrews and Matthias Egger

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  • Publication journal: Nature Communications
  • Publication type: Article in peer-reviewed journal
  • Collaborators: GNS Science, Lower Hutt, New Zealand | Aotearoa Blue Ocean Research, Lower Hutt, New Zealand | University of Cambridge, Cambridge, UK | The Ocean Cleanup, Rotterdam, The Netherlands | Egger Research and Consulting, St, Gallen, Switzerland
  • Publication date: November 13, 2024
  • DOI: 10.1038/s41467-024-53962-3

  Abstract

  The Global Plastics Treaty presents an opportunity to “end plastic pollution”. Legacy plastics will continue to fragment to secondary microplastics for decades, without additional mitigation measures. We identify this flux as a “fragmentation gap”, currently overlooked in global policy targets.

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• Wasted shores: Using drones to monitor the spatio-temporal evolution of debris accumulation hotspots on South Africa’s Umgeni River

  October, 2024, article in peer-reviewed journal
  Science of The Total Environment

  Tadiwanashe Gutsa, Cristina Trois, Robin de Vries and Thomas Mani

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  • Publication journal: Science of The Total Environment
  • Publication type: Article in peer-reviewed journal
  • Collaborators: Civil Engineering, School of Engineering, University of KwaZulu-Natal, Durban, South Africa | Centre for Renewable and Sustainable Energy Studies, Faculty of Engineering, Stellenbosch University, South Africa | The Ocean Cleanup, Rotterdam, the Netherlands
  • Publication date: October 9, 2024
  • DOI: 10.1016/j.scitotenv.2024.176791

  Abstract

  Rivers are major contributors of plastic waste to the oceans. Running through the northern part of the 1.3 million-inhabitants City of Durban, South Africa, the Umgeni River is estimated to flush in the order of tens to hundreds of tonnes of plastic waste into the Indian Ocean every year. The riverbanks are lined with plastic and other macro-waste accumulation zones formed due to direct littering and occasional deposition of river debris loads. This study presents the use of Unmanned Aerial Vehicles (UAVs) and hydro-meteorological sensors to (1) identify, quantify and monitor such anthropogenic macro-waste hotspots; and (2) investigate the influence of rainfall, river water level and a major flood event on the spatio-temporal evolution of the hotspots, evidencing the debris’ availability to leak into the Indian Ocean. The one-year aerial monitoring (2021−2022) of waste hotspots shows that extreme hydrometeorological events have an immediate but short-term effect on the erosion of debris stocks in riverine systems. We observe that reduction in mean index changes of hotspot surface area after flooding were 2–5 times higher than in non-flood conditions. Despite visual evidence of seasonality in debris erosion between the wet and dry season, only the ‘natural’ type hotspots showed a significant change. Our findings support reported inconsistencies of macro-debris erosion with hydrological factors. Although the data contributes a baseline for macro-debris erosion in the Umgeni River, future ground truth sampling and finer monitoring scales are important to fully understand debris transfer in river systems. The mapping of waste hotspots and understanding their spatio-temporal transfer dynamics supports policymakers in planning and timing to mitigate environmental pollution.

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• Monitoring macroplastics in aquatic and terrestrial ecosystems: Expert survey reveals visual and drone-based census as most effective techniques

  September, 2024, article in peer-reviewed journal
  Science of The Total Environment

  L. Gallitelli, P. Girard, U. Andriolo, M. Liro, G. Suaria, C. Martin, A.L. Lusher, K. Hancke, MCM Blettler, O. Garcia-Garin, I.E. Napper, L. Corbari, A. Cózar, C. Morales-Caselles, D. González-Fernández, J. Gasperi, T. Giarrizzo, G. Cesarini, K. De, M. Constant, P. Koutalakis, G. Gonçalves, P. Sharma, S. Gundogdu, R. Kumar, N.A. Garello, A.L.G. Camargo, K. Topouzelis, F. Galgani, S.J. Royer, G.N. Zaimes, F. Rotta, S. Lavender, V. Nava, J. Castro-Jiménez, T. Mani, R. Crosti, V.M. Azevedo-Santos, F. Bessa, R. Tramoy, M.F. Costa, C. Corbau, A. Montanari, C. Battisti and M. Scalici

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  • Publication journal: Science of The Total Environment
  • Publication type: Article in peer-reviewed journal
  • Collaborators: Department of Sciences, University Roma Tre, Viale Guglielmo Marconi 446, 00146 Rome, Italy | Biosciences Institute, Federal University of Mato Grosso, 78060-900 Cuiabá, MT, Brazil | INESC Coimbra, Department of Electrical and Computer Engineering, Polo 2, 3030-290 Coimbra, Portugal | Institute of Nature Conservation, Polish Academy of Sciences, al. Adama Mickiewicza 33, 31–120 Kraków, Poland | Istituto di Scienze Marine - Consiglio Nazionale delle Ricerche, CNR-ISMAR, Pozzuolo di Lerici, La Spezia, Italy | Red Sea Research Center (RSRC) and Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia | Norwegian Institute for Water Research (NIVA), Oslo, Norway | The National Institute of Limnology (INALI; CONICET-UNL), Ciudad Universitaria, 3000 Santa Fe, Argentina | Department of Evolutionary Biology, Ecology and Environmental Sciences, Biodiversity Research Institute (IRBio), Faculty of Biology, Universitat de Barcelona, 08028 Barcelona, Spain | International Marine Litter Research Unit, University of Plymouth, Plymouth, UK | School of Biological and Marine Sciences, University of Plymouth, Plymouth, UK | Dipartimento di Ingegneria, Università degli Studi di Palermo, Palermo, Italy| Department of Biology, University Marine Research Institute INMAR, University of Cádiz and European University of the Seas SEA-EU, Puerto Real, Spain | Univ Gustave Eiffel, GERS-EE, Campus Nantes, France | Instituto de Ciências do Mar (LABOMAR), Universidade Federal do Ceará (UFC), Fortaleza, Brazil | National Research Council—Water Research Institute (CNR-IRSA), Corso Tonolli 50, 28922 Verbania Pallanza, Italy | Biological Oceanography Division, CSIR- National Institute of Oceanography, Dona Paula, Goa 403004, India | Univ. Lille, Institut Mines-Télécom, Univ. Artois, Junia, ULR 4515 - LGCgE, Laboratoire de Génie Civil et géo-Environnement, F-59000 Lille, France | Geomorphology, Edaphology and Riparian Areas Laboratory (GERi Lab), Department of Forestry and Natural Environment Science, International Hellenic University, University Campus in Drama, 66100 Drama, Greece | University of Coimbra, Department of Mathematics, Coimbra, Portugal | Department of Agricultural Engineering and Technology, School of Engineering and Technology, Nagaland University, Dimapur, Nagaland, India | Cukurova University, Department of Basic Science, Adana, Türkiye | Department of Biosystems Engineering, Auburn University, Auburn, AL 36849, USA | Botany and Ecology Department, Federal University of Mato Grosso (UFMT), Cuiabá, Brazil | Department of Marine Sciences, University of Aegean, Greece | ECHOS D'OCEANS, 20217 Saint Florent, Corse, France | The Ocean Cleanup, Coolsingel 6, 3011 AD Rotterdam, the Netherlands | GERi Lab (Geomorphology, Edaphology and Riparian Area Laboratory), Democritus University of Thrace, Drama, Greece | Department of Earth and Environmental Sciences, University of Pavia, Pavia, Italy | Institute of Earth Sciences, University of Applied Sciences and Arts of Southern Switzerland (SUPSI), Mendrisio, Switzerland | Pixalytics Ltd, Plymouth, UK | Department of Earth and Environmental Sciences, University of Milano-Bicocca, Milano, Italy | IFREMER, CCEM Contamination Chimique des Écosystèmes Marins, F-44000 Nantes, France | ISPRA, Istituto Superiore Protezione e Ricerca Ambientale, Biodiversità, Roma, Italy | Faculdade Eduvale de Avaré, Avaré, São Paulo, Brazil | Centre for Functional Ecology - Science for People & the Planet (CFE), Associate Laboratory TERRA, Department of Life Sciences, University of Coimbra, Portugal | LEESU, Univ Paris Est Créteil, Ecole Des Ponts, Creteil, France | Departamento de Oceanografia da Universidade Federal de Pernambuco, Av. Arquitetura s/n, Cidade Universitária, Recife, Pernambuco CEP 50740-550, Brazil | University of Ferrara, Ferrara, Italy | Department of Civil, Chemical, Environmental and Material Engineering, Via del Risorgimento 2, 40136 Bologna, Italy | National Biodiversity Future Center (NBFC), Università di Palermo, Piazza Marina 61, 90133 Palermo, Italy
  • Publication date: September 25, 2024
  • DOI: 10.1016/j.scitotenv.2024.176528

  Abstract

  Anthropogenic litter, such as plastic, is investigated by the global scientific community from various fields employing diverse techniques. The goal is to assess and finally mitigate the pollutants’ impacts on the natural environment. Plastic litter can accumulate in different matrices of aquatic and terrestrial ecosystems, impacting both biota and ecosystem functioning. Detection and quantification of macroplastics, and other litter, can be realized by jointly using visual census and remote sensing techniques. The primary objective of this research was to identify the most effective approach for monitoring macroplastic litter in riverine and marine environments through a comprehensive survey based on the experiences of the scientific community. Researchers involved in plastic pollution evaluated four litter occurrence and flux investigation methods (visual census, drone-based surveys, satellite imagery, and GPS/GNSS trackers) through a questionnaire. Traditional visual census and drone deployment were deemed as the most popular approaches among the 46 surveyed researchers, while satellite imagery and GPS/GNSS trackers received lower scores due to limited field validation and short performance ranges, respectively. On a scale from 0 to 5, visual census and drone-based surveys obtained 3.5 and 2.0, respectively, whereas satellite imagery and alternative solutions received scores lower than 1.2. Visual and drone censuses were used in high, medium and low-income countries, while satellite census and GPS/GNSS trackers were mostly used in high-income countries. This work provides an overview of the advantages and drawbacks of litter investigation techniques, contributing i) to the global harmonization of macroplastic litter monitoring and ii) providing a starting point for researchers and water managers approaching this topic. This work supports the selection and design of reliable and cost-effective monitoring approaches to mitigate the ambiguity in macroplastic data collection, contributing to the global harmonization of macroplastic litter monitoring protocols.

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• Barau’s petrel, Pterodroma baraui, as a bioindicator of plastic pollution in the South-West Indian Ocean: a multifaceted approach

  August 2024, article in peer-reviewed journal
  Marine Environmental Research

  Margot Thibault, Lisa Weiss, Romain Fernandez, Naïs Avargues, Sébastien Jaquemet, Laurent Lebreton, Juliette Garnier, Audrey Jaeger, Sarah-Jeanne Royer, Audrey Cartraud, Alexandra ter Halle, Patrick Marsaleix, Leo Chevillon, Julie Tourmetz and Matthieu Le Corre

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  • Publication journal: Marine Environmental Research
  • Publication type: Article in peer-reviewed journal
  • Collaborators: The Ocean Cleanup, Rotterdam, The Netherlands | UMR ENTROPIE (Univ. La Réunion, IRD, CNRS, Ifremer, Univ. Nouvelle-Calédonie), 97400, Saint Denis, La Réunion, France | CNRS, Université Toulouse III, Laboratoire des Interactions Moléculaires et Réactivité Chimique et Photochimique (IMRCP), UMR 5623, Toulouse, France | Université de Toulouse, CNRS, IRD, CNES, UPS, Laboratoire d’Etudes en Géophysique et Océanographie Spatiales (LEGOS), F31400 Toulouse, France | Ocea Consult, 97410 Saint Pierre, La Réunion, France | Société d’Etudes Ornithologiques de La Réunion, 97440 Saint-André, France | Université de Brest, CNRS, Ifremer, IRD, Laboratoire d'Océanographie Physique et Spatiale (LOPS), IUEM, F29280, Plouzané, France
  • Publication date: August 29, 2024
  • DOI: /10.1016/j.marenvres.2024.106709

  Abstract

  Marine plastic pollution is well described by bioindicator species in temperate and polar regions but remains understudied in tropical oceans. We addressed this gap by evaluating the seabird Barau’s petrel as bioindicator of plastic pollution in the South-West Indian Ocean. We conducted a multifaceted approach including necropsies of birds to quantify plastic ingestion; GPS tracking of breeding adults to identify their foraging areas; manta trawling of plastic debris to measure plastic pollution at sea and modelling of plastic dispersal. We developed a spatial risk index of seabird exposure to plastic ingestion. Seventy-one percent of the analysed birds had ingested plastic. GPS tracking coupled with manta trawling and dispersal modelling show that adults consistently foraged at places with high level of plastic concentration. The highest ingestion risk occurred in the northwest of Reunion Island and at latitude 30°S. Our findings confirm that Barau’s petrel is a reliable bioindicator of plastic pollution in the region.

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• Plastic ingestion by odontocetes from the Western South Atlantic: A particular concern to a threatened species

  August 2024, article in peer-reviewed journal
  Environmental Pollution

  Marina Zimmer-Correa, Maíra Carneiro Proietti, Juliana Couto Di Tullio, Lucas dos S. Rodrigues, Eliezer Quadro Oreste, Felipe Kessler, Manuela Bassoi and Silvina Botta

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  • Publication journal: Environmental Pollution
  • Publication type: Article in peer-reviewed journal
  • Collaborators: Programa de Pós-Graduação em Oceanografia Biológica, Instituto de Oceanografia, Universidade Federal do Rio Grande - FURG, Rio Grande, Brazil | Laboratório de Ecologia e Conservação da Megafauna Marinha (ECOMEGA), Instituto de Oceanografia, Universidade Federal do Rio Grande - FURG, Rio Grande, Brazil | Projeto Lixo Marinho, Instituto de Oceanografia, Universidade Federal do Rio Grande - FURG, Rio Grande, Brazil | The Ocean Cleanup, Rotterdam, the Netherlands | Laboratório de Dinâmica Populacional Pesqueira, Instituto de Oceanografia, Universidade Federal do Rio Grande - FURG, Rio Grande, Brazil | Departament d'Estadística i Investigació Operativa, Universitat de València, Valencia, Spain | Laboratório de Físico-Química Aplicada e Tecnológica (LAFQAT), Escola de Química e Alimentos, Universidade Federal do Rio Grande - FURG, Rio Grande, Brazil | Laboratório de Bioacústica (LaB), Centro de Biociências, Universidade Federal do Rio Grande do Norte - UFRN, Natal, Brazil.
  • Publication date: August 7, 2024
  • DOI: /10.1016/j.envpol.2024.124659

  Abstract

  The ingestion of debris by marine fauna is a growing threat to biodiversity. This study aimed to evaluate and characterize litter ingestion by odontocetes from the Western South Atlantic. Between 2018 and 2022, 154 stomachs from six species were collected from stranded individuals and incidental captures. Stomach contents were analyzed with the naked eye and items of anthropic origin found were counted and physically/chemically characterized. Generalized Linear Models were used to evaluate the influence of biological factors on the presence/absence of litter in stomachs, and for Pontoporia blainvillei only, the influence of these factors on the number of ingested items was also tested; additionally, a temporal analysis of ingestion was done for this species (1994–2022). A total of 156 items, mainly macro-sized plastics made of polypropylene, were found in 52 stomachs of four species: Tursiops spp. (FO% = 3.3%), Steno bredanensis (10.0%), Delphinus delphis (28.6%) and P. blainvillei (47.5%). The presence/absence of litter was explained only by species (χ2 = 28.29 and p < 0.001). For P. blainvillei, a threatened species in the region, the number of items was positively influenced by individual size (χ2 = 6.01 and p = 0.01) and sex (χ2 = 7.93 and p = 0.005). There was an increase in plastic ingestion by this species over the years (χ2 = 121.6 and p < 0.001) and it was estimated that 75% of P. blainvillei stomachs will contain plastic by 2040. The ingestion of litter by odontocetes from the Western South Atlantic was confirmed and the potential risks posed by this type of pollution were evidenced, especially since these species also face other anthropic pressures. These results further demonstrate the increasing threat of litter in the ocean and highlight the importance of circularity of plastics and proper waste management.

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• Changes in microbial community structure of bio-fouled polyolefins over a year-long seawater incubation in Hawai’i

  July 2024, article in peer-reviewed journal
  Environmental Microbiology Reports

  Elizabeth Connors, Laurent Lebreton, Jeff S. Bowman and Sarah-Jeanne Royer

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  • Publication journal: Environmental Microbiology Reports
  • Publication type: Article in peer-reviewed journal
  • Collaborators: Scripps Institution of Oceanography, California USA | Center for Marine Debris Research, Hawaii Pacific University, Hawaii, USA | The Ocean Cleanup Foundation, The Netherlands
  • Publication date: July 29, 2024
  • DOI: /10.1111/1758-2229.13283

  Abstract

  Plastic waste, especially positively buoyant polymers known as polyolefins, are a major component of floating debris in the marine environment. While plastic colonisation by marine microbes is well documented from environmental samples, the succession of marine microbial community structure over longer time scales (> > 1 month) and across different types and shapes of plastic debris is less certain. We analysed 16S rRNA and 18S rRNA amplicon gene sequences from biofilms on polyolefin debris floating in a flow-through seawater tank in Hawai’i to assess differences in microbial succession across the plastic types of polypropylene (PP) and both high-density polyethylene (HDPE) and low-density polyethylene (LDPE) made of different plastic shapes (rod, film and cube) under the same environmental conditions for 1 year. Regardless of type or shape, all plastic debris were dominated by the eukaryotic diatom Nitzschia, and only plastic type was significantly important for bacterial community structure over time (p = 0.005). PE plastics had higher differential abundance when compared to PP for 20 bacterial and eight eukaryotic taxa, including the known plastic degrading bacterial taxon Hyphomonas (p = 0.01). Results from our study provide empirical evidence that plastic type may be more important for bacterial than eukaryotic microbial community succession on polyolefin pollution under similar conditions.

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• Hydrothermal liquefaction of plastic marine debris from the North Pacific Garbage Patch

  July 2024, article in peer-reviewed journal
  Resources, Conservation & Recycling

  Juliano Souza dos Passos, Chantal Lorentz, Dorothée Laurenti, Sarah-Jeanne Royer, Ioannis Chontzoglou and Patrick Biller

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  • Publication journal: Resources, Conservation & Recycling
  • Publication type: Article in peer-reviewed journal
  • Collaborators: Department of Biological and Chemical Engineering, Aarhus University, Denmark | IRCELYON, Université Claude Bernard Lyon, France | The Ocean Cleanup, The Netherlands
  • Publication date: July 24, 2024
  • DOI: /10.1016/j.resconrec.2024.107822

  Abstract

  Ocean plastic waste poses a growing environmental threat, efforts are now underway to help clean the ocean surface or to prevent plastic streams entering. Repurposing these highly mixed polymers presents a great challenge due to their inherent complexity, intertanglement, and the presence of contaminants. Herein, we process real samples of ocean-floating plastics from the North Pacific Garbage Patch through supercritical hydrothermal liquefaction (HTL), targeting their chemical recycling into synthetic crude oil. Investigating key process parameters (temperature, pressure, time, and plastic load), we found that plastic load and temperature are crucial parameters influencing oil yield and that moderate conditions maximized hydrocarbon yield, reaching 90 wt%. Overall, longer residence times and higher temperatures favored aromatic-rich oils. We suggest a reaction pathway to account for hydrogen release from aromatization reactions, influencing paraffin, olefin, and aromatic contents. Supercritical HTL offers an effective, tailored approach for recycling complex plastic mixtures to produce synthetic crude oil.

