Plastic pollution is a growing crisis in the earth's oceans for many reasons.
One of the lesser understood implications, however, is its impact on seabirds who often mistake plastic debris for food.
A recent study by researchers at the University of California-Davis found that the problem isn't as simple as birds becoming confused. Instead, their analysis found that plastic in the ocean gives off the same scent that triggered those birds' hunting instincts for millions of years.
In the study, published in the journal Science Advances, scientists placed beads comprised of common plastic pollutants — high- and low-density polyethylene and polypropylene — into the ocean off the California coast and collected them three weeks later.
The university's Department of Viticulture and Enology — which ordinarily studies grapes and wine — then analyzed the beads and found the smell of dimethyl sulfide, or DMS, a sulfur compound also released when algae are eaten by krill — a staple food source for some seabirds.
Scientists said that seabirds that track DMS to find food are nearly six times more likely to eat plastic than other seabirds. Tubenosed seabirds such as the petrel and albatross, who hunt using their keen senses of smell, are particularly vulnerable.
"Animals usually have a reason for the decisions they make," said UC-Davis graduate student Matthew Savoca.