Plastic pollution in oceans, also known as marine debris, is a growing problem at local and global scales. Anthropogenic marine debris poses a serious threat to many marine species, both through physical harm such as ingestion or entanglement and by carrying toxins and pathogens. This debris accumulates in oceanic gyres, concentrating these effects in some specific areas. In addition, marine debris may have devastating impacts on tourism and fishing-based economies, especially where ocean currents direct this debris. Recently, a nonprofit organization called The Ocean Cleanup proposed the first large-scale in situ marine debris removal project. The Ocean Cleanup is a project attempting to use large, floating, semi-fixed screens to harness ocean currents and accumulate debris, where it can be efficiently collected and disposed of or recycled. The project currently is working on implementing itself in the “Great Pacific Garbage Patch,” in the North Pacific Gyre. We examine this project case, as it is the first organization attempting to clean up marine debris at this scale. Understanding the potential efficacy and limitations of The Ocean Cleanup Project as a case study can give critical insights into how other projects could be created in the future to address marine plastic pollution worldwide. Using SWOT (strengths, weaknesses, opportunities, and threats) analysis to assess a marine debris cleanup can inform both a nuanced evaluation of the specific case as well as provide a means to explore marine debris as a complex, global environmental problem.

INTRODUCTION

Plastic pollution in oceans, also known as marine debris, is a growing problem at local and global scales. In 2009, the United Nations Environment Program identified marine debris as a major problem [1]. Our case study first addresses how plastic ends up in the ocean as debris, the impacts of marine plastic debris on wildlife of conservation concern, and the economic and human health impacts of marine plastic. Then, we focus on the North Pacific Gyre and the “Great Garbage Patch” — and specifically a recent initiative to develop cleanup technologies of marine plastic in this gyre, led by The Ocean Cleanup. Understanding the potential efficacy and limitations of The Ocean Cleanup Project as a case study can give critical insights into how other projects could be created in the future to address marine plastic pollution worldwide.

Marine Debris Accumulation

Marine debris enters the ocean through a variety of sources, both accidental and intentional, such as littering, river and storm runoff, lost or derelict fishing equipment, and offshore garbage dumping. A variety of materials comprise this debris, including styrofoam, plastics, metal, and wood. Wind and marine currents can help to scatter this debris throughout the ocean, but their overall effects tend, on average, to drive debris toward the centers of oceanic gyres [2]. In these gyres, marine debris can form large patches that float at the surface of the water column, which can cover thousands of square miles and contain approximately 334,271 pieces of plastic per square kilometer [3]. One of the concerns of these collections of marine debris is that it contains or is composed of harmful chemicals that can leach into seawater. Many of the common pollutants found in the “Great Garbage Patch” in the North Pacific Gyre include carcinogens, pesticides, heavy metals, and endocrine disruptors, and the concentrations of some of these pollutants can exceed a 1,000 parts per billion, extremely high for seawater [3]. This may be worsened by the tendency of some plastics to accumulate some types of toxins that they encounter while drifting, which may then increase the concentrations of these toxins where plastics accumulate [3].

SWOT Analysis

SWOT analysis is a strategic planning technique for projects and institutions. SWOT analysis stands for strengths, weaknesses, opportunities, and threats analysis. Strengths are defined as characteristics that give the project or organization competitive advantage; weaknesses are defined as characteristics that give it a disadvantage (as reviewed by Guerel [4]). Opportunities and threats are defined as external factors, outside the project or organization that may be beneficial or harmful (as reviewed by Guerel [4]). SWOT analysis was developed for business management and is now used in environmental science project management and planning. SWOT analysis was popularized by Albert Humphrey and the Stanford Research Institute using business data for management planning in the 1960s [5]. It is now widely used in many fields, including environmental planning and conservation. Specifically, SWOT analysis has been applied in several marine conservation planning contexts, including marine protected area assessment [6] and marine biodiversity monitoring [7]. Using SWOT analysis to assess a paradigmatic case in marine debris cleanup can inform both a nuanced evaluation of the specific case as well as provide a means to explore marine debris as a complex, global environmental problem.

CASE EXAMINATION

Cleaning up plastic pollution is a critical issue in marine ecosystems, as evidenced by all the known effects of marine plastics on wildlife and human communities. Cleanup efforts exist at multiple time and spatial scales. For example, beach cleanups to remove debris and recycling campaigns to prevent debris from entering oceans have taken place for decades and are generally organized at local and regional scales. Recently, a nonprofit organization called The Ocean Cleanup proposed the first large-scale in situ marine debris removal project, working in the North Pacific Gyre.