  • Chemical recycling, Hydrothermal liquefaction, Plastic pollution, Polyolefins, Waste valorisation

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• Impact of microplastic pollution on breaking waves

  July 2024, article in peer-reviewed journal
  Physics of Fluids

  Jotam Bergfreund, Ciatta Wobill, Frederic M. Evers, Benjamin Hohermuth, Pascal Bertsch, Laurent Lebreton, Erich J. Windhab and Peter Fischer

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  • Publication journal: Physics of Fluids
  • Publication type: Article in peer-reviewed journal
  • Collaborators: Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland | Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland | The Ocean Cleanup, Rotterdam, The Netherlands and The Modelling House, Raglan, New Zealand
  • Publication date: July 16, 2024
  • DOI: /10.1063/5.0208507

  Abstract

  Anthropogenic plastic waste heavily pollutes global water systems. In particular, micron-sized plastic debris can have severe repercussions for the ocean flora and fauna. Microplastics may also affect physical processes such as wave breaking, which are critical for air–sea interaction and albedo. Nevertheless, the effects of micron-sized plastic debris on geophysical processes are widely unexplored. Herein, we investigate the effect of microplastic collected from the North Pacific and a surfactant mimicking surface active materials present in the ocean on the stability of foam generated by breaking wave experiments. We found that microplastic particles increase foam stability. In particular, an increased foam height was found in a column foaming setup, while an increased foam area was observed in a laboratory-scale breaking wave channel. We propose that microplastic particles assemble at the air–water interface of foam bubbles, form aggregates, presumably decrease the liquid drainage in the liquid film, and thus change the lifetime of the liquid film and the bubble. The effect of surfactants is generally larger due to their higher surface activity but still in a range where synergistic effects can be observed. Our results suggest that microplastic could influence oceanic processes essential for air–sea interaction, sea spray formation, and albedo.

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• A Laboratory Study of the Effects of Size, Density, and Shape on the Wave-Induced Transport of Floating Marine Litter

  July 2024, article in peer-reviewed journal
  Advancing Earth and Space Sciences

  R. Calvert, A. Peytavin, Y. Pham, A. Duhamel, J. van der Zanden, S. M. van Essen, B. Sainte-Rose and T. S. van den Bremer

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Advancing Earth and Space Sciences
  • Publication date: July 11, 2024
  • Collaborators: School of Engineering, University of Edinburgh, Edinburgh, United Kingdom | Faculty of Civil Engineering and Geosciences, Delft University of Technology, The Netherlands | The Ocean Cleanup Foundation, The Netherlands | Maritime Research Institute Netherlands, Wageningen, The Netherlands, | Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, The Netherlands | Department of Engineering Science, University of Oxford, United Kingdom
  • DOI: /10.1029/2023JC020661

  Abstract

  Floating marine litter is transported by several mechanisms, including surface waves. In studies of marine litter transport, the wave-induced drift is set to be equal to the Stokes drift, corresponding to the Lagrangian-mean wave-induced drift of an infinitesimally small tracer. Large-scale experiments are used to show how the wave-induced drift of objects of finite size depends on their size, density, and shape. We observe increases in drift of 95% compared to Stokes drift for discs with diameters of 13% of the wavelength, up to 23% for spheres with diameters of 3% of the wavelength, whereas drift is reduced for objects that become submerged such as nets. We investigate what these findings may imply for the transport of plastic pollution in realistic wave conditions and we predict an increase in wave-induced drift for (very) large plastic pollution objects. The different extrapolation techniques we explore to make this prediction exhibit a large range of uncertainty.

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• Computer vision segmentation model—deep learning for categorizing microplastic debris

  July 2024, article in peer-reviewed journal
  Frontiers in Environmental Science

  Sarah-Jeanne Royer, Helen Wolter, Astrid E. Delorme, Laurent Lebreton and Olivier B. Poirion

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Frontiers in Environmental Science
  • Publication date: July 04, 2024
  • DOI: /10.3389/fenvs.2024.1386292
  • Collaborators: The Ocean Cleanup, Netherlands | Ifremer, Marine Structures Laboratory, Centre de Brest, France | Center for Marine Debris Research, Hawai’i Pacific University, Waimānalo, HI, United States | The Modelling House, Raglan, New Zealand | The Jackson Laboratory, United States

  Abstract

  The characterization of beached and marine microplastic debris is critical to understanding how plastic litter accumulates across the world’s oceans and identifying hotspots that should be targeted for early cleanup efforts. Currently, the most common monitoring method to quantify microplastics at sea requires physical sampling using surface trawling and sifting for beached microplastics, which are then followed by manual counting and laboratory analysis. The need for manual counting is time-consuming, operator-dependent, and incurs high costs, thereby preventing scalable deployment of consistent marine plastic monitoring worldwide. Here, we describe a workflow combining a simple experimental setup with advanced image processing techniques to conduct both quantitative and qualitative assessments of microplastic (0.05 cm

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• Densities of neuston often not elevated within plastic hotspots territory inside the North Pacific Garbage Patch

  July 2024, article in peer-reviewed journal
  Environmental Research Ecology

  Matthias Egger, Marjolein van Vulpen, Kiri Spanowicz, Kyle Wada, Yannick Pham, Helen Wolter, Samuel Fuhrimann and Laurent Lebreton

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Environmental Research Ecology
  • Publication date: July 11, 2024
  • DOI: 10.1088/2752-664X/ad4f92

  Abstract

  The North Pacific Garbage Patch, located in the eastern part of the North Pacific subtropical gyre, contains vast amounts of floating plastic debris. Research over the past decades has mainly focused on assessing the extent of plastic pollution in this oceanic region. However, the North Pacific subtropical gyre is also home to the surface-associated pelagic community known as neuston. To date, the dynamics of this ecosystem and its vulnerability towards environmental pollution and anthropogenic impacts remain poorly understood. While removing plastic debris afloat at sea can reduce negative impacts of plastic pollution on neuston and marine life in general, concerns have been raised that cleanup efforts could have an adverse effect on neuston due to potential co-accumulation of neuston and plastic at the sea surface. Here, we provide the most comprehensive assessment of neuston abundance in the eastern North Pacific Ocean and its relation to the distribution of floating plastic debris (0.05–5 cm in size) based on a first year-round survey. Our results reveal that neuston taxa inside the North Pacific Garbage Patch often show similar or lower abundances in areas with particularly high densities of floating plastic debris compared to the wider garbage patch. Targeting open-ocean cleanups on such plastic hotspot territories inside the garbage patch can therefore minimize interactions with neuston during cleanups, thus maximizing their net environmental gain. We further discover that neuston depicts substantial seasonal variability, which needs to be considered when assessing impacts on neuston.

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• Proof of concept for a new sensor to monitor marine litter from space

  June 2024, article in peer-reviewed journal
  Nature Communications

  Andrés Cózar, Manuel Arias, Giuseppe Suaria, Josué Viejo, Stefano Aliani, Aristeidis Koutroulis, James Delaney, Guillaume Bonnery, Diego Macías, Robin de Vries, Romain Sumerot, Carmen Morales-Caselles, Antonio Turiel, Daniel González-Fernández and Paolo Corradi

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Nature Communications
  • Publication date: June 14, 2024
  • Collaborators: Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz and European University of the Seas (SEA-EU), Puerto Real, Spain | Institute of Marine Sciences (ICM-CSIC), Barcelona Expert Center, Barcelona, Spain. | ARGANS France, Sophia-Antipolis, cedex, France | Universitat Politècnica de Catalunya (UPC), Barcelona, Spain | Istituto di Scienze Marine - Consiglio Nazionale delle Ricerche (ISMAR-CNR), Lerici, La Spezia, Italy | Technical University of Crete, School of Chemical and Environmental Engineering, Chania, Greece | ARGANS Ltd., Plymouth, United Kingdom | Airbus Defence and Space, Toulouse, France | European Commission, Joint Research Centre, Ispra, Italy | The Ocean Cleanup, Rotterdam, The Netherlands. | ACRI-ST, Sophia-Antipolis, France | European Space Agency - ESTEC, Noordwijk, The Netherlands.
  • DOI: 10.1038/s41467-024-48674-7

  Abstract

  Worldwide, governments are implementing strategies to combat marine litter. However, their effectiveness is largely unknown because we lack tools to systematically monitor marine litter over broad spatio-temporal scales. Metre-sized aggregations of floating debris generated by sea-surface convergence lines have been reported as a reliable target for detection from satellites. Yet, the usefulness of such ephemeral, scattered aggregations as proxy for sustained, large-scale monitoring of marine litter remains an open question for a dedicated Earth-Observation mission. Here, we track this proxy over a series of 300,000 satellite images of the entire Mediterranean Sea. The proxy is mainly related to recent inputs from land-based litter sources. Despite the limitations of in-orbit technology, satellite detections are sufficient to map hot-spots and capture trends, providing an unprecedented source-to-sink view of the marine litter phenomenon. Torrential rains largely control marine litter inputs, while coastal boundary currents and wind-driven surface sweep arise as key drivers for its distribution over the ocean. Satellite-based monitoring proves to be a real game changer for marine litter research and management. Furthermore, the development of an ad-hoc sensor can lower the minimum detectable concentration by one order of magnitude, ensuring operational monitoring, at least for seasonal-to-interannual variability in the mesoscale.

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• Biodegradation of polyethylene by the marine fungus Parengyodontium album

  April 2024, article in peer-reviewed journal
  Science of The Total Environment

  A. Vaksmaa, H. Vielfaure, L. Polerecky, M.V.M. Kienhuis, M.T.J. van der Meer, T. Pflüger, M. Egger and H. Niemann

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Science of The Total Environment
  • Collaborators: NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, the Netherlands | Université de Paris, INSERM U1284, Center for Research and Interdisciplinarity (CRI), France | Department of Earth Sciences, Faculty of Geosciences, Utrecht University, the Netherlands | Department of Plant and Environmental Sciences, University of Copenhagen, Denmark | The Ocean Cleanup, the Netherlands | Egger Research and Consulting, Switzerland
  • Available online: April 26, 2024
  • DOI: 10.1016/j.scitotenv.2024.172819

  Abstract

  Plastic pollution in the marine realm is a severe environmental problem. Nevertheless, plastic may also serve as a potential carbon and energy source for microbes, yet the contribution of marine microbes, especially marine fungi to plastic degradation is not well constrained. We isolated the fungus Parengyodontium album from floating plastic debris in the North Pacific Subtropical Gyre and measured fungal-mediated mineralization rates (conversion to CO2) of polyethylene (PE) by applying stable isotope probing assays with 13C-PE over 9 days of incubation. When the PE was pretreated with UV light, the biodegradation rate of the initially added PE was 0.044 %/day. Furthermore, we traced the incorporation of PE-derived 13C carbon into P. album biomass using nanoSIMS and fatty acid analysis. Despite the high mineralization rate of the UV-treated 13C-PE, incorporation of PE-derived 13C into fungal cells was minor, and 13C incorporation was not detectable for the non-treated PE. Together, our results reveal the potential of P. album to degrade PE in the marine environment and to mineralize it to CO2. However, the initial photodegradation of PE is crucial for P. album to metabolize the PE-derived carbon.

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• Simulating drifting fish aggregating device trajectories to identify potential interactions with endangered sea turtles

  May 2024, article in peer-reviewed journal
  Conservation Biology

  Lauriane Escalle, J. Scutt Phillips, J. Lopez, J. M. Lynch, H. Murua, S. J. Royer, Y. Swimmer, J. Murua, Alex Sen Gupta, V. Restrepo and G. Moreno

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Conservation Biology
  • Collaborators: Oceanic Fisheries Programme, The Pacific Community (SPC), Nouméa, New Caledonia | Ecosystem and Bycatch Program, Inter-American Tropical Tuna Commission (IATTC), La Jolla, California, USA | Center for Marine Debris Research (CMDR), Hawaii Pacific University (HPU), Waimanalo, Hawaii, USA | Chemical Sciences Division, National Institute of Standards and Technology (NIST), Waimanalo, Hawaii, USA | 5International Seafood Sustainability Foundation (ISSF), Pittsburgh, Pennsylvania, USA | The Ocean Cleanup, Rotterdam, The Netherlands | NOAA Fisheries, Pacific Islands Fisheries Science Center, Honolulu, Hawaii, USA | AZTI Tecnalia, Sukarrieta, Spain | Climate Change Research Centre and ARC Centre of Excellence for Climate Extremes, University of New South Wales, Sydney, Australia
  • Publication date: 20 May 2024
  • DOI: 10.1111/cobi.14295

  Abstract

  Purse-seine fishers using drifting fish aggregating devices (dFADs), mainly built with bamboo, plastic buoys, and plastic netting, to aggregate and catch tropical tuna, deploy 46,000–65,000 dFADs per year in the Pacific Ocean. Some of the major concerns associated with this widespread fishing device are potential entanglement of sea turtles and other marine fauna in dFAD netting; marine debris and pollution; and potential ecological damage via stranding on coral reefs, beaches, and other essential habitats for marine fauna. To assess and quantify the potential connectivity (number of dFADs deployed in an area and arriving in another area) between dFAD deployment areas and important oceanic or coastal habitat of critically endangered leatherback (Dermochelys coriacea) and hawksbill (Eretmochelys imbricata) sea turtles in the Pacific Ocean, we conducted passive-drift Lagrangian experiments with simulated dFAD drift profiles and compared them with known important sea turtle areas. Up to 60% of dFADs from equatorial areas were arriving in essential sea turtle habitats. Connectivity was less when only areas where dFADs are currently deployed were used. Our simulations identified potential regions of dFAD interactions with migration and feeding habitats of the east Pacific leatherback turtle in the tropical southeastern Pacific Ocean; coastal habitats of leatherback and hawksbill in the western Pacific (e.g., archipelagic zones of Indonesia, Papua New Guinea, and Solomon Islands); and foraging habitat of leatherback in a large equatorial area south of Hawaii. Additional research is needed to estimate entanglements of sea turtles with dFADs at sea and to quantify the likely changes in connectivity and distribution of dFADs under new management measures, such as use of alternative nonentangling dFAD designs that biodegrade, or changes in deployment strategies, such as shifting locations.

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• Anthropogenic Debris in Three Sympatric Seal Species of The Western Antarctic Peninsula

  February 2024, article in a peer-reviewed journal
  Science of The Total Environment

  Julieta D. Cebuhar, Javier Negrete, Lucas S. Rodríguez Pirani, A. Lorena Picone, Maira Proietti, Rosana M. Romano, Carlos O. Della Védova, Ricardo Casaux, Eduardo R. Secchi and Silvina Botta

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Science of The Total Environment
  • Publication date: February 24, 2024
  • Collaborators: Laboratório de Ecologia e Conservação da Megafauna Mari, Instituto de Oceanografia, Universidade Federal do Rio Grande-FURG (BR), Programa de Pós-Graduação em Oceanografia Biológica, Instituto de Oceanografia, Universidade Federal do Rio Grande-FURG (BR), Laboratório de Predadores Tope, Instituto Antártico Argentino (ARG), Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata (ARG), Consejo Nacional de Investigaciones Científicas Y Técnicas (CONICET)(ARG), CEQUINOR (UNLP, CCT-CONICET La Plata, associated with CIC), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (ARG), Laboratório de Ecologia Molecular Marinha and Projeto Lixo Marinho, Instituto de Oceanografia, Universidade Federal do Rio Grande-FURG (BR), The Ocean Cleanup (NL), Centro de Investigación Esquel de Montaña y Estepa Patagónica (CIEMEP) (ARG)
  • DOI: 10.1016/j.scitotenv.2024.171273

  Abstract

  Litter pollution is a growing concern, including for Antarctica and the species that inhabit this ecosystem. In this study, we investigated the microplastic contamination in three seal species that inhabit the Western Antarctic Peninsula: crabeater (Lobodon carcinophaga), leopard (Hydrurga leptonyx) and Weddell (Leptonychotes weddellii) seals. Given the worldwide ubiquity of this type of contaminant, including the Southern Ocean, we hypothesized that the three seal species would present anthropogenic debris in their feces. We examined 29 scat samples of crabeater (n = 5), leopard (n = 13) and Weddell (n = 11) seals. The chemical composition of the items found were identified using micro-Raman and micro-FTIR spectroscopies. All the samples of the three species presented anthropic particles (frequency of occurrence – %FO – 100 %). Fibers were the predominant debris, but fragments and filaments were also present. Particles smaller than 5 mm (micro debris) were predominant in all the samples. Leopard seals ingested significantly larger micro-debris in comparison with the other seal species. The dominant color was black followed by blue and white. Micro-Raman and micro-FTIR Spectroscopies revealed the presence of different anthropogenic pigments such as reactive blue 238, Indigo 3600 and copper phthalocyanine (blue and green). Carbon black was also detected in the samples, as well as plastic polymers such as polystyrene, polyester and polyethylene terephthalate (PET), polyamide, polypropylene and polyurethane These results confirm the presence of anthropogenic contamination in Antarctic seals and highlight the need for actions to mitigate the effects and reduce the contribution of debris in the Antarctic ecosystem.

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• Wind- and rain-driven macroplastic mobilization and transport on land

  February 2024, article in a peer-reviewed journal
  Scientific Reports

  Yvette A. M. Mellink, Tim H. M. van Emmerik and Thomas Mani

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Scientific Reports
  • Publication date: February 16, 2024
  • Collaborators: Hydrology and Environmental Hydraulics Group, Wageningen University and Research (NL), The Ocean Cleanup (NL)
  • DOI: 10.1038/s41598-024-53971-8

  Abstract

  Wind and rain are considered main drivers for mobilization and transport of macroplastics on land, yet there is a lack of empirical data that quantifies this. We present lab experiment results on land-based macroplastic mobilization and transport. We placed four types of macroplastics on terrains with varying surface roughness and slope angles, and exposed them to changing wind speeds and rain intensities. In general, we find that the mobilization probability and transport velocity of macroplastics strongly depend on the combination of the terrain characteristics and material properties. At Beaufort 3, 100% of the plastic bags were mobilized, whereas for the other plastic types less than 50% were mobilized. We found 1.4 (grass) to 5 times (paved surface) higher mobilization probabilities on land than assumed by existing plastic transport models. Macroplastic transport velocities were positively correlated with wind speed, but not with rain intensity. This suggests that macroplastics are not transported on land by rain unless surface runoff develops that can bring the macroplastics afloat. Macroplastic transport velocities were, driven by wind, 1.9 and, driven by rain, 4.9 times faster on paved surfaces than on grass. This study enhances our understanding of land-based macroplastic transport and provides an empirical basis for models.

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• Hyperspectral reflectance of pristine, ocean weathered and biofouled plastics from a dry to wet and submerged state

  December 2023, article in a peer-reviewed journal
  Earth Systems Science Data

  Robin V.F. de Vries, Shungudzemwoyo P. Garaba and Sarah-Jeanne Royer

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  • Publication type: article in a peer-reviewed journal
  • Publication journal: Earth System Science Data
  • Publication date: 08 December 2023
  • Collaborators: Wilhelmshaven tank construction by Gerrit Behrens, Helmo Nicolai, and Waldemar Siewert (NL), Timo Sanders, Steon Engineering Plastics (NL), Hawai'i Pacific University and the Center for Marine Debris Research (USA), Paolo Corradi of the European Space Agency (FR), Discovery Element of the European Space Agency's Basic Activities (FR), The Ocean Cleanup (NL)
  • DOI: /10.5194/essd-15-5575-2023

  Abstract

  High-quality spectral reference libraries are important for algorithm development and identification of diagnostic optical characteristics of target objects in earth observation monitoring applications. We present additional measurements conducted using hyperspectral sensor technologies in a laboratory and an outdoor setting to further extend high-quality data as well as diversity in available open-access spectral reference libraries. These observations involved gathering hyperspectral single-pixel-point and multipixel optical properties of a diverse set of plastic materials (e.g., ropes, nets, packaging, and personal protective equipment). Measurements of COVID-19 personal protective equipment were conducted to also further expand spectral reference datasets that could be useful in remote sensing the mismanaged waste in the natural environment that was generated during the pandemic. The sample set consisted of virgin polymers and ocean weathered and artificially biofouled objects of varying apparent colors, shapes, forms, thicknesses, and opacity. A Spectral Evolution spectroradiometer was used to collect hyperspectral reflectance single-pixel-point information from 280 to 2500 nm. Imaging was also performed using a Specim IQ hyperspectral camera from 400 to 1000 nm. Sampling underwater was completed in intervals of 0.005–0.215 m within a depth range covering 0.005–0.715 m. All optical measurements are available in open access for the laboratory experiment via https://doi.org/10.4121/769cc482-b104-4927-a94b-b16f6618c3b3 (de Vries and Garaba, 2023) and an outdoor campaign involving the biofouling samples via https://doi.org/10.4121/7c53b72a-be97-478b-9288-ff9c850de64b (de Vries et al., 2023).

