by Dharna Noor
There have been more than enough horrific viral videos of the turtles with straws stuck in their noses to show that plastic is a threat to them (I’ll spare you by not linking them). Studies have found that every minute, the equivalent of one dump truckload of plastic gets into the ocean, and researchers estimate every species of sea turtles in the world is full of microplastic. Eating all that plastic is often fatal.
Scientists have long thought that sea turtles eat plastic because it looks like their prey—plastic bags, for instance, resemble jellyfish. But sea turtles’ attraction to plastic may have more to do with smell than sight, according to a new study.
“This ‘olfactory trap’ might help explain why sea turtles ingest and become entangled in plastic so frequently,” says Joseph Pfaller, a biologist from the University of Florida who worked on the study, in a statement.
To be clear, the turtles weren’t tempted by plastic because it carried the odors of the human food it was wrapped around. Rather, turtles seem to be seduced by the smell of “biofouled” plastic, or plastic covered in microbes, algae, plants, and small animals on wet surfaces. That’s what happens to plastics that end up in waterways.
Pfaller and his co-authors examined 15 young loggerhead turtles’ reactions to smells sprayed through a pipe in a study released on Monday in Cell. They exposed each turtle to four odors: turtle food containing fish and shrimp meal, “biofouled” plastic that mimicked how it smelled in the ocean, and two controls: deionized water and clean plastic. They found that the turtles responded to the smells of biofouled plastic and turtle food in much the same way. In other words, it seems like turtles think plastic in the ocean smells like a tasty treat.