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Jun 22nd 2020

Marine Life Is Harmed by Plastic Pollution That Smells Like Food

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The impact of discarded plastic waste threatens our natural world. From the sacred Ganges River to the pristine Arctic Ocean, marine life is in danger from physical entanglement, starvation and poisoning, simply by mistaking floating plastics as food.

Until recently, scientists thought sea life ate plastics because the floating debris looks a lot like food; a hungry sea turtle could easily mistake a plastic bag for a jellyfish. But a paper published in the Proceedings of the Royal Society shows that plastic pollution in the ocean also smells like food.

Why Is There a Plastic Buffet in Our Oceans?

The International Union for Conservation of Nature (IUCN) notes that of the 300 million tons of plastic produced every year, around 8 million tons end up in the ocean. Some of this is accidental from container shipping accidents, but most comes from land-based disposal. Inadequate waste handling — from storm or sewage outflow to beach littering and industrial output — means that our discarded plastics contribute around 80% of all ocean debris. Marine life then comes into contact with plastics at all levels; from surface layers to deep sea sediment, there’s no escape.

Furthermore, as plastic debris floats along the ocean surface, it’s bombarded by UV energy. This makes it brittle so that wind and wave action break it down into smaller and smaller pieces. Of the 5 trillion or so pieces of plastic floating around, most are less than 10 mm (less than half an inch) in length.

Bits of Plastic Smell Yummy to an Anchovy

Microplastics and larger debris have been found in all sorts of ocean life, from zooplankton and krill to the bellies of fish and whales. Apart from mistaking shreds of plastic as food, the pollutants may also smell delicious to sea creatures.

When plastic breaks down in the ocean, it’s coated by algae, which makes it smell like food. Researchers found that when presented with biofouled plastic debris, shoals of anchovies displayed the same foraging behavior as they did when presented with a buffet of krill. The scientists concluded that the food-like smell might be another reason marine life nibbles on plastic.

Once consumed, the plastic “food” is incredibly harmful. Not only does it crowd out real food in the gut and starve the animal, it also releases biotoxins that poison the host, reducing fertility and adversely changing behavior. However, it doesn’t only affect the marine life; it rises higher up through the food chain all the way to us.

What Can We Do?

Plastics were originally developed to replace natural materials. The Smithsonian notes that this included creating a synthetic substitute to replace elephant ivory in billiard balls. However, the Center for Biological Diversity predicts that by 2050, there will be more plastics in the sea than fish. It’s important to act now to prevent this.

Reducing waste by replacing single use plastic items with reusable ones could impact plastic pollution in the ocean. As Vox notes, “plastic bans are in vogue;” many countries have started initiatives to reduce plastic straws and shopping bags. Countries have also banned plastic microbeads from personal care products. Outreach programs, such as the Plastic Seas initiative from Earth Ocean, spread awareness by bringing the problem into classrooms.

Stopping waste from reaching the ocean is one strategy but what about removing the plastic that’s already there? The Ocean Cleanup project uses passive boom systems to concentrate waste in ocean gyres for more efficient removal. The organization also has an interceptor solution that stops plastics in rivers from reaching the oceans in the first place.

Another removal strategy uses carbon nanosprings that accelerate microplastic breakdown. University of Adelaide researchers created the magnetic coils that generate reactive oxygen species to break down microplastics so they dissolve quickly in wastewater before reaching the sea. Being magnetic, the nanosprings can also be removed easily for repeated use.

Other tactics focus on changing how plastics are made. Scientific American describes how changing the formulation could create fully recyclable plastic that can be reused over and over again in manufacturing. It might also give us a biodegradable plastic that breaks down fully in water to avoid becoming part of the marine buffet.

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