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• Legacy oceanic plastic pollution must be addressed to mitigate possible long-term ecological impacts

  November 2023, article in a peer-reviewed journal
  Microplastics and Nanoplastics

  Camille Richon, Karin Kvale, Laurent Lebreton and Matthias Egger

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Microplastics and Nanoplastics
  • Publication date: 13 November 2023
  • Collaborators: Laboratoire d’Océanographie et du Climat: Expérimentations et Approches Numériques, LOCEAN-IPSL, Sorbonne Université (FR), Laboratoire d’Océanographie Physique et Spatiale (LOPS), Université de Bretagne Occidentale (FR), GNS Science (NZ), The Ocean Cleanup (NL), The Modelling House (NZ), Egger Research and Consulting (CH)
  • DOI: /10.1186/s43591-023-00074-2

  Abstract

  Scientific research over the past decade has demonstrated that plastic in our oceans has detrimental consequences for marine life at all trophic levels. As countries negotiate an international legally binding instrument on plastic pollution, the focus is on eliminating plastic emissions to the environment. Here, we argue that, while this endeavour is urgently needed to limit the negative impacts of plastic on ocean ecosystems, the reduction of the plastic flow to the environment should not be the sole purpose of the negotiations. Legacy oceanic plastic pollution is also a major concern that needs to be addressed in the coming Treaty. Plastic is ubiquitous and persistent in the environment, and its slow degradation produces uncountable amounts of potentially even more impactful micro- and nanoparticles. Thus, plastic that is already present in the oceans may continue to affect ecosystems for centuries. Recent global assessments reveal that microplastics could have a significant impact on biogeochemical cycles and microbial food chains within ocean ecosystems that may be equivalent to those of climate change. Therefore, we argue that cleanup initiatives are essential to avoid further longterm impacts of legacy oceanic pollution. The upcoming international negotiations to develop a new Global Plastics Treaty should aim at urgently reducing the flow of plastic to the marine environment while supporting innovative solutions towards efficient monitoring and cleanup of the legacy oceanic plastic pollution.

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• Training the next generation of plastics pollution researchers: tools, skills and career perspectives in an interdisciplinary and transdisciplinary field

  November 2023, article in a peer-reviewed journal
  Microplastics and Nanoplastics

  Denise M. Mitrano, Moritz Bigalke, Andy M. Booth, Camilla Catarci Carteny, Scott Coffin, Matthias Egger, Andreas Gondikas, Thorsten Hüffer, Albert A. Koelmans, Elma Lahive, Karin Mattsson, Stephanie Reynaud and Stephan Wagner

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Microplastics and Nanoplastics
  • Publication date: November 2023
  • DOI: /10.1186/s43591-023-00072-4

  Abstract

  Plastics pollution research attracts scientists from diverse disciplines. Many Early Career Researchers (ECRs) are drawn to this field to investigate and subsequently mitigate the negative impacts of plastics. Solving the multi-faceted plastic problem will always require breakthroughs across all levels of science disciplinarity, which supports interdisciplinary discoveries and underpins transdisciplinary solutions. In this context, ECRs have the opportunity to work across scientific discipline boundaries and connect with different stakeholders, including industry, policymakers and the public. To fully realize their potential, ECRs need to develop strong communication and project management skills to be able to effectively interface with academic peers and non-academic stakeholders. At the end of their formal education, many ECRs will choose to leave academia and pursue a career in private industry, government, research institutes or non-governmental organizations (NGOs). Here we give perspectives on how ECRs can develop the skills to tackle the challenges and opportunities of this transdisciplinary research field and how these skills can be transferred to different working sectors. We also explore how advisors can support an ECRs’ growth through inclusive leadership and coaching. We further consider the roles each party may play in developing ECRs into mature scientists by helping them build a strong foundation, while also critically assessing problems in an interdisciplinary and transdisciplinary context. We hope these concepts can be useful in fostering the development of the next generation of plastics pollution researchers so they can address this global challenge more effectively.

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• On the Digital Twin of the Ocean Cleanup Systems—Part I: Calibration of the Drag Coefficients of a Netted Screen in OrcaFlex Using CFD and Full-Scale Experiments

  October 2023, article in a peer-reviewed journal
  Journal of Marine Science and Engineering

  Martin Alejandro Gonzalez Jimenez, Andriarimina Daniel Rakotonirina, Bruno Sainte-Rose and David James Cox

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Journal of Marine Science and Engineering
  • Publication date: October 2023
  • Collaborators: The Ocean Cleanup (NL)
  • DOI: /10.3390/jmse11101943

  Abstract

  The Ocean Cleanup introduces a Digital Twin (DT) describing the cleanup systems made of netting to extract marine litter from our oceans. It consists of two wings forming a “U-shape” and a retention zone. During operation, the system is towed and drag-driven with a span-to-length ratio of 0.6 ≤ 𝑆𝑅∗ ≤ 0.8. The twine Reynolds number is ℛ𝑒∗𝑡∈[800:1600], making it experience various local drag coefficients. The DT was built with OrcaFlex (OF) aiming at: (i) avoiding over- or under-designing the system; (ii) supporting the scale-up of the system; and (iii) estimating the costs and/or the impact of our offshore operations. Therefore, we present an attempt to build an accurate DT using data from the Great Pacific Garbage Patch (GPGP). We developed a three-cycle validation: (i) initial guess applying Naumov’s semi-empirical drag coefficient to define the OF drag coefficients without the influence of the angles of attack 𝜃 of the wings; (ii) adjustment of the OF drag coefficients using AquaSim (AS) with its twine-by-twine drag correlation for various 𝜃; (iii) re-adjustment of the OF drag coefficients from two-dimensional CFD simulations using Direct Numerical Simulation (DNS) for a twine-by-twine establishment of a drag correlation on a 1 m plane net, highlighting the shielding effects for 𝜃

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• Large floating abandoned, lost or discarded fishing gear (ALDFG) is frequent marine pollution in the Hawaiian Islands and Palmyra Atoll

  November 2023, article in a peer-reviewed journal
  Marine Pollution Bulletin

  Sarah-Jeanne Royer, Raquel N. Corniuk, Andrew McWhirter, Harry W. Lynch IV, Kydd Pollock, Kevin O'Brien, Lauriane Escalle, Katherine A. Stevens, Gala Moreno and Jennifer M. Lynch

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Marine Pollution Bulletin
  • Publication date: November 2023
  • Collaborators: Center for Marine Debris Research, Hawaiʻi Pacific University (USA), The Ocean Cleanup (NL), The Nature Conservancy (USA), Papahānaumokuākea Marine Debris Project (USA), Oceanic Fisheries Programme, The Pacific Community (NCL), International Seafood Sustainability Foundation (ISSF) (USA), Chemical Sciences Division, National Institute of Standards and Technology (USA)
  • DOI: /10.1016/j.marpolbul.2023.115585

  Abstract

  Abandoned, lost, or discarded fishing gear (ALDFG) is a major source of marine debris with significant ecological and economic consequences. We documented the frequency, types, sizes, and impacts of ALDFG recovered from Hawaiʻi and Palmyra Atoll in the Central North Pacific Ocean (CNPO) from 2009 to 2021. A total of 253 events weighing 15 metric tons were recovered, including 120 drifting fish aggregating device (dFAD) components, 61 conglomerates, fewer distinct nets, lines, buoys, and unique gear. The Hawaiian Islands were dominated by conglomerates and Palmyra Atoll by dFADs. DFADs were connected to the Eastern Pacific tropical tuna purse seine fishery. Windward O’ahu experienced up to seven events or 1800 kg of ALDFG per month. Across Hawaiʻ, ALDFG was present on 55 % of survey days, including hotspots with 100 % occurrence. Coral reef damage, entangled wildlife, navigational and removal costs are reported. The data highlight the large magnitude of ALDFG and associated impacts in the CNPO.

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• Do loggerhead sea turtle (Caretta caretta) gut contents reflect the types, colors and sources of plastic pollution in the Southwest Indian Ocean?

  September 2023, article in a peer-reviewed journal
  Marine Pollution Bulletin

  Margot Thibault, Ludovic Hoarau, Laurent Lebreton, Matthieu Le Corre, Mathieu Barret, Emmanuel Cordier, Stéphane Ciccione, Sarah-Jeanne Royer, Alexandra Ter Halle , Aina Ramanampamonjy, Claire Jean and Mayeul Dalleau

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Marine Pollution Bulletin
  • Publication date: September 2023
  • Collaborators: UMR ENTROPIE, University of Reunion Island, Reunion Island (FR), Centre d'Étude et Découverte de Tortues Marine (CEDTM), Reunion Island (FR), The Ocean Cleanup (NL), Kelonia, The Marine Turtle Observatory of Reunion Island, Reunion Island (FR), Osu-Réunion, University of Reunion Island, Reunion Island (FR), CNRS, Université Toulouse III, Laboratoire des Interactions Moléculaires et Réactivité Chimique et Photochimique (IMRCP) (FR), Association CETAMADA (MG)
  • DOI: /10.1016/j.marpolbul.2023.115343

  Abstract

  We analyzed plastic debris ingested by loggerheads from bycatch between 2007 and 2021 in the Southwest Indian Ocean (SWIO). We also analyzed plastic debris accumulated on beaches of the east coast of Madagascar as a proxy for ocean plastics to compare the characteristics of beached plastics and plastic ingested by turtles. We conducted a “brand audit” of the plastics to determine their country of origin. An oceanic circulation model was used to identify the most likely sources of plastics in the SWIO. In total, 202 of the 266 loggerheads analyzed had ingested plastics. Plastics categorized as “hard” and “white” were equally dominant in loggerheads and on beaches, suggesting no diet selectivity. Both the brand audit and circulation modeling demonstrated that Southeast Asia is the main source of plastic pollution in the region. This study demonstrates that loggerheads can be used as bioindicators of plastic pollution in the SWIO.

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• Extent and reproduction of coastal species on plastic debris in the North Pacific Subtropical Gyre

  April 2023, article in a peer-reviewed journal
  Nature Ecology & Evolution

  Linsey E. Haram, James T. Carlton, Luca Centurioni, Henry Choong, Brendan Cornwell, Mary Crowley, Matthias Egger, Jan Hafner, Verena Hormann, Laurent Lebreton, Nikolai Maximenko, Megan McCuller, Cathryn Murray, Jenny Par, Andrey Shcherbina, Cynthia Wright and Gregory M. Ruiz

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  • Publication journal: Nature Ecology & Evolution
  • Publication type: Article in peer-reviewed journal
  • Publication date: 17 April 2023
  • DOI: /10.1038/s41559-023-01997-y
  • Collaborators: Coastal & Ocean Studies Program, Williams College and Mystic Seaport Museum (US), Scripps Institution of Oceanography, University of California (US), Royal British Columbia Museum (CA), Hopkins Marine Station, Stanford University (US), Ocean Voyages Institute (US), The Ocean Cleanup (NL), International Pacific Research Center, School of Ocean & Earth Science & Technology, University of Hawaii (US), North Carolina Museum of Natural Sciences (US), Institute of Ocean Sciences, Fisheries & Oceans Canada (CA), Applied Physics Laboratory, University of Washington (US)

  Abstract

  We show that the high seas are colonized by a diverse array of coastal species, which survive and reproduce in the open ocean, contributing strongly to its floating community composition. Analysis of rafting plastic debris in the eastern North Pacific Subtropical Gyre revealed 37 coastal invertebrate taxa, largely of Western Pacific origin, exceeding pelagic taxa richness by threefold. Coastal taxa, including diverse taxonomic groups and life history traits, occurred on 70.5% of debris items. Most coastal taxa possessed either direct development or asexual reproduction, possibly facilitating long-term persistence on rafts. Our results suggest that the historical lack of available substrate limited the colonization of the open ocean by coastal species, rather than physiological or ecological constraints as previously assumed. It appears that coastal species persist now in the open ocean as a substantial component of a neopelagic community sustained by the vast and expanding sea of plastic debris.

  • Community ecology, Invasive species

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• Understanding the interactions between cephalopods and marine litter: a research evaluation with identification of gaps and future perspectives

  March 2023, article in peer-reviewed journal
  Marine Pollution Bulletin

  Tainah B.N. Freitas, Tatiana S. Leite, Bruna de Ramos and Maíra C. Proietti

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  • Publication journal: Science Direct
  • Publication type: Article in peer-reviewed journal
  • Publication date: 16 March 2023
  • DOI: /10.1016/j.marpolbul.2023.114814
  • Collaborators: Programa de Pós-graduação em Oceanografia Biológica and Projeto Lixo Marinho, Instituto de Oceanografia, Universidade Federal do Rio Grande (BR), Laboratório de Métodos de Estudos Subaquáticos e Cefalópodes, Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina (BR), Departamento de Oceanografia, Universidade Federal de Pernambuco (BR), The Ocean Cleanup (NL)

  Abstract

  Litter is known to negatively affect numerous marine organisms, but the extent of such impacts is not well known for several groups, including cephalopods. Considering the ecological, behavioral and economic importance of these animals, we reviewed the types of interactions between cephalopods and litter in the scientific literature, to evaluate impacts and knowledge gaps. We found 30 papers, which included records of microplastic ingestion and the transfer of synthetic microfibers along the food web. The largest number of records involved litter use as shelter, and the common octopus was the most frequent species. At first sight, litter use as shelter could appear to be a potential positive effect, but it is necessary to clarify the implications of this choice and its long-term consequences. Regarding ingestion and trophic transfer, further research is needed to elucidate its occurrence and impacts on cephalopods and their predators, including humans.

  • Cephalopod, Ingestion, Marine debris, Microplastics, Scientometric review, Shelter selection

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• Pelagic microplastics in the North Pacific subtropical gyre: a prevalent anthropogenic component of the particulate organic carbon pool

  March 2023, article in peer-reviewed journal
  PNAS Nexus

  Shiye Zhao, Tracy J Mincer, Laurent Lebreton and Matthias Egger

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  • Publication journal: PNAS Nexus
  • Publication type: Accepted manuscript
  • Publication date: 09 March 2023
  • DOI: 10.1093/pnasnexus/pgad070
  • Collaborators: Japan Agency for Marine-Earth Science and Technology (JP), Harbor Branch Oceanographic Institute, Florida Atlantic University (USA), Department of Biology, Wilkes Honors College, Florida Atlantic University (USA), The Ocean Cleanup (NL), The Modelling House (NZ), Egger Research and Consulting (CH)

  Abstract

  Due to its ever-increasing ocean inputs, fossil-based microplastics (MP) comprise a considerable constituent in the particulate organic carbon (POC) pool, which is instrumental in ocean biogeochemical cycling. Their distribution within the oceanic water column and the underpinning processes, however, remain unclear. Here we show that MP prevail throughout the water column of the eastern North Pacific subtropical gyre, comprising 334 #/m3 (84.5% of plastic particles <100 μm), with exponential relationships between concentrations and water depth in the upper 500-m layer and marked accumulation below this layer. Our results suggest that the biological carbon pump (BCP) strongly contributes to the water-column MP redistribution in terms of polymer type, material density and particle size, which in turn could influence the efficiency of organic matter export to the deep sea. We further show that 14C-depleted plastic particles predictably are an emerging non-neglectable perturbation to radiocarbon signatures in the deep ocean through depletion of the 14C/C ratio in the POC pool. Our data provide insight into vertical MP flux and highlight the potential role of MP in alternating the marine particulate pool and interactions with the BCP.

  • Biological carbon pump, Marine particulate pool, Microplastic, North Pacific Subtropical Gyre, Vertical distribution

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• Gaining new insights into macroplastic transport ‘hotlines’ and fine-scale retention-remobilisation using small floating high-resolution satellite drifters in the Chao Phraya River estuary of Bangkok

  January 2023, article in peer-reviewed journal
  Environmental Pollution

  Thomas Mani , Yotwadee Hawangchu, Pummarin Khamdahsag, Jenyuk Lohwacharin, Doungkamon Phihusut, Isara Arsiranant, Chalatip Junchompoo and Ratchanon Piemjaiswang

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Environmental Pollution
  • Collaborators: The Ocean Cleanup (NL), Aquatic Resources Research Institute, Chulalongkorn University (TH), Environmental Research Institute, Chulalongkorn University (TH), Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University (TH), Program Management Unit for Human Resources & Institutional Development, Research and Innovation (PMU-B), Office of National Higher Education Science Research and Innovation Policy Council, Ministry of Higher Education, Science, Research and Innovation (TH), Marine and Coastal Resources Research Center (TH)
  • Publication date: 19 January 2023
  • DOI: /10.1016/j.envpol.2023.121124

  Abstract

  In river plastic pollution research little is known about the detailed pathways and interruptions that occur during the journey of macroplastic debris (>5 cm) from land to sea. Data on fine-scale and high-accuracy transport trajectories and cycles of retention (when macroplastics are trapped, e.g. at a pier) and remobilisation is needed to inform global river plastic transport models as well as mechanical cleanup efforts. Though well established in the marine environment, the use of floating satellite drifters to understand macroplastic debris transport in tidal rivers and estuaries is in its infancy. Exploring the capacity to investigate fine-scale macroplastic debris-estuary interactions, this study brings together, on the one hand, a small, sensitive, floating satellite drifter with, on the other hand, the major riverine-marine habitat of the Chao Phraya River estuary at Bangkok, Thailand. The used grapefruit-sized drifters (n = 5) with minimal drogue (ρ ≈ 0.67 g/cm³) sent their positions at up to 4 m and 5 min spatiotemporal resolution via cellular GSM network for up to 48 days. This study indicates that river macroplastic debris transport ‘hotlines’ (positions where floating debris will likely pass by in a river) as well as retention-remobilisation cycles can be studied at fine scale. On their way through the river and gulf, covering between 9 and 696 km, drifters got stuck up to 23 times, spending 80% of their river lifetime in retention. Furthermore, it is outlined that the trajectories can be linked with environmental factors such as bathymetry and tides to more accurately model macroplastic debris behaviour in rivers. Finally, it is shown that trajectories crossing the riverine-marine continuum at the estuary can be accurately traced to support future investigations on the so far scarcely evidenced river mouth emissions of macroplastic debris.

  • GNSS and GPS, Hydrology and bathymetry, Macroplastic transport hotlines, Retention and remobilisation, River estuary, Surface drifters and trackers

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• Plastic Photodegradation Under Simulated Marine Conditions

  January 2023, Article in peer-reviewed journal
  Marine Pollution Bulletin

  Annalisa Delre, Maaike Goudriaan, Victor Hernando Morales, Annika Vaksmaa, Rachel Tintswalo Ndhlovu, Marianne Baas, Edwin Keijzer, Tim de Groot, Emna Zeghal, Matthias Egger, Thomas Rockmann and Helge Niemann

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Science Direct
  • Collaborators: NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology & Biogeochemistry (NL), University of Vigo, Biological Oceanography Group (ES), The Ocean Cleanup (NL), Egger Research and Consulting (CH), Utrecht University, Faculty of Science, Institute for Marine and Atmospheric Research (NL), Utrecht University, Faculty of Geosciences, Department of Earth Sciences (NL), University of Tromsø, CAGE - Centre for Arctic Gas Hydrate, Environment and Climate (NO)
  • DOI: 10.1016/j.marpolbul.2022.114544
  • Publication date: December 26, 2022

  Abstract

  Ocean plastic pollution is a problem of increasing magnitude; yet, the amount of plastic at the sea surface is much lower than expected. Solar ultraviolet (UV) radiation can induce photodegradation, but its importance in determining the longevity of foating plastic remains unconstrained. Here, we measured photodegradation rates of different plastic types slightly larger than microplastics (virgin polymers and foating plastic debris) under simulated marine conditions. UV irradiation caused all plastic types to leach dissolved organic carbon, and to a lesser degree carbon dioxide, carbon monoxide, methane, and other hydrocarbon gases. The release of photodegradation products translates to degradation rates of 1.7–2.3 % yr−1 of the tested plastic particles normalized to conditions as found in the subtropical surface ocean. Modelling the accumulation of foating plastic debris, our results show that solar UV radiation could already have degraded 7 to 22 % of all foating plastic that has ever been released to the sea.

