Scientists in the U.S. believe they have found out why some seabirds are attracted to eating waste plastic floating in the world's oceans: It smells good.
A study published in Science Advances found that plastic debris "emits the scent of a marine infochemical, creating an olfactory trap for susceptible marine wildlife."
Using mesh bags tethered in various parts of the sea off the west coast of the U.S. containing low density polyethylene, high density PE and polypropylene beads, researchers found that three types of plastic acquired a particular signature smell.
The odor, which some seabirds find irresistible, came from diamethyl sulphide (DMS), which smells like decaying seaweed.
DMS also results when plankton, which collects on waste plastic objects, breaks down.
"These seabirds actually use odors to find their way around in the world and to find food," Matthew Savoca, of the University of California, Davis, told the BBC.
"We found a chemical on plastic that these birds typically associate with food, but now it's being associated with plastic.
"And so these birds might be very confused – and tricked into consuming plastic as food."