Marine Litter Vital Graphics

CONCLUSIONS

Plastic debris and microplastics are by far the main components of marine litter and are omnipresent in the world’s oceans – from remote shorelines to the deep ocean, from the poles to the equator. The quantity of plastic observed in coastal waters off densely populated regions and in the mid-ocean gyres, despite high concentrations, represents only a fraction of the total amount in the marine environment. In addition, many types of plastic waste are denser than water and will sink to the sea floor. Surface accumulations in mid-ocean subtropical gyres are just the tip of the iceberg. While uncertainties remain, it is estimated that open ocean floating plastic accounts for less than 1 per cent of the total that has reached the oceans since it began to be produced. Conclusions

Production of single-use, throw-away plastic products has increased exponentially since the 1950s. At the same time, plastics are designed to be durable and it is precisely this characteristic, combined with an unwillingness or inability to manage waste effectively, that has created a global issue. It is a complex social, economic and environmental problem which knows no boundaries. It threatens entire marine ecosystems, has enormous economic consequences and affects the livelihoods of millions of people. The cause is human activity – on the land and in the seas. All sectors and individuals contribute to this pollution – from poorly controlled waste sites, illegal dumping and mishandled waste on land to floating ropes, nets, floats and other debris from fishing, merchant shipping, oil rigs, cruise ships and other sources. Larger “macroplastics” harm marine life when animals and fish become entangled or eat them. However, more research is needed to determine impacts on population levels which can further affect endangered species, sensitive habitats and ecosystems. All of these have tangible and measurable socioeconomic consequences for fisheries, shipping and tourism. Out of sight but not out of mind Microplastics measure less than 5 mm in diameter and are either manufactured for industrial or domestic purposes

(“primary” microplastics such as microbeads in toothpaste) or are a result of weathering and fragmentation of larger material (“secondary” microplastics). Weathering and fragmentation is assisted by exposure to UV radiation and oxygen at or close to the water surface. However, at lower levels the lack of light slows this process so that it takes a long time for even “biodegradable” plastics to break down. There is a major gap in our knowledge about the actual quantities of plastic debris and microplastics and the proportion coming from from different sources. A further challenge is that we cannot see a large part of the litter because it lies below the surface. Even more worryingly, we don’t know whether it is affecting the trophic chain; the potential for bioaccumulation in certain species; what chemicals are released into themarine environment when plastic waste degrades; the impact on food safety or the potential connections to climate change. The fact that so much is out of sight explains why there are no reliable estimates of the total quantity of plastic in the ocean and why research on its effects on marine life and human consumption is still in its infancy. However, there is sufficient evidence that marine plastics and microplastics are having an unacceptable effect. Immediate action based on available knowledge needs to go hand in hand with improved and adaptive management and governance approaches that will evolve as more is learned.

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Marine Litter Vital Graphics