  • Microplastic, Photodegradation, UV light

  • NIOZ summary post
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• Airborne Spectral Reflectance Dataset of Submerged Plastic Targets in a Coastal Environment

  January 2023, article in a peer-reviewed journal
  Data Journal

  Apostolos Papakonstantinou, Argyrios Moustakas, Polychronis Kolokoussis, Dimitris Papageorgiou, Robin de Vries and Konstantinos Topouzelis

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Data
  • Publication Date: 11 January 2023
  • Collaborators: Department of Marine Sciences, University of the Aegean, University Hill (GR), School of Rural, Surveying and Geoinformatics Engineering, National Technical University (GR), The Ocean Cleanup (NL)
  • DOI: 10.3390/data8010019

  Abstract

  Among the emerging applications of remote sensing technologies, the remote detection of plastic litter has observed successful applications in recent years. However, while the number of studies and datasets for spectral characterization of plastic is growing, few studies address plastic litter while being submerged in natural seawater in an outdoor context. This study aims to investigate the feasibility of hyperspectral characterization of submerged plastic litter in less-than-ideal conditions. We present a hyperspectral dataset of eight different polymers in field conditions, taken by an unmanned aerial vehicle (UAV) on different days in a three-week period. The measurements were carried out off the coast of Mytilene, Greece. The team collected the dataset using a Bayspec OCI-F push broom sensor from 25 m and 40 m height above the water. For a contextual background, the dataset also contains optical (RGB) high-resolution orthomosaics.

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• Persistency and Surface Convergence Evidenced by Two Maker Buoys in the Great Pacific Garbage Patch

  January 2023, Article in peer-reviewed journal
  Journal of Marine Science and Engineering

  Bruno Sainte-Rose, Yannick Pham and Wayne Pavalko

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Journal of Marine Science and Engineering
  • DOI: 10.3390/jmse11010068
  • Collaborators: The Ocean Cleanup (NL), WRG LLC (USA)
  • Publication date: 2 January 2023

  Abstract

  The accumulation of plastic debris on land and coastlines and in waterways and garbage patches is one of the greatest ecological concerns of the 21st century. In that context, the sources and pathways of plastic marine debris (PMD) have been increasingly studied in the past ten years. The purpose of this communication was to analyze, thanks to the tracks of two drifting buoys released in May–June 2019 in the North-East Pacific, two features encountered within the Great Pacific Garbage Patch (GPGP): a surface convergence, which could lead to the formation of plastic hotspots, and the persistency of the floating material in this area of the ocean. The evolution of the distance between the buoys was compared with the local circulation field divergence, a Lagrangian plastic dispersal model and sea-level anomalies (SLAs). These analyses highlighted the link between the converging behavior of the drifters and a persistent negative velocity divergence as well as a higher than average-encountered modelled plastic surface density (MPSD). The persistence of the material within the GPGP was observed thanks to the trajectory of the longest persisting drifter in comparison with the trajectory of the GPGP center and extent.

  • Circulation modeling, Drifters, Lagrangian particle tracking, Marine debris

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• The Status and Fate of Oceanic Garbage Patches

  November 2022, Comment article
  Nature Reviews, Earth and Environment

  Laurent Lebreton

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  • Publication type: Comment Article
  • Publication Journal: Nature Reviews Earth & Environment
  • Publication date: November 9, 2022
  • DOI: 10.1038/s43017-022-00363-z

  Abstract

  Floating plastic is accumulating in the five subtropical oceanic gyres, but little is known about their composition, sources, and fate. Monitoring has provided insight into persistence and accumulation processes in the North Pacific Ocean, but their relevance in other gyres is unknown. Identifying the sources of plastics, in all subtropical gyres, is necessary for cleanup efforts to be effective.

  • Great Pacific Garbage Patch, Plastic transport

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• Industrialised Fishing Nations Largely Contribute to Floating Plastic Pollution in the North Pacific Subtropical Gyre

  September 2022, Article in peer-reviewed journal
  Scientific Reports

  Laurent Lebreton, Sarah‑Jeanne Royer, Axel Peytavin, Wouter Jan Strietman, Ingeborg Smeding‑Zuurendonk and Matthias Egger

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Scientific Reports
  • Publication date: September 1, 2022
  • Collaborators: The Ocean Cleanup (NL), The Modelling House (NZ) Wageningen University & Research, Wageningen, The Netherlands, Egger Research and Consulting (CH)
  • DOI: s41598-022-16529-0

  Abstract

  The subtropical oceanic gyre in the North Pacific Ocean is currently covered with tens of thousands of tonnes of floating plastic debris, dispersed over millions of square kilometres. A large fraction is composed of fishing nets and ropes while the rest is mostly composed of hard plastic objects and fragments, sometimes carrying evidence on their origin. In 2019, an oceanographic mission conducted in the area, retrieved over 6000 hard plastic debris items> 5 cm. The debris was later sorted, counted, weighed, and analysed for evidence of origin and age. Our results, complemented with numerical model simulations and findings from a previous oceanographic mission, revealed that a majority of the floating material stems from fishing activities. While recent assessments for plastic inputs into the ocean point to coastal developing economies and rivers as major contributors into oceanic plastic pollution, here we shoshow that most floating plastics in the North Pacific subtropical gyre can be traced back to five industrialised fishing nations, highlighting the important role the fishing industry plays in the solution to this global issue.

  • Fishing Activity, Great Pacific Garbage Patch, Modeling, Ocean plastic pollution, Sampling

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• Pelagic distribution of plastic debris (> 500 µm) and marine organisms in the upper layer of the North Atlantic Ocean

  August 2022, article in peer-reviewed journal
  Scientific Reports

  Matthias Egger, Britte Schilt, Helen Wolter, Thomas Mani, Robin de Vries, Erik Zettler and Helge Niemann

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  • Publication type: Article in peer-reviewed article
  • Publication journal: Scientific Reports
  • Collaborators: The Ocean Cleanup (NL), Egger Research and Consulting (CH), Department of Earth Sciences–Geochemistry, Utrecht University (NL), NIOZ Royal Netherlands Institute for Sea Research (NL)
  • DOI: 10.1038/s41598-022-17742-7
  • Publication date: August 11, 2022

  Abstract

  At present, the distribution of plastic debris in the ocean water column remains largely unknown. Such information, however, is required to assess the exposure of marine organisms to plastic pollution as well as to calculate the ocean plastic mass balance. Here, we provide water column profiles (0–300 m water depth) of plastic (0.05–5 cm in size) concentration and key planktonic species from the eastern North Atlantic Ocean. The amount of plastic decreases rapidly in the upper few meters, from ~ 1 item/m3 (~ 1000 µg/m3) at the sea surface to values of ~ 0.001–0.01 items/m3 (~ 0.1–10 µg/m3) at 300 m depth. Ratios of plastic to plankton varied between ~ 10–5 and 1 plastic particles per individual with highest ratios typically found in the surface waters. We further observed that pelagic ratios were generally higher in the water column below the subtropical gyre compared to those in more coastal ecosystems. Lastly, we show plastic to (non-gelatinous) plankton ratios could be as high as ~ 102–107 plastic particles per individual when considering reported concentrations of small microplastics 

  • Environmental impact, Microplastics, North Atlantic Gyre

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• Microbial communities on plastic particles in surface waters differ from subsurface waters of the North Pacific Subtropical Gyre

  August 2022, Article in peer-reviewed journal
  Marine Pollution Bulletin

  Annika Vaksmaa, Matthias Egger, Claudia Lüke, Paula Dalcin Martins, RiccardoRosselli , Alejandro Abdala Asbuna and Helge Niemann

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Science Direct
  • Publication date: 3 August 2022
  • DOI: 10.1016/j.marpolbul.2022.113949
  • Collaborators: Department of Marine Microbiology & Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, 't Horntje, the Netherlands, The Ocean Cleanup (NL), Egger Research and Consulting (CH), Radboud University, Department of Microbiology (NL), Departamento de Fisiología, Genética y Microbiología, Facultad de Ciencias, Universidad de Alicante (ES), LABAQUA S.A.U, C/Dracma 16–18, Pol. Ind. (ES), Department of Earth Sciences, Faculty of Geosciences, Utrecht University (NL)

  Abstract

  The long-term fate of plastics in the ocean and their interactions with marine microorganisms remain poorly understood. In particular, the role of sinking plastic particles as a transport vector for surface microbes towards the deep sea has not been investigated. Here, we present the first data on the composition of microbial communities on floating and suspended plastic particles recovered from the surface to the bathypelagic water column (0-2000 m water depth) of the North Pacific Subtropical Gyre. Microbial community composition of suspended plastic particles differed from that of plastic particles afloat at the sea surface. However, in both compartments, a diversity of hydrocarbon-degrading bacteria was identified. These findings indicate that microbial community members initially present on floating plastics are quickly replaced by microorganisms acquired from deeper water layers, thus suggesting a limited efficiency of sinking plastic particles to vertically transport microorganisms in the North Pacific Subtropical Gyre.

  • Microbial communities, North Pacific Subtropical Gyre, Ocean plastic pollution

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• Size Dependent Transport of Floating Plastics Modeled in the Global Ocean

  July 2022, article in peer-reviewed journal
  Frontiers in Marine Science

  Doug Klink, Alex Peytavin and Laurent Lebreton

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Frontiers in Marine Science
  • Publication date: 20 July 2022
  • DOI: 10.3389/fmars.2022.903134
  • Collaborators: The Ocean Cleanup Foundation (NL), The Modelling House Limited (NZ)

  Abstract

  Plastic has been detected in the ocean in most locations where scientists have looked for it. While ubiquitous in the environment, plastic pollution is heterogeneous, and plastics of varying composition, shape, and size accumulate differently in the global ocean. Many physical and biological processes influence the transport of plastics in the marine environment. Here we focus on physical processes and how they can naturally sort floating plastics at the ocean surface and within its interior. We introduce a new open-source GPU-accelerated numerical model, ADVECT, which simulates the three-dimensional dispersal of large arrays of modelled ocean plastics with varying size, shape, and density. We use this model to run a global simulation and find that buoyant particles are sorted in the ocean according to their size, both at the surface due to wind-driven drift and in the water column due to their rising velocity. Finally, we compare our findings with recent literature reporting the size distribution of plastics in the ocean and discuss which observations can and cannot be explained by the physical processes encoded in our model.

  • Computational Model, GPU, Langarian transport

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• Plastics in Freshwater Bodies

  April 2022, Chapter in Scientific Book
  Plastics and the Ocean: Origin, Characterization, Fate, and Impacts

  Laurent Lebreton, Merel Kooi, Thomas Mani, Tim van Emmerik, Helen Wolter, Mine B. Tekman, Svenja M. Mintenig and Anthony L. Andrady

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  • Publication type: Chapter in Scientific Book
  • Chapter: 7
  • DOI: 10.1002/9781119768432.ch7
  • Publication date print: 20 April 2022
  • Publication date online: 27 May 2022

  Abstract

  Considering everything between macroplastics and nanoplastics, this chapter aims to provide a comprehensive and detailed assessment of the available methods to monitor and model plastics in freshwater bodies and to visualize the geographical distribution of studies reporting plastics in rivers and lakes. Both in marine or freshwater ecosystems, five steps can be distinguished for monitoring, namely, sampling, extraction, analysis, identification, and extrapolation. Despite the rapidly increasing number of publications on plastic occurrences in freshwater bodies, several aspects still carry high levels of uncertainty. The chapter highlights four key aspects that deserve more attention when designing and performing monitoring campaigns and when developing and interpreting numerical models. These four aspects are: temporal variation, transfer between environmental compartments, harmonization of monitoring and modeling investigations regarding plastic size ranges, and, finally, data quality control and validation of results.

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• Integrating Bayesian Belief Networks in a Toolbox for Decision Support on Plastic Clean-up Technologies in Rivers and Estuaries

  December 2021, Article in peer-reviewed journal
  Environmental Pollution

  Giulia Leone, Ana I. Catarinoa, Ine Pauwels, Thomas Mani, Michelle Tishler, Matthias Egger, Marie Anne Eurie Forio, Peter L.M. Goethals and Gert Everaert

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Environmental Pollution
  • Collaborators: Flanders Marine Institute (BE), Research Institute for Nature and Forest, Aquatic Management (BE), The Ocean Cleanup (NL), Egger Research and Consulting (CH), Ghent University, Research Group Aquatic Ecology (BE)
  • Publication date: 21 December 2021
  • DOI: 10.1016/j.envpol.2021.118721

  Abstract

  Current mitigation strategies to offset marine plastic pollution, a global concern, typically rely on preventing floating debris from reaching coastal ecosystems. Specifically, clean-up technologies are designed to collect plastics by removing debris from the aquatic environment such as rivers and estuaries. However, to date, there is little published data on their potential impact on riverine and estuarine organisms and ecosystems. Multiple parameters might play a role in the chances of biota and organic debris being unintentionally caught within a mechanical clean-up system, but their exact contribution to a potential impact is unknown. Here, we identified four clusters of parameters that can potentially determine the bycatch: (i) the environmental conditions in which the clean-up system is deployed, (ii) the traits of the biota the system interacts with, (iii) the traits of plastic items present in the system, and, (iv) the design and operation of the clean-up mechanism itself. To efficiently quantify and assess the influence of each of the clusters on bycatch, we suggest the use of transparent and objective tools. In particular, we discuss the use of Bayesian Belief Networks (BBNs) as a promising probabilistic modelling method for an evidence-based trade-off between removal efficiency and bycatch. We argue that BBN probabilistic models are a valuable tool to assist stakeholders, prior to the deployment of any clean-up technology, in selecting the best-suited mechanism to collect floating plastic debris while managing potential adverse effects on the ecosystem.

  • Bayesian Belief Networks, Decision support framework, Ecological modelling, Plastic waste mitigation technologies, Unintentional bycatch

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• Microplastics in the Weddell Sea (Antarctica): A Forensic Approach for Discrimination between Environmental and Vessel-Induced Microplastics

  November 2021, article in peer-reviewed journal
  Environmental Science and Technology

  Clara Leistenschneider, Patricia Burkhardt-Holm, Thomas Mani, Sebastian Primpke, Heidi Taubner and Gunnar Gerdts

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Environmental Science and Technology
  • DOI: 10.1021/acs.est.1c05207
  • Publication date: 28.11.2021

  Abstract

  Microplastic (MP) pollution has been found in the Southern Ocean surrounding Antarctica, but many local regions within this vast area remain uninvestigated. The remote Weddell Sea contributes to the global thermohaline circulation, and one of the two Antarctic gyres is located in that region. In the present study, we evaluate MP (>300 μm) concentration and composition in surface (n = 34) and subsurface water samples (n = 79, ∼11.2 m depth) of the Weddell Sea. All putative MP were analyzed by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. MP was found in 65% of surface and 11.4% of subsurface samples, with mean (±standard deviation (SD)) concentrations of 0.01 (±0.01 SD) MP m^–3 and 0.04 (±0.1 SD) MP m^–3, respectively, being within the range of previously reported values for regions south of the Polar Front. Additionally, we aimed to determine whether identified paint fragments (n = 394) derive from the research vessel. Environmentally sampled fragments (n = 101) with similar ATR-FTIR spectra to reference paints from the research vessel and fresh paint references generated in the laboratory were further subjected to micro-X-ray fluorescence spectroscopy (μXRF) to compare their elemental composition. This revealed that 45.5% of all recovered MP derived from vessel-induced contamination. However, 11% of the measured fragments could be distinguished from the reference paints via their elemental composition. This study demonstrates that differentiation based purely on visual characteristics and FTIR spectroscopy might not be sufficient for accurately determining sample contamination sources.

  • Antarctica, Microplastics, Vessels

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• Detecting the Great Pacific Garbage Patch floating plastic litter using WorldView-3 satellite imagery

  October 2021, article in a peer-reviewed journal
  Optics Express

  Young-Je Park, Shungudzemwoyo P. Garaba and Bruno Sainte-Rose

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  • Publication journal: Optics Express
  • Publication type: article in a peer-reviewed journal
  • Publication date: 13 October 2021
  • DOI: /10.1364/OE.440380

  Abstract

  We present a direct and proxy-based approach to qualitatively and semi-quantitatively observe floating plastic litter in the Great Pacific Garbage Patch (GPGP) based on a survey in 2018 using very high geo-spatial resolution 8-waveband WorldView-3 imagery. A proxy for the plastics was defined as a waveband difference for anomalies in the top-of-the-atmosphere spectra. The anomalies were computed by subtracting spatially varying reflectance of the surrounding ocean water as background from the top-of-the-atmosphere reflectance. Spectral shapes and magnitude were also evaluated using a reference target of known plastics, The Ocean Cleanup System 001 Wilson. Presence of ‘suspected plastics’ was confirmed by the similarity in derived anomalies and spectral shapes with respect to the known plastics in the image as well as direct observations in the true color composites. The proposed proxy-based approach is a step towards future mapping techniques of suspected floating plastics with potential operational monitoring applications from the Sentinel-2 that recently started regular imaging over the GPGP that will be supported or validated by numerical solutions and net trawling survey.

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• Quantifying Floating Plastic Debris at Sea Using Vessel-Based Optical Data and Artificial Intelligence

  August 2021, article in peer-reviewed journal
  Remote Sensing

  Robin de Vries, Matthias Egger, Thomas Mani and Laurent Lebreton

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Remote Sensing
  • Collaborators: The Ocean Cleanup (NL), Egger Research and Consulting (CH), The Modelling House (NZ)
  • DOI: 10.3390/rs13173401
  • Published at: 27 August 2021

  Abstract

  Despite recent advances in remote sensing of large accumulations of floating plastic debris, mainly in coastal regions, the quantification of individual macroplastic objects (>50 cm) remains challenging. Here, we have trained an object-detection algorithm by selecting and labeling footage of floating plastic debris recorded offshore with GPS-enabled action cameras aboard vessels of opportunity. Macroplastic numerical concentrations are estimated by combining the object detection solution with bulk processing of the optical data. Our results are consistent with macroplastic densities predicted by global plastic dispersal models, and reveal first insights into how camera recorded offshore macroplastic densities compare to micro- and mesoplastic concentrations collected with neuston trawls.

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• Microplastics and Anthropogenic Fibre Concentrations in Lakes Reflect Surrounding Land Use

  September 2021, Article in peer-reviewed journal
  PLOS Biology

  Andrew J. Tanentzap, Samuel Cottingham, Jérémy Fonvielle, Isobel Riley, Lucy M. Walker, Samuel G. Woodman, Danai Kontou, Christian M. Pichler, Erwin Reisner and Laurent Lebreton

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: PLOS Biology
  • Publication date: September 14, 2021
  • DOI: 10.1371/journal.pbio.3001389

  Abstract

  Pollution from microplastics and anthropogenic fibres threatens lakes, but we know little about what factors predict its accumulation. Lakes may be especially contaminated because of long water retention times and proximity to pollution sources. Here, we surveyed anthropogenic microparticles, i.e., microplastics and anthropogenic fibres, in surface waters of 67 European lakes spanning 30° of latitude and large environmental gradients. By collating data from >2,100 published net tows, we found that microparticle concentrations in our field survey were higher than previously reported in lakes and comparable to rivers and oceans. We then related microparticle concentrations in our field survey to surrounding land use, water chemistry, and plastic emissions to sites estimated from local hydrology, population density, and waste production. Microparticle concentrations in European lakes quadrupled as both estimated mismanaged waste inputs and wastewater treatment loads increased in catchments. Concentrations decreased by 2 and 5 times over the range of surrounding forest cover and potential in-lake biodegradation, respectively. As anthropogenic debris continues to pollute the environment, our data will help contextualise future work, and our models can inform control and remediation efforts.

  • lakes, Microplastics, Plastic pollution

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• Ocean Plastic Assimilator v0.2: assimilation of plastic concentration data into Lagrangian dispersion models

  July 2021, article in a peer-reviewed journal
  European Geosciences Union

  Axel Peytavin, Bruno Sainte-Rose, Gael Forget and Jean-Michel Campin

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  • Publication journal: European Geosciences Union
  • Publication type: Article in peer-reviewed journal
  • Publication date: 30 July 2021
  • DOI: /10.5194/gmd-14-4769-2021

  Abstract

  A numerical scheme to perform data assimilation of concentration measurements in Lagrangian models is presented, along with its first implementation called Ocean Plastic Assimilator, which aims to improve predictions of the distributions of plastics over the oceans. This scheme uses an ensemble method over a set of particle dispersion simulations. At each step, concentration observations are assimilated across the ensemble members by switching back and forth between Eulerian and Lagrangian representations. We design two experiments to assess the scheme efficacy and efficiency when assimilating simulated data in a simple double-gyre model. Analysis convergence is observed with higher accuracy when lowering observation variance or using a circulation model closer to the real circulation. Results show that the distribution of the mass of plastics in an area can effectively be improved with this simple assimilation scheme. Direct application to a real ocean dispersion model of the Great Pacific Garbage Patch is presented with simulated observations, which gives similarly encouraging results. Thus, this method is considered a suitable candidate for creating a tool to assimilate plastic concentration observations in real-world applications to estimate and forecast plastic distributions in the oceans. Finally, several improvements that could further enhance the method efficiency are identified.