The Ocean Cleanup was founded by Boyan Slat in 2013 with the goal of designing and deploying methods to rid the oceans of marine debris. There are several strengths and weaknesses of The Ocean Cleanup — and several opportunities for and threats to its success. Critically evaluating The Ocean Cleanup proposed techniques and timelines is important for supporting both their goals and the broader goal of successful marine debris removal strategies throughout the world.

Strengths

Strengths are characteristics inherent to The Ocean Cleanup that give it as an organization and initiative a competitive advantage.

The Organization is the First to Attempt Marine Debris Removal at Scale

The Ocean Cleanup proposed the first large-scale in situ marine debris removal project, working in the North Pacific Gyre. Specifically, the organization has the ambitious goal of cleaning at least half of the plastics floating in the North Pacific Gyre in a matter of 5 years. The Ocean Cleanup is the first organization attempting to clean up marine debris at this scale. The North Pacific Gyre is the largest accumulation of floating trash in the world, with an estimated 1.8 trillion pieces of plastic according to surveying done by The Ocean Cleanup scientists [8]. To achieve this hefty goal, Boyan Slat and his team of scientists and engineers have designed a U-shaped collection system that will free-float in the gyre to collect floating plastics. The collection system will utilize the forces of the oceanic gyres to direct debris into a barrier.

The Organization has Learned from Previous Unsuccessful Deployments

The Ocean Cleanup’s unsuccessful launch was predated by technical difficulties with prototypes. The organization’s own 2014 feasibility study greatly underestimated ocean forces that deployed technology would have to withstand [9]. Prototypes thus failed. The first, a design based off of conventional oil containment booms, did not last at sea for an extended period of time. Another prototype made of high-density polyethylene (HDPE) pipes was able to withstand the ocean; however, the screening material used to capture debris was faulty and ripped apart. Yet, the organization continued tweaking their approach. The first full-scale launch proceeded only after 273 scale model tests, six in situ prototypes, extensive mapping of the gyre, and additional materials testing.

Weaknesses

Weaknesses are characteristics inherent to The Ocean Cleanup that give it as an organization and initiative a competitive disadvantage.

The First Full-Scale Deployment was not Successful

The Ocean Cleanup launched its first full-scale system deployment on September 8, 2018, from the Alameda Naval Air Station in San Francisco Bay Area, California, where the “System 001” then towed out to the Pacific Ocean after 2 weeks [10]. The long-term goal is to have at least 50 of these 600-m long, 3-ft-deep systems working in the Pacific Ocean at once with large support vessels returning approximately every 6 weeks to extract the debris. Yet, by December 29, 2018, the system was not fully functioning, and debris was not successfully remaining contained by the boom. By December 31, the launch was ended and System 001 brought back to harbor for further testing to prevent debris from accumulating on wrong side of the barrier.

It is Unclear how Full-Scale Deployment will Impact Marine Wildlife

There are many remaining uncertainties about how The Ocean Cleanup technology will impact marine wildlife, due to the size of the equipment and compounded by a lack of data on specifically which taxa inhabit the North Pacific Gyre. In a survey of marine biology experts, 50% of respondents reported major concern of marine entanglement and death [11]. The Ocean Cleanup refutes the findings and claims of the survey. Since The Ocean Cleanup’s first launch, concerns have been raised in particular about the neuston [12]. Neuston are organisms that live on the surface of the ocean; they can also act as ecosystems onto themselves, serving as a nursery for larval fish. The concern is that The Ocean Cleanup’s unique approach to containment and removal of marine debris may also remove surface-living and free-floating organisms and “islands” like neuston. It is not yet clear whether the array will capture animals or whether they will be able to escape. The Ocean Cleanup response is that models indicate the majority of gyre objects are large, so they anticipate impacts on small organisms to be minimal.

The Ocean Cleanup does not Reduce the Overall Production or Consumption of Plastics

The point of intervention is postconsumer, and thus it is not a prevention-oriented project. Alternative approaches to marine debris, such as the 5 Gyre Institute efforts, focus on promoting the end of plastic use or collecting plastics in streams and rivers before plastics are released into the oceans. Single-use plastics such as cutlery, straws, and plastic bags are a few items that, if discontinued or at the very least used minimally, would help to reduce a significant amount of plastics that reach the oceans. Although existing plastic debris in the ocean should not be ignored and must be addressed, The Ocean Cleanup is not the only approach and alternatives should be discussed when considering its strengths and limitations.

