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If you look closely, you can just make out the words “Philip Morris International.” The tobacco company's name can be seen on the translucent strip of a cigarette box wrapper that was photographed inside a mauve stinger jellyfish found swimming through the Mediterranean Sea.
Animals trying to avoid ocean plastic have to navigate a minefield. Eighteen billion pounds of it flows into the ocean every year, making it difficult for animals, like jellyfish, to avoid.
Last April, a study published in the journal Scientific Reports published the first documentation of plastic in a jellyfish.
The jelly was found in the Mediterranean Ocean in 2016 by a group of scientists participating in the Aquatilis Expedition, a three-year research trip to explore the world's oceans. In their study, the researchers say multiple mauve stingers had various types of plastic trash trapped under their hoods or woven through their bodies.
When twenty were netted and inspected more closely, four stingers were found with plastic in their digestive system, leading the scientists to believe the jellyfish had mistaken the plastic for food.
“They are really in love with plastic, it seems,” says one of the study's authors, Armando Macali, an ecologist from Tuscia University in Italy. He says he and his fellow study authors are strongly convinced the jelly was holding on to the plastic because it was trying to eat it.
Past studies have shown that marine animals accidentally consuming plastic debris is a widespread problem. Scientists think animals consume it because it resembles their prey: turtles eat jellyfish-like plastic bags, and fish eat small rice-sized plastic that resembles their normal food.
Ocean plastic also smells appetizing to some marine critters. In 2016, a study in the journal Science Advances found that algae easily grows on ocean plastic, and as it breaks down, it emits an odor called dimethyl sulfide that attracts hungry animals.
It's not clear why the jellyfish was attracted to the plastic, says Macali. After plastic trash enters the ocean, it begins to weather, and thin layers of biofilm coat it. Macali suspects either the biofilm or some molecule in the breaking down plastic attracted the jellies.
In future experiments, he plans to expose jellyfish to various types of plastic debris in lab conditions. If scientists are able to identify specifically what's attracting the animals, he says, they could potentially work with manufacturers to make plastic that's less attractive to marine organisms.
That the mauve stinger was trying to eat the plastic wrapper is a bad sign for the animal's health, the scientists note. Mauve stingers can consumer 50 percent of their body weight, and ingesting too much plastic has been shown to cause animals to slowly starve.
As a prey species for other, larger animals in the Mediterranean, plastic-laden jellyfish could have similarly dangerous health impacts on the animals that consume them. Bluefin tuna, one of the mauve stinger's most abundant predators, is commonly caught and eaten by people and marine mammals, meaning the small microscopic pieces of plastic jellyfish consume may end up in the bellies of larger species, including us.
It's a complicated problem, of which researchers are still trying to grasp the scale, says Macali. Understanding how jellyfish interact with ocean plastic will be one piece of a larger puzzle, he adds.
“If we want to understand the fate of plastic in the ocean, we have to start at the bottom of the food chain.”
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