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• An Inshore–Offshore Sorting System Revealed from Global Classification of Ocean Litter

  10 June 2021, Article in peer-reviewed journal
  Nature Sustainability

  Carmen Morales-Caselles, Josué Viejo, Elisa Martí, Daniel González-Fernández, Hannah Pragnell-Raasch, J. Ignacio González-Gordillo, Enrique Montero, Gonzalo M. Arroyo, Georg Hanke, Vanessa S. Salvo, Oihane C. Basurko, Nicholas Mallos, Laurent Lebreton, Fidel Echevarría, Tim van Emmerik, Carlos M. Duarte, José A. Gálvez, Erik van Sebille, François Galgani, Carlos M. García, Peter S. Ross, Ana Bartual, Christos Ioakeimidis, Gorka Markalain, Atsuhiko Isobe and Andrés Cózar

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Nature Sustainability
  • Publication date: 10 June 2021
  • DOI: 10.1038/s41893-021-00720-8

  Abstract

  The surge of research on marine litter is generating important information on its inputs, distribution and impacts, but data on the nature and origin of the litter remain scattered. Here, we harmonize worldwide litter-type inventories across seven major aquatic environments and find that a set of plastic items from take-out food and beverages largely dominates global litter, followed by those resulting from fishing activities. Compositional differences between environments point to a trend for litter to be trapped in nearshore areas so that land-sourced plastic is released to the open ocean, predominantly as small plastic fragments. The world differences in the composition of the nearshore litter sink reflected socioeconomic drivers, with a reduced relative weight of single-use items in high-income countries. Overall, this study helps inform urgently needed actions to manage the production, use and fate of the most polluting human-made items on our planet, but the challenge remains substantial.

  • Environmental impact, Sustainability

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• Relative Abundance of Floating Plastic Debris and Neuston in the Eastern North Pacific Ocean

  June 2021, Article in peer-reviewed journal
  Frontiers in Marine Science

  Matthias Egger, Lauren Quiros, Giulia Leone, Francesco Ferrari, Christiana M. Boeger and Michelle Tischler

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Frontiers in Marine Science
  • Publication date: 3 June 2021
  • Collaborators: The Ocean Cleanup (NL), Department of Earth Sciences, Utrecht University (NL), Flanders Marine Institute (BE), Naval Facilities Engineering Command Environmental Core, U.S. Navy, San Diego (US)
  • DOI: 10.3389/fmars.2021.626026

  Abstract

  Despite an increasing research conducted on ocean plastic pollution over the last decade, there are still large knowledge gaps in our current understanding of how floating plastic debris accumulating in subtropical oceanic gyres may harm the surface-associated pelagic community known as neuston. Removing floating plastic debris from the surface ocean can minimize potentially adverse effects of plastic pollution on the neuston, as well as prevent the formation of large quantities of secondary micro- and nanoplastics. However, due to the scarcity of observational data from remote and difficult to access offshore waters, neuston dynamics in subtropical oceanic gyres and thus the potential impacts of plastic pollution as well as of cleanup activities on the neuston remain uncertain. Here, we provide rare observational data of the relative distribution of floating plastic debris (0.05–5 cm in size) and members of the neuston in the eastern North Pacific Ocean. Our results reveal that the dominant neustonic species co-occurring with high concentrations of floating plastic debris in the North Pacific Garbage Patch (NPGP) such as Porpita porpita, Halobates spp., pteropods, isopods, heteropods, and crabs depict either a low atmospheric drag due to physical attributes or a potential plastic-associated fitness benefit such as increased surface area for oviposition and structure for habitat. We further observe relatively higher plastic to organism ratios inside the NPGP for most target species compared to waters outside the NPGP. The findings presented here provide a first observational baseline to develop ecological models that can help evaluate the long-term risks of plastic pollution and of offshore cleanup activities for neuston in the eastern North Pacific Ocean. We further suggest that offshore mitigation strategies aiming at removing floating plastic debris from the ocean surface need to evaluate both, the direct impact of neuston bycatch during plastic removal on neuston population dynamics, as well as the potential benefits of reducing the negative effects of plastic pollution on the neuston.

  • cleanup, environment, Great Pacific Garbage Patch, neston

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• More than 1000 rivers account for 80% of global riverine plastic emissions into the ocean

  April 2021, article in peer-reviewed journal
  Science Advances

  Lourens J.J. Meijer, Tim van Emmerik, Ruud van der Ent, Christian Schmidt and Laurent Lebreton

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Science Advances
  • Collaborators: The Ocean Cleanup (NL) Hydrology and Quantitative Water Management Group Wageningen University (NL), Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology (NL), Department of Physical Geography, Faculty of Geosciences, Utrecht University (NL), Department Aquatic Ecosystem Analysis, Helmholtz-Centre for Environmental Research - UFZ (DE), Department of Hydrogeology, Helmholtz-Centre for Environmental Research– UFZ (DE), The Modelling House (NZ)
  • Publication date: 04.30.21
  • DOI: doi/10.1126/sciadv.aaz5803.

  Abstract

  Plastic waste increasingly accumulates in the marine environment, but data on the distribution and quantification of riverine sources required for development of effective mitigation are limited. Our model approach includes geographically distributed data on plastic waste, land use, wind, precipitation, and rivers and calculates the probability for plastic waste to reach a river and subsequently the ocean. This probabilistic approach highlights regions that are likely to emit plastic into the ocean. We calibrated our model using recent field observations and show that emissions are distributed over more rivers than previously thought by up to two orders of magnitude. We estimate that more than 1000 rivers account for 80% of global annual emissions, which range between 0.8 million and 2.7 million metric tons per year, with small urban rivers among the most polluting. These high-resolution data allow for the focused development of mitigation strategies and technologies to reduce riverine plastic emissions

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• Coastal Garbage Patches: Fronts Accumulate Plastic Films at Ashmore Reef Marine Park (Pulau Pasir), Australia

  Article in peer-reviewed journal
  April 2021, Frontiers in Marine Science

  Sara Hajbane, Bruna Calmanovici, Julia Reisser, Adam Jolly, Vyvyan Summers, Francesco Ferrari, Anas Ghadouani and Charitha Pattiaratchi

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  • Publication journal: Frontiers in Marine Science
  • Publication type: Article in peer-reviewed journal
  • DOI: 10.3389/fmars.2021.613399
  • Collaborators: UWA Oceans Institute, The University of Western Australia (AUS), Oceans Graduate School, The University of Western Australia (AUS), Minderoo Foundation (AUS), The Ocean Cleanup (NL)
  • Publication date: 16.04.2021

  Abstract

  Millions of tons of buoyant plastic materials enter oceans annually, the majority originating from terrestrial sources and transported to oceans where oceanographic processes disperse or accumulate them. Some of these materials beach while others accumulate in convergent zones in coastal seas and the open ocean. Although accumulations associated with subtropical gyres, for example, the “Great Pacific Garbage Patch” (GPGP) are well-known, coastal accumulation zones have received less attention. Here we report quantities and characteristics of plastics accumulated in fronts encountered within the Ashmore Reef marine park (Pulau Pasir), northern Australia. These areas, as well as surrounding waters, were sampled using Manta trawls, drone, and snorkel surveys conducted in October 2018. With mean plastic concentrations of 523,146 pieces km² for plastics > 500 micron these hotpots contained plastic concentrations an order of magnitude higher than surrounding waters (16,561 pieces km²) and comparable to the largest known accumulation zone: the GPGP. Furthermore, the mean mass within hotspots was 5,161 g km² vs. 9 g km² in surrounding waters. Therefore, we classify the features described in this study as types of “Coastal Garbage Patches” (CGPs). Importantly, the coastal fronts accumulating plastics in CGPs are key habitats for many marine species. Biomass outnumbered plastics by weight, with a ratio of 0.521 in CGPs and 0.016 in surrounding waters vs. 287.7 recorded in the GPGP. Polymer types found between the CGPs and GPGP were similar, but plastic films vastly dominated in the CGPs, whilst they were amongst the rarest types found in the GPGP. This study demonstrates the existence of CGPs coinciding with high priority conservation zones in coastal waters and highlights a need for further research into these environments.

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• A Spatially Variable Scarcity of Floating Microplastics in the Eastern North Pacific Ocean

  Environmental research letter
  November 2020, IOP Science

  Matthias Egger, Rein Nijhof, Laurent Quiros, Giulia Leone, Sarah-Jeanne Royer, Andrew C McWhirter, Gennady A Kantakov, Vladimir I Radchenko, Evgeny A Pakhomov and Brian P V Hunt

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  • Publication type: Environmental research letter
  • Publication journal: IOP Science
  • DOI: 10.1088/1748-9326/abbb4f
  • Publication date: 05.11.2020
  • Contributors: The Ocean Cleanup Foundation (NL), Department of Earth Sciences, Utrecht University (NL), Scripps Institution of Oceanography (USA), Center for Marine Debris Research, Hawai’i Pacific University (USA), Far-Eastern Ecological Centre, Ltd. (RU), Pacific branch of VNIRO (TINRO) (RU), North Pacific Anadromous Fish Commission (CA), Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia (CA), Institute for the Oceans and Fisheries (IOF), University of British Columbia (CA) Hakai Institute, Heriot bay (CA), The Modelling House Limited (NZ)

  Abstract

  Plastic waste accumulating in the global ocean is an increasingly threatening environmental issue. To date, the floating and thus most visible fraction of ocean plastic pollution has been mapped at global scale. Yet, large knowledge gaps exist in our current understanding of the transport and transformation processes of positively buoyant plastic debris at the sea surface. Observations at sea typically report an apparent scarcity of microplastics (500 µm) and mesoplastics (0.5–5 cm) in the surface waters of the eastern North Pacific Ocean using data from 1136 040 plastic fragments collected by 679 neuston trawl deployments between 2015 and 2019. Our results reveal that the apparent microplastic scarcity is not uniformly distributed across the region. Instead, we show that the relative abundance of floating microplastics increases from the outside to the inside of the North Pacific Garbage Patch. We hypothesize that this observation could be explained by (i) a spatially variable microplastic removal due to spatial differences in ocean productivity, (ii) a differential dispersal of micro- vs. mesoplastics with a preferential accumulation of microplastics in the subtropical gyre, and/or (iii) the timescales associated with transport and fragmentation of plastic objects at the ocean surface with older, more degraded, floating plastic accumulation in subtropical gyres. The results presented here highlight that global estimates of the accumulation and removal of positively buoyant microplastics need to consider spatial aspects such as variations in ocean productivity, the dominant physical transport processes in a given area, as well as the time needed for a plastic object to reach the specific offshore location.

  • Great Pacific Garbage Patch, Microplastics

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• Concentration, Anisotropic and Apparent Colour Effects on Optical Reflectance Properties of Virgin and Ocean-harvested Plastics

  Article in peer-reviewed journal
  October 2020, Science Direct

  Shungudzemwoyo P.Garaba, Manuel Arias, Paolo Corradi, Tristan Harmel, Robin de Vries and Laurent Lebreton

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Science Direct
  • DOI: 10.1016/j.jhazmat.2020.124290
  • Collaborators: The Ocean Cleanup (NL), Marine Sensor Systems Group, Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg (DE), ARGANS Limited (FR), Optics Section, Mechatronics and Optics Division, European Space Research and Technology Centre (ESTEC), European Space Agency (NL), Géosciences Environnement Toulouse, UMR5563, Institut de Recherche pour le Développement/Centre National de la Recherche Scientifique /Université (FR), The Modelling House (NZ)
  • Publication date: 16.10.2020

  Abstract

  We present reflectance measurements collected from virgin and ocean-harvested plastics. Virgin plastics included high and low density polyethylene (HDPE, LDPE), polypropylene (PP) as well as polystyrene (PS). Ocean-harvested plastics were ropes, sheets, foam, pellets and fragmented items previously trawled from the North Pacific Garbage Patch. Nadir viewing angles and plastic pixel coverage were varied to advance our understanding of how reflectance shape and magnitude can be influenced by these parameters. We also investigated the effect of apparent colour of plastics on the measured reflectance from the ultraviolet (UV – 350 nm), visible, near to shortwave infrared (NIR, SWIR – 2500 nm). Statistical analyses indicated that the spectral reflectance of the plastics was significantly correlated to the percentage pixel coverage. There was no clear relationship between the reflectance observed and the viewing nadir angle but dampened materials seemed to be more isotropic (near-Lambertian) than their dry counterparts. A loss in reflectance was also determined between dry and wet plastics. Location of absorption features was not affected by the apparent colour of objects. In general, ocean-harvested plastics shared more identical absorption features (~960, 1215, 1440, 1732, 1920 nm) and had lower reflectance intensity compared to the virgin plastics (~980 nm). Prospects for satellite retrieval of plastic type and pixel plastic coverage are discussed based on Top-of-Atmosphere (TOA) signal simulated through radiative transfer computation using the documented plastic reflectances. Non-linear relationships between TOA reflectance and plastic coverage were observed depending on wavelength and plastic type. Most of the plastics analysed impact significantly the TOA signal but two plastic types did not produce strong signal at TOA (hard fragments, LDPE). Nevertheless, all plastic types produced detectable signals when observations were simulated within the sunglint direction. The measurements collected in this study are an extension to available high quality spectral reference libraries and can support further research in developing remote sensing algorithms for marine litter.

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• Manila River Mouths Act as Temporary Sinks for Macroplastic Pollution

  Article in peer-reviewed journal
  October 2020, Frontiers in Marine Science

  Tim van Emmerik, Justin van Klaveren, Lourens J. J. Meijer, Joost W. Krooshof, Dixie Ann A. Palmos and Maria Antonia Tanchuling

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Frontiers in Marine Science
  • DOI: 10.3389/fmars.2020.545812
  • Publication date: October 7, 2020
  • Contributors: Hydrology and Quantitative Water Management Group, Wageningen University, Wageningen, Netherlands The Ocean Cleanup, Rotterdam, Netherlands Science of Identity Foundation, Manila, Philippines Institute of Civil Engineering, University of the Philippines Diliman, Quezon City, Philippines

  Abstract

  The Philippines is suggested to be one of the world’s main contributors to global marine plastic pollution. Several rivers in the Manila metropolitan area are assumed to be main pathways of land-based plastic waste into the ocean. However, these model estimates remain uncertain due to a lack of field data. The main goal of this study was therefore to collect field data on floating macroplastic flux and polymer category in three of Manila’s main rivers: the Meycauayan, Tullahan and Pasig. We measured plastic flux, item polymer category, and flow velocity at two locations per river during an 11-day period. Each river was measured close to the river mouth, and several kilometer upstream. The results showed no significant difference between the plastic flux in upstream and downstream flow direction at the three river mouths. The Meycauayan and Pasig rivers did have significantly higher plastic flux at the river mouth compared to the upstream location. The observations suggest accumulation of macroplastics in the river mouths during periods of low freshwater discharge. In this case, instantaneous plastic flux is mainly determined by the tidal dynamics. It is hypothesized that plastics are temporarily retained in estuaries, and may be flushed out during neap tide or increased river discharge. Due to the retention capacity of the estuaries, net plastic export into the ocean could not be estimated. Future research is needed to further investigate the role of tidal dynamics on the transport and net export of riverine macroplastics.

  • Macroplastic, river pollution, Urban river

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• Automated River Plastic Monitoring Using Deep Learning and Cameras

  Article in peer-reviewed journal
  July 2020, Earth and Space Science

  Colin van Lieshout, Kees van Oeveren, Tim van Emmerik and Eric Postma

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  • Publication journal: Earth and Space Science
  • Publication type: Article in peer-reviewed journal
  • DOI: 10.1029/2019EA000960
  • Published on: July 28, 2020

  Abstract

  Quantifying plastic pollution on surface water is essential to understand and mitigate the impact of plastic pollution to the environment. Current monitoring methods such as visual counting are labor intensive. This limits the feasibility of scaling to long‐term monitoring at multiple locations. We present an automated method for monitoring plastic pollution that overcomes this limitation. Floating macroplastics are detected from images of the water surface using deep learning. We perform an experimental evaluation of our method using images from bridge‐mounted cameras at five different river locations across Jakarta, Indonesia. The four main results of the experimental evaluation are as follows. First, we realize a method that obtains a reliable estimate of plastic density (68.7% precision). Our monitoring method successfully distinguishes plastics from environmental elements, such as water surface reflection and organic waste. Second, when trained on one location, the method generalizes well to new locations with relatively similar conditions without retraining (≈50% average precision). Third, generalization to new locations with considerably different conditions can be boosted by retraining on only 50 objects of the new location (improving precision from ≈20% to ≈42%). Fourth, our method matches visual counting methods and detects ≈35% more plastics, even more so during periods of plastic transport rates of above 10 items per meter per minute. Taken together, these results demonstrate that our method is a promising way of monitoring plastic pollution. By extending the variety of the data set the monitoring method can be readily applied at a larger scale.

  • artificial intelligence, deep learning, Plastic pollution, river pollution

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• Transnational Plastics: An Australian Case for Global Action

  July 2020, policy brief article
  Frontiers in Environmental Science

  Ronen Galaiduk, Laurent Lebreton, Erika Techera and Julia Reisser

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  • Publication journal: Frontiers in Environmental Science
  • Publication type: Policy brief article
  • Collaborators: Australian Institute of Marine Science, Crawley, WA, Australia | The Modelling House, Raglan, New Zealand | The Ocean Cleanup Foundation, Delft, Netherlands | UWA Law School, The University of Western Australia, Perth, WA, Australia | UWA Oceans Institute, The University of Western Australia, Perth, WA, Australia
  • Publication date: July 22, 2020
  • DOI: /10.3389/fenvs.2020.00115

  Abstract

  Mitigating plastic pollution requires strong international cooperation because significant volumes of plastic waste are transported across jurisdictions both as waste exports and drifting ocean plastics (OP). Here we estimate which nations are (1) sources for overseas OP reaching Australian waters and (2) destinations receiving OP from Australian sources. We then provide actionable recommendations for mitigating plastic pollution in Australian waters and beyond. We estimated that the vast majority of overseas OP reaching Australia is from Indonesia, and that most of the Australian-sourced OP reaching overseas territories is entering New Zealand. Key actions for mitigating the OP issue in Australia include better governance, upgraded enforcement, and increased investments to reduce fossil fuel-based plastic production and to drastically improve both domestic and international waste management infrastructure and operations.

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• First evidence of plastic fallout from the North Pacific Garbage Patch

  Article in peer-reviewed journal
  May 2020, Journal of Hazardous Materials

  Matthias Egger, Fatimah Sulu-Gambari and Laurent Lebreton

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Scientific Reports
  • Collaborators: The Ocean Cleanup
  • Publication date: 06.05.2020
  • DOI: 10.1038/s41598-020-64465-8

  Abstract

  The infamous garbage patches on the surface of subtropical oceanic gyres are proof that plastic is polluting the ocean on an unprecedented scale. The fate of floating plastic debris ‘trapped’ in these gyres, however, remains largely unknown. Here, we provide the first evidence for the vertical transfer of plastic debris from the North Pacific Garbage Patch (NPGP) into the underlying deep sea. The numerical and mass concentrations of plastic fragments (500 µm to 5 cm in size) suspended in the water column below the NPGP follow a power law decline with water depth, reaching values <0.001 pieces/m3 and <0.1 µg/m3 in the deep sea. The plastic particles in the NPGP water column are mostly in the size range of particles that are apparently missing from the ocean surface and the polymer composition of plastic in the NPGP water column is similar to that of floating debris circulating in its surface waters (i.e. dominated by polyethylene and polypropylene). Our results further reveal a positive correlation between the amount of plastic debris at the sea surface and the depth-integrated concentrations of plastic fragments in the water column. We therefore conclude that the presence of plastics in the water column below the NPGP is the result of ‘fallout’ of small plastic fragments from its surface waters.

