Marine plastic debris is an olfactory trap for seabirds

https://www.eurekalert.org/pub_releases/2016-11/uoc--wds110316.php

Public Release: 9-Nov-2016
Why do seabirds eat plastic? The answer stinks
Marine plastic debris is an olfactory trap for seabirds
University of California - Davis

If it smells like food, and looks like food, it must be food, right?

Not in the case of ocean-faring birds that are sometimes found with bellies full of plastic. But very little research examines why birds make the mistake of eating plastic in the first place.

It turns out that marine plastic debris emits the scent of a sulfurous compound that some seabirds have relied upon for thousands of years to tell them where to find food, according to a study from the University of California, Davis. This olfactory cue essentially tricks the birds into confusing marine plastic with food.

The study, published Nov. 9 in the journal Science Advances, helps explain why plastic ingestion is more prevalent in some seabird species than in others. Tubenosed seabirds, such as petrels and albatross, have a keen sense of smell, which they use to hunt. They are also among the birds most severely affected by plastic consumption.

•••••

Using food-and-wine chemist Susan Ebeler's chemical analyzer, the team confirmed that, sure enough, the plastic reeked of the sulfur compound dimethyl sulfide, or DMS, a chemical cue released by algae, which coats floating plastic.

Co-author Nevitt, with the UC Davis Department of Neurobiology, Physiology and Behavior, had previously established that DMS is a scent that triggers tubenosed seabirds to forage. DMS is released when algae is eaten by animals like krill, one of the birds' favorite meals. So while the algae does not smell like food itself, it does smell like food being eaten, which is the birds' version of a dinner bell.

The study noted that seabirds that track the scent of DMS to find prey are nearly six times more likely to eat plastic than those that do not.

•••••