Opportunities

Opportunities are factors external to The Ocean Cleanup and its approach that may be beneficial to its success.

There is a Growing Global Need to Address the Harm Marine Debris Causes to Wildlife

Marine plastics can harm marine wildlife through several direct and indirect pathways. A major cause of harm is through wildlife eating plastics. Fish, sea turtles, and seabirds are all frequently cited as ingesting large amounts of marine debris, either directly or due to their prey first consuming the debris [1315]. Many plastics cause lacerations and blockage of digestive tracts. In some cases, eating plastic can result in starvation of organisms. Sea turtles, most species of which are endangered, are especially impacted by this [15, 16]. Wildlife can also be harmed if their prey eat plastics. Seabirds are also shown to suffer from digestive issues due to marine debris in their gastrointestinal tract, generally acquired through consumption of fish which have previously consumed marine debris [17].

Marine debris can also cause significant harm to individuals and food webs through indirect pathways. Bioaccumulation of both plastics and pollutants from plastics are emerging threats that can cause sublethal harm. Micropollutants such as polychlorinated biphenyl (PCB), polycyclic aromatic hydrocarbons (PAHs), and dichlorodiphenyltrichloroethane (DDT) concentrations in the North Pacific Gyre range from 1 to 10,000 ng/g [18]. Bioaccumulation can cause mortality in apex predators, which are often keystone species and have longer reproductive cycles, limiting their ability to adapt to and recover from this sort of threats. Plastics can also harm wildlife through entanglement. For larger organisms, such as cetaceans and pinnipeds, entanglement in marine debris such as ghost fishing nets may cause drowning or cause difficulty swimming and foraging [19, 20]. Globally, 200 plus species (115 in the United States) have been impacted by marine entanglement while 26 marine mammal species, one-third seabirds, and sea turtles are shown to have ingested plastics in their life cycle [21].

Marine Debris Cleanup Would Benefit Human Health and Economies

Marine plastic impacts not only wildlife populations but also human communities. Bioaccumulation of plastics in marine food webs has impact beyond mortality or harm to fished species. Some marine species ingesting plastics are consumed by humans, putting people at risk of consuming both marine debris itself and related toxins [1315]. Marine plastic debris not only accumulates in ocean gyres but also washes up on coastal beaches. If marine plastics are left on or move to coastal environments, this will impact coastal economies, not just ecosystems. A survey in California found that 85% of beachgoers would change beachgoing locations based on the presence and amount of plastic waste [22]. Marine plastic pollution is estimated to cost industries globally $13 billion [23].

Citizen Science and Community-Led Initiatives do not Appear to More Efficiently Remove Marine Debris Closer to the Source

Governmental agencies, nongovernmental organizations, and local communities have started marine debris removal initiatives. The Georgia Sea Turtle Center Marine Debris Initiative (GSTC-MDI) is a funded program developed to engage citizens in the removal of marine debris from local beaches. A study of 231 GSTC-MDI volunteers found that they spent 461 h on marine debris removal efforts, collecting a combined total of 6,527 pieces of marine debris [24]. Although the GSTC-MDI effectively cleaned beaches and spread awareness of marine debris problems to its volunteers and other community members, the scale of plastic cleaned up is very small compared to the amount that The Ocean Cleanup hopes to capture in each collection. There is an opportunity for The Ocean Cleanup, if successful, to significantly reduce marine debris at a scale other approaches cannot replicate.

Threats

Threats are factors external to The Ocean Cleanup and its approach that may be harmful to its success.

Other Organizations may Build Better Open Ocean Technology Faster

In 2009, the United Nations Environment Program wrote about the marine debris problem and identified a lack of infrastructure in coastal areas as a major flaw [1]. This has sparked South Korea, for example, to initiate a national project to develop engineering solutions. This project is entitled the “Practical Integrated System for Marine Debris” and incorporates different technologies in an integrated system: prevention, deep-water survey, remove, and recycling. This marine debris removal framework has spearheaded the creation and use of different technologies and infrastructure. Another technology developed was a deep-sea survey system “Tow-Sled,” which is capable of examining benthic derelict fishing gear, and this “Tow-Sled” technology is capable of detecting it with little to no negative impacts. Lastly, once detected, marine debris are difficult to remove. They have developed a removal device aboard a vessel that typically has three main components: An L-type steel pipe assembly device, a streamlined rotating hook, and a hook working on the ship [25]. The Korea Fisheries Infrastructure Promotion Association operates the vessel approximately 140 days per year and collect 350 tons of marine debris annually [26]. The final step in the “Practical Integrated System for Marine Debris” framework is to send the collected marine debris to be recycled or incinerated if not reusable.