  • Great Pacific Garbage Patch, Plastic pollution, Vertical distribution, vertical transfer

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• The Physical Oceanography of the Transport of Floating Marine Debris

  Topical review
  February 2020, Environmental Research Letters

  Erik van Sebille, Stefano Aliani, Kara Lavender Law, Nikolai Maximenko, José M Alsina, Andrei Bagaev, Melanie Bergmann, Bertrand Chapron, Irina Chubarenko, Andrés Cózar, Philippe Delandmeter, Matthias Egger, Baylor Fox-Kemper, Shungudzemwoyo P Garaba, Lonneke Goddijn-Murphy, Britta Denise Hardesty, Matthew J Hoffman, Atsuhiko Isobe, Cleo E Jongedijk, Mikael L A Kaandorp, Liliya Khatmullina, Albert A Koelmans, Tobias Kukulka, Charlotte Laufkötter, Laurent Lebreton, Delphine Lobelle, Christophe Maes, Victor Martinez-Vicente, Miguel Angel Morales Maqueda, Marie Poulain-Zarcos, Ernesto Rodríguez, Peter G Ryan, Alan L Shanks, Won Joon Shim, Giuseppe Suaria, Martin Thiel, Ton S van den Bremer and David Wichmann

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  • Publication type: Topical review
  • Publication journal: Environmental Research Letters
  • Collaborators: Institute for Marine and Atmospheric Research, Utrecht University (NL), Institute of Marine Sciences—National Research Council (ISMAR-CNR) (IT), Sea Education Association (USA), International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa (USA), Universitat Politècnica de Catalunya (ES), Shirshov Institute of Oceanology, Russian Academy of Sciences (RU), Marine Hydrophysical Institute, Russian Academy of Sciences (RU), Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (DE), Laboratoire d’Océanographie Physique et Spatiale (FR), o. de Biología, Facultad de Cc. del Mar y Ambientales, Universidad de Cádiz (ES), Stichting The Ocean Cleanup (NL), Dept. of Earth, Environmental, and Planetary Sciences, Brown University (USA), Institute at Brown for Environment and Society (USA), Marine Sensor Systems Group, Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg (DE), Environmental Research Institute, University of the Highlands and Islands (UK), Commonwealth Scientific and Industrial Research Organization, Oceans and Atmosphere (AUS), School of Mathematical Sciences, Rochester Institute of Technology (USA), Research Institute for Applied Mechanics, Kyushu University (JP), Department of Civil and Environmental Engineering, Imperial College London (UK), Aquatic Ecology and Water Quality Management Group, Wageningen University & Research (NL), School of Marine Science and Policy, University of Delaware (USA), Climate and Environmental Physics, University of Bern (CH), Ocean and Earth Sciences, University of Southampton (UK) National Physical Laboratory, Teddington (UK), University of Brest, Institut de Recherche pour le Developpement (FR), Remote Sensing Group, Plymouth Marine Laboratory (UK), School of Natural and Environmental Sciences, Newcastle University (UK), Institut de Mécanique des Fluides de Toulouse, University of Toulouse (FR), Laboratoire des Interactions Moléculaires et Réactivité Chimique et Photochimique, University of Toulouse (FR) Jet Propulsion Laboratory, California Institute of Technology (USA), FitzPatrick Institute of African Ornithology, University of Cape Town (ZA), Oregon Institute of Marine Biology, University of Oregon (USA), Oil and POPs Research Group, Korea Institute of Ocean Science and Technology (KR), Facultad Ciencias del Mar, Universidad Católica del Norte (CL), Millennium Nucleus Ecology and Sustainable Management of Oceanic Islands (CL), Centro de Estudios Avanzados en Zonas Áridas (CL), Department of Engineering Science, University of Oxford (UK)
  • Published: 17.02.2020
  • DOI: 10.1088/1748-9326/ab6d7d

  Abstract

  Marine plastic debris floating on the ocean surface is a major environmental problem. However, its distribution in the ocean is poorly mapped, and most of the plastic waste estimated to have entered the ocean from land is unaccounted for. Better understanding of how plastic debris is transported from coastal and marine sources is crucial to quantify and close the global inventory of marine plastics, which in turn represents critical information for mitigation or policy strategies. At the same time, plastic is a unique tracer that provides an opportunity to learn more about the physics and dynamics of our ocean across multiple scales, from the Ekman convergence in basin-scale gyres to individual waves in the surfzone. In this review, we comprehensively discuss what is known about the different processes that govern the transport of floating marine plastic debris in both the open ocean and the coastal zones, based on the published literature and referring to insights from neighbouring fields such as oil spill dispersion, marine safety recovery, plankton connectivity, and others. We discuss how measurements of marine plastics (both in situ and in the laboratory), remote sensing, and numerical simulations can elucidate these processes and their interactions across spatio-temporal scales.

  • fluid dynamics, Marine debris, ocean circulation, Physical oceanography, Remote sensing

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• Rapid Assessment of Floating Macroplastic Transport in the Rhine

  Brief research report article
  January 2020, Frontiers in Marine Science

  Paul Vriend, Caroline van Calcar, Merel Kooi, Harm Landman, Remco Pikaar and Tim van Emmerik

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  • Publication type: Brief research report article
  • Publication journal: Frontiers in Marine Science
  • Collaborators: The Ocean Cleanup, Rotterdam (NL), Hydrology and Quantitative Water Management Group, Wageningen University & Research (NL), Faculty of Civil Engineering and Geosciences (NL), Aquatic Ecology and Water Quality Management Group, Wageningen University & Research (NL), Tauw BV, Capelle aan den IJssel (NL)
  • Publication date: 28.01.2020
  • DOI: 10.3389/fmars.2020.00010

  Abstract

  Most marine litter pollution is assumed to originate from land-based sources, entering the marine environment through rivers. To better understand and quantify the risk that plastic pollution poses on aquatic ecosystems, and to develop effective prevention and mitigation methods, a better understanding of riverine plastic transport is needed. To achieve this, quantification of riverine plastic transport is crucial. Here, we demonstrate how established methods can be combined to provide a rapid and cost-effective characterization and quantification of floating macroplastic transport in the River Rhine. We combine visual observations with passive sampling to arrive at a first-order estimate of macroplastic transport, both in number (10–75 items per hour) and mass per unit of time (1.3–9.7 kg per day). Additionally, our assessment gives insight in the most abundant macroplastic polymer types the downstream reach of the River Rhine. Furthermore, we explore the spatial and temporal variation of plastic transport within the river, and discuss the benefits and drawbacks of current sampling methods. Finally, we present an outlook for future monitoring of major rivers, including several suggestions on how to expand the rapid assessment presented in this paper.

  • Macroplastic, river pollution, Sampling, Visual observation

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• Abundance of Plastic Debris Across European and Asian Rivers

  Letter in peer-reviewed journal
  December 2019, Environmental Research Letters

  C J van Calcar and T H M van Emmerik

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  • Publication type: Letter in peer-reviewed journal
  • Publication journal: Environmental Research Letters
  • Collaborators: The Ocean Cleanup (NL), Geoscience and Remote Sensing, Delft University of Technology (NL), Hydrology and Quantitative Water Management Group, Wageningen University (NL)
  • Published: 11.12.2019
  • DOI: 10.1088/1748-9326/ab5468

  Abstract

  Plastic pollution in the marine environment is an urgent global environmental challenge. Land-based plastics, emitted into the ocean through rivers, are believed to be the main source of marine plastic litter. According to the latest model-based estimates, most riverine plastics are emitted in Asia. However, the exact amount of global riverine plastic emission remains uncertain due to a severe lack of observation. Field-based studies are rare in numbers, focused on rivers in Europe and North America and used strongly varying data collection methods. We present a harmonized assessment of floating macroplastic transport from observations at 24 locations in rivers in seven countries in Europe and Asia. Visual counting and debris sampling were used to assess (1) magnitude of plastic transport, (2) the spatial distribution across the river width, and (3) the plastic polymer composition. Several waterways in Indonesia and Vietnam contain up to four orders of magnitude more plastic than waterways in Italy, France, and The Netherlands in terms of plastic items per hour. We present a first transcontinental overview of plastic transport, providing observational evidence that, for the sampled rivers, Asian rivers transport considerably more plastics towards the ocean. New insights are presented in the magnitude, composition, and spatiotemporal variation of riverine plastic debris. We emphasize the urgent need for more long-term monitoring efforts. Accurate data on riverine plastic debris are extremely important to improve global and local modeling approaches and to optimize prevention and collection strategies.

  • Plastic composition, Plastic pollution, river pollution

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• Measuring Marine Plastic Debris from Space: Initial Assessment of Observation Requirements

  October 2019, article in peer-reviewed journal
  Remote Sensing

  Víctor Martínez-Vicente, James R. Clark, Paolo Corradi, Stefano Aliani, Manuel Arias, Mathias Bochow, Guillaume Bonnery, Matthew Cole, Andrés Cózar, Rory Donnelly, Fidel Echevarría, François Galgani, Shungudzemwoyo P. Garaba, Lonneke Goddijn-Murphy, Laurent Lebreton, Heather A. Leslie, Penelope K. Lindeque, Nikolai Maximenko, François-Régis Martin-Lauzer, Delwyn Moller, Peter Murphy, Lorenzo Palombi, Valentina Raimondi, Julia Reisser, Laia Romero, Stefan G.H. Simis, Sindy Sterckx, Richard C. Thompson, Konstantinos N. Topouzelis, Erik van Sebille, Joana Mira Veiga and A. Dick Vethaak

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  • Publication journal: Remote Sensing
  • Publication type: Article in peer-reviewed journal
  • Collaborators: Plymouth Marine Laboratory, Prospect Place, Plymouth PL1 3DH, UK | European Space Agency—ESTEC, Keplerlaan 1, Postbus 299, 2200 AG Noordwijk, The Netherlands | ISMAR-CNR, Forte Santa Teresa, Pozzuolo di Lerici, 19032 La Spezia, Italy | ARGANS Ltd., Chamberlain House, 1 Research Way, Plymouth PL6 8BU, UK | Section 1.4 Remote Sensing and Geoinformatics, Helmholtz Centre Potsdam—GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany | Airbus Defence and Space—Space Systems 31, rue des Cosmonautes Z.I. du Palays, 31402 Toulouse, France | Dpto. Biología, Campus de Excelencia Internacional del Mar (CEIMAR), Instituto Universitario de Investigaciones Marinas (INMAR), Universidad de Cádiz, E-11510 Puerto Real, Spain | European Association for Remote Sensing Companies (EARSC), Rue de la Loi 26, 1040 Brussels, Belgium | IFREMER, LER/PAC, ZI Furiani, 20600 Bastia, France | The Ocean Cleanup, Batavierenstraat 15, 4-7th floor, 3014 JH Rotterdam, The Netherlands | Marine Sensor Systems Group, Institute for Chemistry and Biology of the Marine Environment (ICBM) - Terramare, University of Oldenburg, Schleusenstr. 1, 26382 Wilhelmshaven, Germany | Environmental Research Institute, University of the Highlands and Islands, Castle Street, Thurso, Caithness KW14 7JD, UK | Dept. of Environment and Health, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands | International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, HI 96822, USA | Department of Electrical, Computer and Software Engineering, The University of Auckland, Auckland 1142, New Zealand | Genwest Inc. 170 W. Dayton St. Suite 106A Edmonds, WA 98020, USA | Marine Debris Division, National Oceanic and Atmospheric Administration, 1305 East-West Highway, Silver Spring, MD 20910, USA | IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy | Oceans Institute, University of Western Australia, Perth, WA 6009, Australia | ISARDSAT, C. Marie Curie, 8-14, A213 08042 Barcelona, Spain | Remote Sensing Unit, Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol, Belgium | International Marine Litter Research Unit, University of Plymouth, Drake Circus, Plymouth, Devon PL4 8AA, UK | Department of Marine Sciences, University of the Aegean, 81100 Mytilene, Greece | Institute for Marine and Atmospheric research, Utrecht University, PO Box 80125, 3508 TC Utrecht, The Netherlands | DELTARES, 2600 MH Delft, The Netherlands
  • Publication date: October 21, 2019
  • DOI: /10.3390/rs11202443

  Abstract

  Sustained observations are required to determine the marine plastic debris mass balance and to support effective policy for planning remedial action. However, observations currently remain scarce at the global scale. A satellite remote sensing system could make a substantial contribution to tackling this problem. Here, we make initial steps towards the potential design of such a remote sensing system by: (1) identifying the properties of marine plastic debris amenable to remote sensing methods and (2) highlighting the oceanic processes relevant to scientific questions about marine plastic debris. Remote sensing approaches are reviewed and matched to the optical properties of marine plastic debris and the relevant spatio-temporal scales of observation to identify challenges and opportunities in the field. Finally, steps needed to develop marine plastic debris detection by remote sensing platforms are proposed in terms of fundamental science as well as linkages to ongoing planning for satellite systems with similar observation requirements.

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• Seine Plastic Debris Transport Tenfolded During Increased River Discharge

  Article in peer-reviewed journal
  October 2019, Frontiers in Marine Science

  Tim van Emmerik, Romain Tramoy, Caroline van Calcar, Soline Alligant, Robin Treilles, Bruno Tassin and Johnny Gasper

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Frontiers in Marine Science
  • DOI: 10.3389/fmars.2019.00642
  • Collaborators: The Ocean Cleanup (NL) Hydrology and Quantitative Water Management Group, Wageningen University and Research (NL), LEESU, Université Paris-Est Créteil (FR), Department of Geoscience and Remote Sensing, Delft University of Technology (NL)
  • Received: 25 May 2019
  • Accepted: 01 October 2019
  • Published: 16 October 2019

  Abstract

  Rivers transport land-based plastic waste into the ocean. Current efforts to quantify riverine plastic emission come with uncertainty as field observations are scarce. One of the challenging aspects is the lack of consistent measurement methods that allow for comparing rivers over space and time. Recent studies have shown that simple visual observations provide a robust first-order characterization of floating and superficially suspended plastic transport, both in quantity, spatiotemporal distribution and composition. For this study, we applied this method to the river Seine, France, to provide new insights in the spatiotemporal variation in riverine plastic transport. First, we studied the response of plastic flow to increased river discharge by comparing measurements taken during low flow and high flow periods. Second, we investigated the variation of riverine plastic transport over the river length to improve our understanding of the origin and fate of riverine plastics. We demonstrate that during a period with higher river discharge, plastic transport increased up to a factor ten at the observation point closest to the river mouth. This suggests that the plastic emission into the ocean from the Seine may also be considerably higher during increased discharge. Upstream of Paris plastic transport increased only with a factor 1.5, suggesting that most plastics originate from Paris or areas further downstream. With this paper we aim to shed additional light on the seasonal variation in riverine plastic transport and its distribution along the river length, which may benefit future long-term monitoring efforts and plastic pollution mitigation strategies.

  • Plastic transport, river pollution

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• Marine Debris Polymers on Main Hawaiian Island Beaches, Sea Surface, and Seafloor

  Article in peer-reviewed journal
  October 2019, Environmental Science & Technology

  Kayla C. Brignac, Melissa R. Jung, Cheryl King, Sarah-Jeanne Royer, Lauren Blickley, Megan R. Lamson, James T. Potemra and Jennifer M. Lynch

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  • Publication type: Publication in peer-reviewed journal
  • Journal: Environmental Science & Technology
  • Collaborators: School of Ocean, Earth Science, and Technology and International Pacific Research Center, University of Hawaii at Manoa (USA), Center for Marine Debris Research, Hawaii Pacific University (USA), Sharkastics, Kihei (USA), Swell Consulting, Paia (USA), Hawaii Wildlife Fund (USA), Chemical Sciences Division, National Institute of Standards and Technology (USA)
  • DOI: 10.1021/acs.est.9b03561
  • Received: 14.06.2019
  • Revised: 06.09.2019
  • Accepted: 25.09.2019

  Abstract

  Polymeric differences of plastic debris were assessed across four compartments of the Main Hawaiian Islands (sea surface, windward beaches, leeward beaches, and seafloor) to better describe sources and fate.
  Plastic debris pieces (n = 4671) were collected from 11 beaches, three sea surface tows, and three seafloor dives. Fourier transform infrared spectroscopy identified the polymers of 3551 pieces. Significant differences (p

  • Marine debris, Polymers, Sea surface, Seafloor

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• The Technological Challenges of Dealing With Plastics in the Environment

  Scientific Commentary
  October 2019, Marine Technology Society Journal

  Sarah-Jeanne Royer and Dimitri D. Deheyn

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  • Publication type: Scientific Commentary
  • Publication journal: Marine Technology and Science
  • Collaborators: Scripps Institution of Oceanography, University of California (USA) and The Ocean Cleanup (NL)
  • DOI: 10.4031/MTSJ.53.5.3

  Abstract

  Plastic pollution has been at the forefront of national news and social media with shocking images of wildlife impacted with plastics. Plastics are found in remote places, from mountain tops to the bottom of the oceans and from the North Pole to Antarctica, and are a sign of the widespread impact of human activities. Plastics that are the most known to the public are the macroplastics (in other words, “the ones we can easily see”); because we use them on a daily basis, they are an integrative part of our life (from the grocery plastic bag to the water bottle or the parts of car or furniture) and are the ones that we consider “disposable” and of single-use (like straws and plastic utensils or cups).

  “And so what?” one might ask. The problem with these plastics is that they were made to last “forever,” meaning that their degradation in the environment is slow, although over the years, these macroplastics undergo weathering and break down in smaller and smaller pieces (called microplastics) that are easier to enter the foodweb. Once in these biological processes that are critical for the well-being of ecosystem functions, the effects of microplastics are still not fully understood, although they are widely accepted to be negative. This is exacerbated by the fact that it is difficult (if not impossible) to remove such microplastics from the environment. Or, at least, the technology of today to do so at such a large scale is still not ready.

  Hence, most of the technological innovations related to plastic targets the macroplastics only; even though this size fraction might not be the most abundant or damaging, at least, it can be removed and hence prevent its further fragmentation in the environment. In this article, we briefly identify the technologies that are proposed to address the issues of macroplastics in the oceans, while addressing the research and policy framework of this global issue in human society.

  • commentary, Plastic pollution

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• Seasonality of Riverine Macroplastic Transport

  Article in peer-reviewed journal
  September 2019, Scientific Reports

  Tim van Emmerik, Emily Strada, Thuy-Chung Kieu-Le, Luan Nguyen and Nicolas Gratiot

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  • Publication type: Article in peer-reviewed journal
  • Publication journal: Scientific Reports
  • DOI: 10.1038/s41598-019-50096-1
  • Received: 12.03.2019
  • Aceepted: 06.09.2019
  • Published: 19.09.2019
  • Collaborators: Stichting The Ocean Cleanup (NL), Hydrology and Quantitative Water Management Group, Wageningen University (NL), CARE, Ho Chi Minh City University of Technology (VN), University of Grenoble Alpes (FR), Aix-Marseille University, Mediterranean Institute of Oceanography, Université de Toulon (FR), Faculty of Geology and Petroleum Engineering, Ho Chi Minh City University of Technology (VN)

  Abstract

  Marine plastic pollution is an increasing environmental threat. Although it is assumed that most marine plastics are transported from land to the ocean through rivers, only limited data on riverine plastic transport exists. Recently, new methods have been introduced to characterize riverine plastics consistently through time and space. For example, combining visual counting observations and plastic debris sampling can provide order of magnitude estimations of plastic transport through a river. In this paper, we present findings from multi-season measurement campaign in the Saigon River, Vietnam. For the first time, we demonstrate that macroplastic transport exhibits strong temporal variation. The monthly averaged plastic transport changes up to a factor five within the measurement period. As it is unclear what drives the variation in plastic transport, relations between rainfall, river discharge, presence of organic material and plastic transport have been explored. Furthermore, we present new findings on the cross-sectional and vertical distribution of riverine plastic transport. With this paper we present new insights in the origin and fate of riverine plastic transport, emphasizing the severity of the emerging thread of plastic pollution on riverine ecosystems.

