Almost all coral reefs, including very deep and remote reefs, are polluted with plastic waste, according to a new study published in the journal Nature. After surveying 84 reefs around the world at varying depths, a team of researchers found that plastic makes up 88 percent of the debris in coral reefs — and 73 percent of that plastic is fishing gear.
“The biggest thing we found is that there is more litter on deeper reefs,” said Lucy Woodall, co-author of the study and associate professor at the University of Exeter. “We have had good information for many years from lots of groups doing good work in shallow water coral reefs, but now that we extended operations into deeper waters, we can see the litter extends into deeper reefs.”
Surprising findings about the state of plastic in coral reefs
While the results are alarming, Woodall, who is also a marine conservation scientist at the ocean research nonprofit Nekton, insists the paper contains good news. “This is a positive story and one that enables us to think about what our future decisions might be," she said. "When there is protection afforded to marine areas, minimal litter items are found.”
The pollution that was found in protected areas was light plastic that floated into the area from far away. Ocean states face a disproportionate impact of litter entering their boundaries from other places and will need global support to address the pollution. “It’s like climate change,” Woodall said.“The biggest emitters aren’t the ones living with the everyday experiences of a warming planet.”
Some reefs close to human populations have higher levels of plastic pollution, but another hotspot for reef pollution was reefs just outside of marine protected areas, according to the study.
When it comes to these hotspots, “We know that we have an association, but we don’t know why,” Woodall said. “It could be from recreational uses because people like to swim in those areas. This could be people that are using resources and services that marine protected areas provide. Perhaps it is fishers looking for a spillover effect. We found that there is a correlation with areas that don’t have a robust, fully-connected infrastructure that allows for careful waste management.”
Understanding the data helps us create better solutions, Woodall said. For example, if more studies show high levels of reef pollution in areas just outside of marine protected areas, policymakers could use that knowledge to create additional boundaries around these areas to act as buffers. “If we know some of these details, it helps make decisions. We can find opportunities when things feel scary,” she said.
Understanding the solutions at hand
The solution to protecting coral reefs is not as simple as an ocean clean-up. While it might seem easy to pick up something from a beach or river mouth, cleaning up coral reefs is not only logistically challenging but can actually damage ecosystems.
“Clean-ups can be brilliant because they get communities engaged in their local environments and can provide educational components,” Woodall said. “However, it is flawed thinking that clean-ups will be successful by themselves. We need to turn off the tap and stop litter from coming into the oceans.”
Plastic pollution comes from sources on land and at sea. For pollution that comes from land, policymakers must take a holistic view of the challenges in order to provide opportunities for change, Woodall said. Plastic debris across the world looks different depending on the area, and solutions should take into account local circumstances and constraints.
“Think about potable water,” she said. “If you can provide clean fresh water to a location, then the community doesn't have to buy it. It is better for the plastic pollution problem, but it also gives the community a social and economic benefit. We should couple benefits and solutions together. Often, we can reduce plastic waste by doing something positive that communities will benefit from.”
Stemming the tide of plastic from boats
Waste that comes from ocean vessels is different. While the research team for this study did not test this theory, one hypothesis is that plastic waste generated from vessels in the ocean comes from two sources — waste that’s dropped over the side of boats while they are at sea and lost fishing gear.
There are already many regulations around the world that make it illegal to dump waste into the oceans, but it is still happening, possibly due to a lack of waste infrastructure on shore. “If there is no formal waste management in port, and you have to drop it by the side of the ocean anyway, there may not be the motivation there to not drop it directly into the ocean,” Woodall said.
Plastic pollution from fishing gear is a different scenario. “No fisher wants to discard their means of income on purpose. They need that for financial and food security,” Woodall said. Broken gear is often discarded at sea, likely because there are no waste facilities ashore, but fishing gear is also lost unintentionally. Fishing gear can get stuck on ragged coral reefs, for example, which is a big problem for marine life that gets entangled and stuck in lost nets and lines.
To address these problems, some countries have implemented programs in partnership with Fishing for Litter, which encourage fishers who accidentally bring up old gear in their nets to bring it back to shore and dispose of it. Additionally, with proper waste infrastructure in place, practices like labeling fishing gear could be enforced to ensure that fishers take responsibility for their equipment, Woodall added.
Local solutions for a global problem
Although the new study did not investigate every reef in the world, the data came from diverse locations and depths to help researchers understand global patterns. When it comes to solutions to the global plastic problem, “Solutions need to happen locally,” Woodall said.
“We must listen to our local communities and Indigenous communities and people whose heritage and culture are integrated into the places where they live, because they will often give important insight on how to make changes," she said. "We need to ask communities what they need to make change. Let’s ask the right questions and listen to the people with solutions.”
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