Other Organizations are Building Technology to Prevent Debris from Entering the Ocean, Rather than Cleaning Up the Oceans

Over 60% of the floating marine debris entering the oceans originate from human activity on land and flow into the oceans during heavy rainfall events [27]. South Korea engineers developed a floating debris containment boom. It is designed to be buoyant and stable on the upper part and contains a mesh skirt on the lower part to trap all floating debris flowing against it. Floating booms can be an effective preventative strategy in outflows, using containment approaches like The Ocean Cleanup but focused on near- or onshore deployment, where debris is easier to contain and collect.

Other Approaches can more Effectively Track Debris in Real Time

Other projects focus on precision data to track specific debris movements and then only deploy equipment in specific places and for short time periods. An important monitoring technology that can pave the way for marine debris collection methods and enhance the amount of marine debris collected is the use of satellite location tracking buoys. Small buoys with satellite location transmitters have been used in the Nakdong River in South Korea to continuously monitor the movement of marine debris [27]. The use of satellite location tracking buoys allowed researchers to identify sections of the river where an accumulation of marine debris occurred. Once the marine debris accumulation hotspots are identified in a watershed, floating debris containment booms can be implemented during peak flow times. This combination will allow for optimization in the prevention of inland plastic debris from reaching the oceans.

CONCLUSION

Marine debris is a critical global threat that necessitates response to mitigate existing harms to wildlife and human communities. Complex global problems such as plastic pollution necessitate local and worldwide partnerships to work toward the removal of marine debris. The Ocean Cleanup is a leader in this regard — as the first organization to propose and attempt marine debris cleanup in large oceanic gyres. Yet, a common criticism of The Ocean Cleanup and other marine debris removal programs is that these efforts do not reduce the source of plastics and microplastics from entering the world’s oceans in the first place. This is an important concern; however, it is difficult for one initiative or project to solve all the marine debris problems. Instead, The Ocean Cleanup project needs to work hand in hand with other preventative marine debris initiatives to maximize the effectiveness of both. Understanding the strengths, weaknesses, opportunities, and threats of The Ocean Cleanup approach to addressing marine debris in the North Pacific Gyre as a paradigmatic case can inform development of best results for free-floating surface plastic in gyres. In addition, SWOT analysis provides a common framework to compare the approach to alternative approaches, such as coastal containment of plastics.

CASE STUDY QUESTIONS

  1. Do you believe The Ocean Cleanup should perform additional ecological assessments to determine the impact their prototype may have on marine life and ecosystems?

  2. If The Ocean Cleanup prototype negatively impacted a few taxa of macroinvertebrate species in the North Pacific Gyre, should they proceed with the project?

  3. What preventative measures do you think should be put in effect to reduce the amount of plastic debris entering rivers and streams and, subsequently, the world’s oceans?

  4. How do you think local communities would react to floating debris containment booms being used seasonally along coastlines and major river basins?

  5. Do you think local citizen science initiatives are important or helpful given the large scale and issues of marine debris?

  6. Do you think “transboundary issues and shared spaces” issues add to plastic debris problems? How can we incorporate transboundary issues for ocean cleanup?

AUTHOR CONTRIBUTIONS

EM, AS, SS, and ES contributed equally to conceptualization, investigation, and first draft. KW contributed to conceptualization and editing first draft and wrote all revisions.

COMPETING INTERESTS

The authors have declared that no competing interests exist.

We thank one anonymous reviewer and CSE editors for their constructive feedback to improve this manuscript. We also thank the Gosnell School of Life Sciences (GSOLS) Conservation Biology classes of 2018 and 2019 for their classroom testing of and feedback on this case study.

FUNDING

None of the authors were funded for this work.

SUPPORTING INFORMATION

Text S1. Alternative Version: “Evaluating The Ocean Cleanup, a Marine Debris Removal Project in the North Pacific Gyre, Using SWOT Analysis”. Docx.

Text S2. Teaching Notes. Docx.

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