  • Macroplastic, Plastic transport, river pollution

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• A Global Mass Budget for Positively Buoyant Macroplastic Debris in the Ocean

  Article in peer-reviewed journal
  September 2019, Scientific Reports

  Laurent Lebreton, Matthias Egger and Boyan Slat

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  • Publication type: Article in peer-reviewed journal
  • Journal: Scientific Reports
  • DOI: 10.1038/s41598-019-49413-S
  • Collaborators: The Ocean Cleanup (NL), The Modelling House (NZ)
  • Received: 09.10.2018
  • Accepted: 24.08.2019
  • Published: 12.09.2019

  Abstract

  Predicted global figures for plastic debris accumulation in the ocean surface layer range on the order of hundreds of thousands of metric tons, representing only a few percent of estimated annual emissions into the marine environment. The current accepted explanation for this difference is that positively buoyant macroplastic objects do not persist on the ocean surface. Subject to degradation into microplastics, the major part of the mass is predicted to have settled below the surface. However, we argue that such a simple emission-degradation model cannot explain the occurrence of decades-old objects collected by oceanic expeditions. We show that debris circulation dynamics in coastal environments may be a better explanation for this difference. The results presented here suggest that there is a significant time interval, on the order of several years to decades, between terrestrial emissions and representative accumulation in offshore waters. Importantly, our results also indicate that the current generation of secondary microplastics in the global ocean is mostly a result of the degradation of objects produced in the 1990s and earlier. Finally, we propose a series of future emission scenarios until 2050, discussing the necessity to rapidly reduce emissions and actively remove waste accumulated in the environment to mitigate further microplastic contamination in the global ocean.

  • Macroplastic, Marine debris, Plastic distribution

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• Riverine Plastic Litter Monitoring Using Unmanned Aerial Vehicles (UAVs)

  Article in peer-reviewed journal
  August 2019, Remote Sensing

  Marlein Geraeds, Tim van Emmerik, Robin de Vries and Mohd Shahrizal bin Ab Razak

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  • Publication type: Article in peer-reviewed journal
  • Journal: Remote Sensing
  • Collaborators: The Ocean Cleanup (NL), Faculty of Civil Engineering and Geosciences, Delft University of Technology (NL), Hydrology and Quantitative Water Management Group, Wageningen University (NL), Faculty of Engineering, Department of Civil Engineering, Universiti Putra Malaysia (MY)
  • DOI: 10.3390/rs11172045
  • Received: 21.07.2019
  • Accepted: 28.08.2019
  • Published: 30.08.2019

  Abstract

  Plastic debris has become an abundant pollutant in marine, coastal and riverine environments, posing a large threat to aquatic life. Effective measures to mitigate and prevent marine plastic pollution require a thorough understanding of its origin and eventual fate. Several models have estimated that land-based sources are the main source of marine plastic pollution, although field data to substantiate these estimates remain limited. Current methodologies to measure riverine plastic transport require the availability of infrastructure and accessible riverbanks, but, to obtain measurements on a higher spatial and temporal scale, new monitoring methods are required. This paper presents a new methodology for quantifying riverine plastic debris using Unmanned Aerial Vehicles (UAVs), including a first application on Klang River, Malaysia. Additional plastic measurements were done in parallel with the UAV-based approach to make comparisons between the two methods. The spatiotemporal distribution of the plastics obtained with both methods show similar patterns and variations. With this, we show that UAV-based monitoring methods are a promising alternative for currently available approaches for monitoring riverine plastic transport, especially in remote and inaccessible areas.

  • Hydrology, Marine debris, Plastic pollution, Unmanned aerial vehicles

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• Toward the Integrated Marine Debris Observing System

  Article in peer-reviewed journal
  August 2019, Frontiers in Marine Science

  Nikolai Maximenko, Paolo Corradi, Kara Lavender Law, Erik Van Sebille, Shungudzemwoyo P. Garaba, Richard Stephen Lampitt, Francois Galgani, Victor Martinez-Vicente, Lonneke Goddijn-Murphy, Joana Mira Veiga, Richard C. Thompson, Christophe Maes, Delwyn Moller, Carolin Regina Löscher, Anna Maria Addamo, Megan Rose Lamson, Luca R Centurioni, Nicole Rita Posth, Rick Lumpkin, Matteo Vinci, Ana Maria Martins, Catharina Diogo Pieper, Atsuhiko Isobe, Georg Hanke, Margo Edwards, Irina P. Chubarenko, Ernesto Rodriguez, Stefano Aliani, Manuel Arias, Gregory P. Asner, Alberto Brosich, James T. Carlton, Yi Chao, Anna-Marie Cook, Andrew B. Cundy, Tamara S. Galloway, Alessandra Giorgetti, Gustavo Jorge Goni, Yann Guichoux, Linsey E. Haram, Britta Denise Hardesty, Neil Holdsworth, Laurent Lebreton, Heather A. Leslie, Ilan Macadam-Somer, Thomas Mace, Mark Manuel, Robert Marsh, Elodie Martinez, Daniel J. Mayor, Morgan Le Moigne, Maria Eugenia Molina Jack, Matt Charles Mowlem, Rachel W. Obbard, Katsiaryna Pabortsava, Bill Robberson, Amelia-Elena Rotaru, Gregory M. Ruiz, Maria Teresa Spedicato, Martin Thiel, Alexander Turra and Chris Wilcox

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  • Publication type: Article in peer-reviewed journal
  • Journal: Frontiers in Marine Science
  • DOI: 10.3389/fmars.2019.00447
  • Collaborators: International Pacific Research Center, University of Hawaii (USA), European Space Research and Technology Centre (NL), Sea Education Association (USA), Institute for Marine and Atmospheric Research, Utrecht University (NL), Marine Sensor Systems, Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg (DE), National Oceanography Centre (UK), Département Océanographie et Dynamique des Écosystémes, Institut Français de Recherche pour l'Exploitation de la Mer (FR), Plymouth Marine Laboratory (UK), Environmental Research Institute, University of the Highlands and Islands (UK), Deltares (NL), University of Plymouth (UK), Laboratoire d'Océanographie Physique et Spatiale, Institute of Research for Development (FR), Remote Sensing Solutions (USA), Department of Biology, Faculty of Science, University of Southern Denmark (DK), European Commission, Joint Research Centre (IT), Hawai‘i Wildlife Fund (USA), Scripps Institution of Oceanography, University of California (USA), Department of Geosciences and Natural Resource Management, University of Copenhagen (DK), Atlantic Oceanographic and Meteorological Laboratory (NOAA)(USA), Sezione di Oceanografia, Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (IT), Department of Oceanography and Fisheries, University of the Azores (PT), Research Institute for Applied Mechanics, Kyushu University (JP), Applied Research Laboratory, Hawaii Institute of Geophysics and Planetology, University of Hawaii (USA), P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences (RU), NASA Jet Propulsion Laboratory, California Institute of Technology (USA), CNR Institute of Marine Sciences (IT), Argans, Plymouth, United Kingdom, 28 Center for Global Discovery and Conservation Science (USA), Mystic Seaport Program, Williams College (USA), Environmental Protection Agency (EPA)(USA), School of Ocean and Earth Science, National Oceanography Centre, University of Southampton (UK), College of Life and Environmental Science, University of Exeter (UK), eOdyn (FR), Smithsonian Environmental Research Center (USA), CSIRO Oceans and Atmosphere (AUS), International Council for the Exploration of the Sea (DK), Stichting The Ocean Cleanup (NL) Department of Environment and Health, Vrije Universiteit Amsterdam (NL), Algalita Marine Research and Education, Long Beach (USA), Mace Geospatial, LLC (USA), Freestone Environmental Services (USA), National Oceanic and Atmospheric Administration (USA), Carl Sagan Center, SETI Institute (USA), COISPA Tecnologia and Ricerca (IT), Facultad Ciencias del Mar, Universidad Católica del Norte (CL), Oceanographic Institute, Universidade de São Paulo (BR)
  • Received: 21.11.2018
  • Accepted: 05.07.2019
  • Published: 28.08.2019

  Abstract

  Plastics and other artificial materials pose new risks to the health of the ocean. Anthropogenic debris travels across large distances and is ubiquitous in the water and on shorelines, yet, observations of its sources, composition, pathways, and distributions in the ocean are very sparse and inaccurate. Total amounts of plastics and other man-made debris in the ocean and on the shore, temporal trends in these amounts under exponentially increasing production, as well as degradation processes, vertical fluxes, and time scales are largely unknown. Present ocean circulation models are not able to accurately simulate drift of debris because of its complex hydrodynamics. In this paper we discuss the structure of the future integrated marine debris observing system (IMDOS) that is required to provide long-term monitoring of the state of this anthropogenic pollution and support operational activities to mitigate impacts on the ecosystem and on the safety of maritime activity. The proposed observing system integrates remote sensing and in situ observations. Also, models are used to optimize the design of the system and, in turn, they will be gradually improved using the products of the system. Remote sensing technologies will provide spatially coherent coverage and consistent surveying time series at local to global scale. Optical sensors, including high-resolution imaging, multi- and hyperspectral, fluorescence, and Raman technologies, as well as SAR will be used to measure different types of debris. They will be implemented in a variety of platforms, from hand-held tools to ship-, buoy-, aircraft-, and satellite-based sensors. A network of in situ observations, including reports from volunteers, citizen scientists and ships of opportunity, will be developed to provide data for calibration/validation of remote sensors and to monitor the spread of plastic pollution and other marine debris. IMDOS will interact with other observing systems monitoring physical, chemical, and biological processes in the ocean and on shorelines as well as the state of the ecosystem, maritime activities and safety, drift of sea ice, etc. The synthesized data will support innovative multi-disciplinary research and serve a diverse community of users.

  • Marine debris, Remote sensing, research methodology, Visual observation

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• Risk assessment of plastic pollution on marine diversity in the Mediterranean Sea

  August 2019, article in peer-reviewed journal
  Science of The Total Environment

  Montserrat Compa, Carme Alomar, Chris Wilcox, Erik van Sebille, Laurent Lebreton, Britta Denise Hardesty and Salud Deudero

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  • Publication journal: Science of The Total Environment
  • Publication type: Article in peer-reviewed journal
  • Collaborators: Instituto Español de Oceanografía, Centro Oceanográfico de Baleares, Palma 07015, Spain | Commonwealth Scientific and Industrial Research Organization, Oceans and Atmosphere Business Unit, Hobart, Tasmania. 7000, Australia | Grantham Institute, Imperial College London, London SW7 2AZ, United Kingdom | Institute for Marine and Atmospheric Research, Utrecht University, Utrecht, Netherlands | The Ocean Cleanup Foundation, Rotterdam 2014, Netherlands
  • Publication date: August 15, 2019
  • DOI: /10.1016/j.scitotenv.2019.04.355

  Abstract

  Plastic marine pollution is an increasing threat to global marine diversity. Quantifying this threat is particularly difficult and complex, especially when evaluating multiple species with different ecological requirements. Here, we examine the semi-enclosed basin of the Mediterranean Sea where the inputs of plastic pollution and its impact on marine diversity are still widely unknown. Eighty-four species from six taxonomic classes were evaluated to assess the risk of ingesting plastic marine debris, integrating inter-specific factors such as plastic exposure rates and life history traits (e.g., motility, habitat, and body size). Species were modelled within a spatial context to identify and estimate their exposure to plastic ingestion across the Mediterranean Sea using literature data, species distribution maps and plastic dispersion models. Our approach identified hotspots for the risk of plastic ingestion across multiple taxa in the Mediterranean Sea, highlighting that coastal species are at higher risk of ingesting plastic in the marine environment than open-sea species. The plastic exposure analysis indicated that species with larger home ranges were more at risk of exposure with increased distances while local species were more likely to be exposed to plastic closer to the centre of their home range location. The approach used in this study can be applied to support management and mitigation efforts throughout the Mediterranean Sea and in other geographic regions to minimize the impact of plastic pollution on marine diversity.

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• Riverine Plastic Emission from Jakarta into the Ocean

  Article in peer-reviewed journal
  July 2019, Environmental Research Letters

  Tim van Emmerik, Michelle Loozen, Kees van Oeveren, Frans Buschman and Geert Prinsen

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  • Publication type: Article in peer-reviewed journal
  • Journal: Environmental Research Letters
  • Collaborators: The Ocean Cleanup (NL), Hydrology and Quantitative Water Management Group, Wageningen University (NL), Deltares (NL)
  • Submitted: 13.05.2019
  • Revised: 03.07.2019
  • Accepted: 10.07.2019
  • Published: 13.08.2019

  Abstract

  Plastic pollution in aquatic environments is an increasing global risk. In recent years, marine plastic pollution has been studied to a great extent, and it has been hypothesized that land-based plastics are its main source. Global modeling efforts have suggested that rivers in South East Asia are in fact the main contributors to plastic transport from land to the oceans. However, due to a lack of plastic transport observations, the origin and fate of riverine plastic waste is yet unclear. Here, we present results from a first assessment of riverine macroplastic emission from rivers and canals that run through a densely populated coastal urban city. Using a combination of field measurements, empirical relations and hydraulic modeling, we provide an estimate of total riverine plastic export originating from Jakarta, Indonesia, into the ocean. Furthermore, we provide insights in its composition, and variation in time and space. We found that most macroplastics in Jakarta consists of films and foils. We estimate that 2.1 × 103 tonnes of plastic waste, is transported from land to sea annually, equaling 3% of the total annual unsoundly disposed plastic waste in the Jakarta area.

  • Anthropocene, Hydrology, Macroplastic, Marine debris, Urban river

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• Joint effort among research infrastructures to quantify the impact of plastic debris in the ocean

  May 2019, environmental research letter
  IOP Science

  Diarmuid Ó Conchubhair, Deirdre Fitzhenry, Amy Lusher, Andrew L King, Tim van Emmerik, Laurent Lebreton, Constanza Ricaurte-Villota, Luisa Espinosa3 and Eleanor O'Rourke

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  • Publication journal: IOP Science
  • Publication type: Environmental research letter
  • Collaborators: Marine Institute (MI) Ireland | Norwegian Institute for Water Research (NIVA), Norway | INVEMAR, Colombia | The Ocean Cleanup, The Netherlands
  • Publication date: May 22, 2019
  • DOI: 10.1088/1748-9326/ab17ed

  Abstract

  Marine debris is one of the most significant problems facing the marine environment, endangering wildlife, polluting oceans and is an issue which holds global significance. Plastics constitute a large proportion of marine debris, and their persistence can cause a number of negative consequences for biota and the environment, including entanglement and ingestion, which can lead to mortality. Most plastics never biodegrade and instead break down into smaller pieces which are more difficult to monitor and eventually become so small (micro and nanoplastics), that they are challenging to observe or intercept in the ocean. Marine-based Research Infrastructures (RIs) monitor several environmental parameters and are situated around the globe; however, none of these are routinely monitoring marine debris or plastics. Currently, the only infrastructures in place with regard to marine debris are ‘physical debris interception infrastructure’ in the form of barriers constructed to prevent marine debris from entering the ocean. Several knowledge gaps and restraints exist within current in situ infrastructure including technological immaturity, diverse methodologies and lack of data harmonisation. Nevertheless, marine RIs could monitor microplastics within the water column on a long-term basis and initial steps towards developing technology are promising.

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• Cetacean Sightings within the Great Pacific Garbage Patch

  Scientific note
  April 2019, Marine Biodiversity

  Susan E. Gibbs, Chandra P. Salgado Kent, Boyan Slat, Damien Morales, Leila Fouda and Julia Reisser

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  • Publication type: Scientific note
  • Journal: Marine Biodiversity
  • Collaborators: The Ocean Cleanup Foundation (NL), Centre for Marine Science and Technology, Curin University (AUS), Oceans Blueprint (AUS), Centre for Marine Ecosystems Research (AUS), Blue Planet (AUS), Minderoo Foundation (AUS), School of Biological and Chemical Studies, Queen Mary University (UK), UWA Oceans Institute, University of Western Australia (AUS).
  • DOI: 10.1007/s12526-019-00952-0
  • Submitted: 12.07.2018
  • Accepted: 15.03.2019
  • Published: 09.04.2019

  Abstract

  Here, we report cetacean sightings made within a major oceanic accumulation zone for plastics, often referred to as the ‘Great Pacific Garbage Patch’ (GPGP). These cetacean records occurred in October 2016 and were made by sensors and trained observers aboard a Hercules C-130 aircraft surveying the GPGP at 400 m height and 140 knots speed. Four sperm whales (including a mother and calf pair), three beaked whales, two baleen whales, and at least five other cetaceans were observed. Many surface drifting plastics were also detected, including fishing nets, ropes, floats and fragmented debris. Some of these objects were close to the sighted mammals, posing entanglement and ingestion risks to animals using the GPGP as a migration corridor or core habitat. Our study demonstrates the potential exposure of several cetacean species to the high levels of plastic pollution in the area. Further research is required to evaluate the potential effects of the GPGP on marine mammal populations inhabiting the North Pacific.

  • Aerial survey, Cetaceans, Great Pacific Garbage Patch, Marine mammals, Plastic pollution

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• A Methodology to Characterize Riverine Macroplastic Emission Into the Ocean

  Article in peer-reviewed journal
  October 2018, Frontiers in Marine Science

  Tim van Emmerik, Thuy-Chung Kieu-Le, Michelle Loozen, Kees van Oeveren, Emilie Strady, Xuan-Thanh Bui, Matthias Egger, Johnny Gasperi, Laurent Lebreton, Phuoc-Dan Nguyen, Anna Schwarz, Boyan Slat and Bruno Tassin

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  • Publication type: Article in peer-reviewed journal
  • Journal: Frontiers in Marine Science
  • Collaborators: The Ocean Cleanup Foundation (NL), CARE, Ho Chi Min University of Technology (VN), Faculty of Geology and Petroleum Engineering, Ho Chi Minh City University of Technology (VN), CNRS, IRD, Grenoble INP, IGE, University of Grenoble Alpes (FR), Faculty of Environment and Natural Resources, Ho Chi Minh City University of Technology (VN), Laboratoire Eau, Environnement, Systèmes Urbains (LEESU), Université Paris-Est (FR), The Modelling House Limited (NZ).
  • DOI: 10.3389/fmars.2018.00372
  • Submitted: 25.06.2018
  • Accepted: 25.09.2018
  • Published: 17.10.2018

  Abstract

  Land-based macroplastic is considered one of the major sources of marine plastic debris. However, estimations of plastic emission from rivers into the oceans remain scarce and uncertain, mainly due to a severe lack of standardized observations. To properly assess global plastic fluxes, detailed information on spatiotemporal variation in river plastic quantities and composition are urgently needed. In this paper, we present a new methodology to characterize riverine macroplastic dynamics. The proposed methodology was applied to estimate the plastic emission from the Saigon River, Vietnam. During a 2-week period, hourly cross-sectional profiles of plastic transport were made across the river width. Simultaneously, sub-hourly samples were taken to determine the weight, size and composition of riverine macroplastics (>5 cm). Finally, extrapolation of the observations based on available hydrological data yielded new estimates of daily, monthly and annual macroplastic emission into the ocean. Our results suggest that plastic emissions from the Saigon River are up to four times higher than previously estimated. Importantly, our flexible methodology can be adapted to local hydrological circumstances and data availability, thus enabling a consistent characterization of macroplastic dynamics in rivers worldwide. Such data will provide crucial knowledge for the optimization of future mediation and recycling efforts.

