(CN) – As plastic pollution in the world’s oceans continues to increase, scientists revealed in research Monday that the danger is increased for turtles because they often mistake plastic for food.
“We found that loggerhead sea turtles respond to odors from biofouled plastics in the same way they respond to food odorants, suggesting that turtles may be attracted to plastic debris not only by the way it looks, but by the way it smells,” said Joseph Pfaller of the University of Florida, Gainesville.
He added, “This ‘olfactory trap’ might help explain why sea turtles ingest and become entangled in plastic so frequently.”
In a study published Monday in the journal Current Biology, Pfaller and colleagues explained how the accumulation of algae, plants, microbes and small animals on plastic create a smell that attracts sea turtles.
Scientists have long theorized that sea turtles mistake plastics as prey, but the results of the new study show how that is possible with the odor those plastics carry.
To set up their experiment, the researchers used 15 captive-reared loggerhead turtles and exposed them to airborne odorants, including clean plastic and deionized water as well as biofouled plastic and fish and shrimp meal.
Recording the reactions of the turtles, the scientists discovered the sea turtles had the same reaction to the scent of biofouled plastic as they did their traditional food sources.
“We were surprised that turtles responded to odors from biofouled plastic with the same intensity as their food,” Pfaller said. “We expected them to respond to both to a greater extent than the control treatments, but the turtles know the smell of their food since they’ve been smelling and eating it in captivity for five months. I expected their responses to food to be stronger.”
Pfaller said that, while more research is needed to determine which chemicals in the plastics attracted the turtles, the results of this study clearly shows just how dangerous plastics are to sea life.
“The plastic problem in the ocean is more complex than plastic bags that look like jellyfish or the errant straw stuck in a turtle’s nose,” Pfaller said. “These are important and troubling pieces to the puzzle, and all plastics pose dangers to turtles.”