  • research methodology, river pollution

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• Sensing Ocean Plastics with an Airborne Hyperspectral Shortwave IR Imager

  Article in peer reviewed journal
  September 2018, Environmental Science & Technologys

  Shungudzemwoyo P. Garaba, Jen Aitken, Boyan Slat, Heidi M. Dierssen, Laurent Lebreton, Oliver Zielinski and Julia Reisser

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  • Publication type: Article in peer-reviewed journal
  • Journal: Environmental Science & Technology
  • Collaborators: The Ocean Cleanup Foundation (NL), Department of Marine Sciences, University of Connecticut (US), Marine Sensor Systems Group, Carl von Ossietzky University of Oldenburg (DE), Teledyne Optech (USA), The Modelling House (NZ), Australian Institute of Marine Science, Indian Ocean Marine Research Centre (AUS), Red Sea Research Center, King Abdullah University of Science and Technology (SA).
  • DOI: 10.1021/acs.est.8b02855
  • Submitted: 28.05.2018
  • Accepted: 20.08.2018
  • Published: 25.09.2018

  Abstract

  Here, we present a proof-of-concept on remote sensing of ocean plastics using airborne shortwave IR (SWIR) imagery. We captured red, green, and blue (RGB) and hyperspectral SWIR imagery with equipment mounted on a C-130 aircraft surveying the “Great Pacific Garbage Patch” at a height of 400 m and a speed of 140 knots. We recorded the position, size, color, and type (container, float, ghost net, rope, and unknown) of every plastic piece identified in the RGB mosaics. We then selected the top 30 largest items within each of our plastic type categories (0.6−6.8 m in length) to investigate SWIR spectral information obtained with a SASI-600 imager (950−2450 nm). Our analyses revealed unique SWIR spectral features common to plastics. The SWIR spectra obtained (N = 118 items) were quite similar both in magnitude and shape. Nonetheless, some spectral variability was observed, likely influenced by differences in the object optical properties, the level of water submersion, and an intervening atmosphere. Our simulations confirmed that the ∼1215 and ∼1732 nm absorption features have potential applications in detecting ocean plastics from spectral information. Our study also explores the potential of SWIR remote sensing technology for detecting and quantifying ocean plastics, thus providing relevant information to those developing better monitoring solutions for ocean plastic pollution. Ocean plastic can persist in sea surface waters, eventually accumulating in remote areas of the world’s oceans. Here we characterize and quantify a major ocean plastic accumulation zone formed in subtropical waters between California and Hawaii: The Great Pacific Garbage Patch (GPGP). Our model, calibrated with data from multi-vessel and aircraft surveys, predicted at least 79 (45-129) thousand tonnes of ocean plastic are floating inside an area of 1.6 million km2; a figure four to sixteen times higher than previously reported. We explain this difference through the use of more robust methods to quantify larger debris. Over three-quarters of the GPGP mass was carried by debris larger than 5 cm and at least 46% was comprised of fishing nets. Microplastics accounted for 8% of the total mass but 94% of the estimated 1.8 (1.1-3.6) trillion pieces floating in the area. Plastic collected during our study has specific characteristics such as small surface-to-volume ratio, indicating that only certain types of debris have the capacity to persist and accumulate at the surface of the GPGP. Finally, our results suggest that ocean plastic pollution within the GPGP is increasing exponentially and at a faster rate than in surrounding waters.

  • Aerial survey, Marine debris, Oceanography, Plastic pollution, Remote sensing

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• Evidence that the Great Pacific Garbage Patch is Rapidly Accumulating Plastic

  Article in peer reviewed journal
  March 2018, Scientific Reports

  Laurent CM Lebreton, Boyan Slat, Francesco Ferrari, Bruno Sainte-Rose, Jen Aitken, Bob Marthouse, Sara Hajbane, Serena Cunsolo, Anna Schwarz, Aurore Levivier, Kim Noble, Pavla Debeljak, Hanna Maral, Rosanna Schoeneich-Argent, Roberto Brambini and Julia Reisser

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  • Publication type: Article in peer-reviewed journal
  • Journal: Scientific Reports
  • Collaborators: The Ocean Cleanup Foundation (NL), The Modelling House (NZ), Teledyne Optech (USA), School of Civil, Engineering and Surveying, Faculty of Technology, University of Portsmouth (UK), Department of Biology, Marine Biology and Environmental Science, Roger Williams University (USA), Laboratoire d'Océanographie Microbienne (LOMIC), Sorbonne Universités, Paris (FR), Department of Civil, Geo and Environmental Engineering, Technical University Munich, (DE), ICBM-Terramare, Carl von Ossietzky University Oldenburg, (DE), Civil Engineering Department, Aalborg University, (DK)
  • DOI: 10.1038/s41598-018-22939-w
  • Submitted: 17.10.2017
  • Accepted: 05.03.2018
  • Published: 22.03.2018

  Abstract

  Ocean plastic can persist in sea surface waters, eventually accumulating in remote areas of the world’s oceans. Here we characterize and quantify a major ocean plastic accumulation zone formed in subtropical waters between California and Hawaii: The Great Pacific Garbage Patch (GPGP). Our model, calibrated with data from multi-vessel and aircraft surveys, predicted at least 79 (45-129) thousand tonnes of ocean plastic are floating inside an area of 1.6 million km2; a figure four to sixteen times higher than previously reported. We explain this difference through the use of more robust methods to quantify larger debris. Over three-quarters of the GPGP mass was carried by debris larger than 5 cm and at least 46% was comprised of fishing nets. Microplastics accounted for 8% of the total mass but 94% of the estimated 1.8 (1.1-3.6) trillion pieces floating in the area. Plastic collected during our study has specific characteristics such as small surface-to-volume ratio, indicating that only certain types of debris have the capacity to persist and accumulate at the surface of the GPGP. Finally, our results suggest that ocean plastic pollution within the GPGP is increasing exponentially and at a faster rate than in surrounding waters.

  • Computational science, Great Pacific Garbage Patch, Marine debris, Oceanography, Plastic pollution

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• Microplastic sampling with the AVANI trawl compared to two neuston trawls in the Bay of Bengal and South Pacific

  January 2018, article in peer-reviewed journal
  Environmental Pollution

  Marcus Eriksen, Max Liboiron, Tim Kiessling, Louis Charron, Abigail Alling, Laurent Lebreton, Heather Richards, Barent Roth, Nicolas C. Ory, Valeria Hidalgo-Ruz, Erika Meerhoff, Carolynn Box, Anna Cummins and Martin Thiel

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  • Publication journal: Environmental Pollution
  • Publication type: Article in peer-reviewed journal
  • Collaborators: 5 Gyres Institute, 3131 Olympic Blvd #302, Santa Monica, CA, 90404, USA | Memorial University of Newfoundland, Geography Department, St. John's, NL, Canada | Facultad Ciencias del Mar, Universidad Católica del Norte, Larrondo, 1281, Coquimbo, Chile | Millennium Nucleus Ecology and Sustainable Management of Oceanic Island (ESMOI), Coquimbo, Chile | Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Coquimbo, Chile | Biosphere Foundation, United States | The Ocean Cleanup, Delft, The Netherlands | San Francisco State University, San Francisco, CA, United States | The New School, New York, NY, United States
  • Publication date: January 2018
  • DOI: /10.1016/j.envpol.2017.09.058

  Abstract

  Many typical neuston trawls can only be used during relatively calm sea states and slow tow speeds. During two expeditions to the Bay of Bengal and the eastern South Pacific we investigated whether the new, high-speed AVANI trawl (All-purpose Velocity Accelerated Net Instrument) collects similar amounts and types of microplastics as two established scientific trawl designs, the manta trawl and the DiSalvo neuston net. Using a 335 μm net, the AVANI trawl can collect microplastics from the sea surface at speeds up to 8 knots as it “skis” across the surface, whereas the manta and DiSalvo neuston trawls must be towed slowly in a less turbulent sea state and often represent shorter tow lengths. Generally, the AVANI trawl collected a greater numerical abundance and weight of plastic particles in most size classes and debris types than the manta trawl and DiSalvo neuston net, likely because these trawls only skim the surface layer while the AVANI trawl, moving vertically in a random fashion, collects a “deeper” sample, capturing the few plastics that float slightly lower in the water column. However, the samples did not differ enough that results were significantly affected, suggesting that studies done with these different trawls are comparable. The advantage of the AVANI trawl over traditional research trawls is that it allows for collection on vessels underway at high speeds and during long transits, allowing for a nearly continuous sampling effort over long distances. As local surface currents make sea surface abundance widely heterogeneous, widely spaced short-tow trawls, such as the manta and DiSalvo trawls, can catch or miss hotspots or meso-scale variability of microplastic accumulations, whereas the AVANI trawl, if utilized for back-to-back tows of intermediate distances (5–10 km), can bridge variable wind conditions and debris concentrations potentially reducing variance and provide a greater resolution of spatial distribution.

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• Pollutants in Plastics within the North Pacific Subtropical Gyre

  Article in peer reviewed journal
  December 2017, Environmental Science & Technology

  Qiqing Chen, Julia Reisser, Serena Cunsolo, Christiaan Kwadijk, Michiel Kotterman, Maira Proietti, Boyan Slat, Francesco F. Ferrari, Anna Schwarz, Aurore Levivier, Daqiang Yin, Henner Hollert and Albert A. Koelmans

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  • Publication type: Article in peer-reviewed journal
  • Journal: Environmental Science & Technology
  • Collaborators: The Ocean Cleanup Foundation (NL), Department of Ecosystem Analysis, Institute for Environmental Research, ABBt – Aachen Biology and Biotechnology, RWTH Aachen University (DE), State Key Laboratory of Estuarine and Coastal Research, East China Normal University (CN), School of Civil Engineering and Surveying, Faculty of Technology, Wageningen Marine Research, Wageningen University & Research (NL), Instituto de Oceanografia, Universidade Federal do Rio Grande (BR), State Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering (CN), Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University & Research (NL)
  • DOI: 10.1021/acs.est.7b04682
  • Submitted: 11.09.2017
  • Accepted: 29.11.2017
  • Published: 21.12.2017

  Abstract

  Here we report concentrations of pollutants in floating plastics from the North Pacific accumulation zone (NPAC). We compared chemical concentrations in plastics of different types and sizes, assessed ocean plastic potential risks using sediment quality criteria, and discussed the implications of our findings for bioaccumulation. Our results suggest that at least a fraction of the NPAC plastics is not in equilibrium with the surrounding seawater. For instance, ‘hard plastic’ samples had significantly higher PBDE concentrations than ‘nets and ropes’ samples, and 29% of them had PBDE composition similar to a widely used flame-retardant mixture. Our findings indicate that NPAC plastics may pose a chemical risk to organisms as 84% of the samples had at least one chemical exceeding sediment threshold effect levels. Furthermore, our surface trawls collected more plastic than biomass (180 times on average), indicating that some NPAC organisms feeding upon floating particles may have plastic as a major component of their diets. If gradients for pollutant transfer from NPAC plastic to predators exist (as indicated by our fugacity ratio calculations), plastics may play a role in transferring chemicals to certain marine organisms.

  • Bioaccumulation, Chemical oceanography, Ecotoxicology, Marine debris, Microplastics, Persistent organic pollutants, Plastic pollution, Risk analysis

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• Quantification of Medium and Large Debris in the Great Pacific Garbage Patch Using Visual Observations from Aerial Surveys

  Technical Report
  September 24, 2017

  Salgado Kent C, Reisser J, Gibbs SE, Fouda L, Morales D and Kniest H

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  • Type: Technical report
  • Collaborators: Centre for Marine Science and Technology, Curtin University (Australia), The Ocean Cleanup (The Netherlands), University of New Castle (Australia)
  • Support provided from: Teledyne Optech, International Air Response, and Moffett Federal Airfield.
  • DOI: 10.13140/RG.2.2.10025.29287

  Abstract

  The Ocean Cleanup Aerial Expedition used visual observation teams and sensors installed on the aircraft to detect floating debris within the so-called Great Pacific Garbage Patch. This document specifically reports on the visual observations conducted during these aerial surveys in October 2016.

  • Aerial survey, Great Pacific Garbage Patch, Plastic pollution, Visual observation

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• Using Numerical Model Simulations to Improve the Understanding of Micro-plastic Distribution and Pathways in the Marine Environment

  Article in peer reviewed journal
  January 2017, Frontiers Marine Sciences

  Britta D. Hardesty, Joseph Harari, Atsuhiko Isobe, Laurent Lebreton, Nikolai Maximenko, James T. Potemra, Erik van Sebille, Dick Vethaak and Chris Wilcox

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  • Publication type: Article in peer-reviewed journal
  • Journal: Frontiers Marine Sciences (2017)
  • Collaborators: Commonwealth Scientific and Research Organization (Australia), São Paulo University (Brazil), Kyusshu Universoty (Japan), The Modeling House (New Zealand), University of Hawaii (USA), Imperial College London (United Kingdom), Deltares (The Netherlands), Vrije University (The Netherlands)
  • DOI: 10.3389/fmars.2017.00030
  • Submitted: 01.11.2016
  • Accepted: 25.01.2017

  Abstract

  Numerical modelling is one of the key tools with which we can gain insight into the distribution of marine litter, especially micro-plastics. Over the past decade, a series of numerical simulations have been constructed that specifically target floating marine litter, based on ocean models of various complexity. Some of these models include the effects of currents, waves and wind as well as a series of processes that impact how particles interact with ocean currents, including fragmentation and degradation. Here, we give an overview of these models, including their spatial and temporal resolution, limitations, availability, and what we have learned from them. Then we focus on floating marine micro-plastics (<5mm diameter) and we make recommendations for experimental research efforts that can improve the skill of the models by increasing our understanding of the processes that govern the dispersion of marine litter. In addition, we highlight the importance of knowing accurately the sources or entry points of marine plastic debris, including potential sources that have not been incorporated in previous studies (e.g. atmospheric contributions). Finally, we identify information gaps and priority work areas for research. We also highlight the need for appreciating and acknowledging the uncertainty that persists regarding the movement, transportation and accumulation of anthropogenic litter in the marine environment.

  • Accumulation modeling, Fluxes, Fragmentation, Marine debris, Microplastics, Numerical modeling

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• Extracting DNA from ocean microplastics: a method comparison study

  Article in peer reviewed journal
  November 2016, Analytical Methods 9

  Pavla Debeljak, Maria Pinto, Julia Reisser, Francesco F. Ferrari, Ben Abbas, Mark C. M. van Loosdrecht, Boyan Slat and Gerhard J. Herndl

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  • Publication type: Article in peer-reviewed journal
  • Journal: Analytical Methods 9, 1521-1526 (2017)
  • Collaborators: University of Vienna (Austria), Universidade Federal do Rio Grande (Brazil), Delft University of Technology (The Netherlands), NIOZ Netherlands Institute of Sea Research (The Netherlands)
  • DOI: 10.1039/C6AY03119F
  • Submitted: 17.11.2016
  • Accepted: 20.11.2016
  • Published: 21.11.2016

  Abstract

  The ubiquity of plastics in oceans worldwide raises concerns about their ecological implications. Suspended microplastics (<5 mm) can be ingested by a wide range of marine organisms and may accumulate up the food web along with associated chemicals. Additionally, plastics provide a stable substrate to a wide range of organisms and, owing to their widespread dispersal, may function as vectors for harmful and invasive species. Despite the growing application of molecular techniques to study ocean microplastic colonizers, to date there is no comparative study on DNA extraction methods for ocean plastic biofilms. The present study aims to fill this gap by comparing DNA yield, amplification efficiency, costs and processing time of different DNA extraction techniques applied to oceanic microplastics. DNA was extracted with five methods (four extraction kits, and standard phenol:chloroform purification) using two mechanical lysis techniques (bead beating and cryogenic grinding with liquid nitrogen) applied to three plastic quantities (1, 15, and 50 fragments per extraction) and size classes (0.05–0.15 and 0.15–0.5 mm). All methods resulted in DNA suitable for downstream applications and were successfully amplified. Overall, the Qiagen Puregene Tissue kit yielded relatively high DNA concentrations for most sizes and amounts of plastics at relatively low costs and short processing time. This study provides a detailed evaluation of DNA extraction methods from ocean plastics, and may assist future research using molecular techniques to study ocean plastic biofilms.

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• The Effect of Particle Properties on the Depth Profile of Buoyant Plastics in the Ocean

  Article in peer-reviewed journal
  October 2016, Scientific Reports 6, Article number: 33882

  Merel Kooi, Julia Reisser, Boyan Slat, Francesco F. Ferrari, Moritz S. Schmid, Serena Cunsolo, Roberto Brambini, Kimberly Noble, Lys-Anne Sirks, Theo E. W. Linders, Rosanna I. Schoeneich-Argent and Albert A. Koelmans

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  • Publication type: Article in peer-reviewed journal
  • Journal: Scientific Reports 6, Article number: 33882 (2016)
  • Collaborators: Wageningen University & Research (The Netherlands), Université Laval (Canada), Aalborg University (Denmark), Roger Williams University (USA), CABI Europe-Switzerland (Switzerland), University Oldenburg (Germany), IMARES - Institute of Marine Resources & Ecosystem Studies (The Netherlands)
  • DOI: 10.1038/srep33882
  • Submitted: 13.06.2016
  • Accepted: 05.09.2016
  • Published: 10.10.2016

  Abstract

  Most studies on buoyant microplastics in the marine environment rely on sea surface sampling. Consequently, microplastic amounts can be underestimated, as turbulence leads to vertical mixing. Models that correct for vertical mixing are based on limited data. In this study we report measurements of the depth profile of buoyant microplastics in the North Atlantic subtropical gyre, from 0 to 5 m depth. Microplastics were separated into size classes (0.5–1.5 and 1.5–5.0 mm) and types (‘fragments’ and ‘lines’), and associated with a sea state. Microplastic concentrations decreased exponentially with depth, with both sea state and particle properties affecting the steepness of the decrease. Concentrations approached zero within 5 m depth, indicating that most buoyant microplastics are present on or near the surface. Plastic rise velocities were also measured, and were found to differ significantly for different sizes and shapes. Our results suggest that (1) surface samplers such as manta trawls underestimate total buoyant microplastic amounts by a factor of 1.04–30.0 and (2) estimations of depth-integrated buoyant plastic concentrations should be done across different particle sizes and types. Our findings can assist with improving buoyant ocean plastic vertical mixing models, mass balance exercises, impact assessments and mitigation strategies.

  • Hydrology, Marine biology, Marine chemistry, Physical oceanography

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• The Vertical Distribution of Buoyant Plastics at Sea

  Article in peer-reviewed journal
  February 2015, Biogeosciences 12

  Julia Reisser, Boyan Slat, Kim Noble, K. du Plessis, Meredith Epp, Maira Proietti, Jan de Sonneville, Thomas Becker and Charitha Pattiaratchi

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  • Publication type: Article in peer-reviewed journal
  • Journal: Biogeosciences 12, 1249-1256 (2015)
  • Collaborators: University of Western Australia (Australia), Roger Williams University (USA), Pangaea Exploration (USA), Universidade Federal do Rio Grande (Brazil)
  • DOI: 10.5194/bg-12-1249-2015
  • Submitted: 31.10.2014
  • Accepted: 16.02.2015
  • Published: 26.02.2015

  Abstract

  Millimetre-sized plastics are numerically abundant and widespread across the world’s ocean surface. These buoyant macroscopic particles can be mixed within the upper water column by turbulent transport. Models indicate that the largest decrease in their concentration occurs within the first few metres of water, where in situ observations are very scarce. In order to investigate the depth profile and physical properties of buoyant plastic debris, we used a new type of multi-level trawl at 12 sites within the North Atlantic subtropical gyre to sample from the air–seawater interface to a depth of 5 m, at 0.5 m intervals. Our results show that plastic concentrations drop exponentially with water depth, and decay rates decrease with increasing Beaufort number. Furthermore, smaller pieces presented lower rise velocities and were more susceptible to vertical transport. This resulted in higher depth decays of plastic mass concentration (milligrams m−3 ) than numerical concentration (pieces m−3 ). Further multilevel sampling of plastics will improve our ability to predict at-sea plastic load, size distribution, drifting pattern, and impact on marine species and habitats.

  • Marine debris, Vertical distribution

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• How the oceans can clean themselves: a feasibility study

  Independently published book
  June 2014, The Ocean Cleanup

  Boyan Slat et al.

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  • Publication type: Independently published book
  • Published: June 2014

  Abstract

  The research described in this feasibility report indicates that The Ocean Cleanup Array is a feasible and viable method to remove large amounts of plastic pollution from a major accumulation zone known as the Great Pacific Garbage Patch. Computer simulations have shown that floating barriers are suitable to capture and concentrate floating plastic debris. Combined with ocean current models to determine how much plastic would encounter the structure, a cleanup efficiency of 42% of all plastic within the North Pacific gyre can be achieved in ten years using a 100 km Array. In collaboration with offshore experts, it has been determined that this Array can be made and installed using current materials and technologies. The estimated costs are €317 million in total, or €31.7 million per year when depreciated over ten years, which translates to €4.53 per kilogram of collected ocean debris.

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