Ocean Plastic Emits Chemical that Tricks Seabirds into Eating Trash

More than 5.3 million tons of plastic waste is dumped into the ocean every year. Some estimates put the amount as high as 12.7 million metric tons. In the article “There’s a StinkyReason Seabirds Eat Plastic” a recent study, published in Science Advances examines the reasons why plastic smells like food to seabirds. "Animals usually have a reason for the decisions they make," says lead author Matthew Savoca, who performed the study as a graduate student at UC Davis. "If we want to truly understand why animals are eating plastic in the ocean, we have to think about how animals find food." In the study they discovered that plastic left in the ocean has a trace of the compound dimethyl sulfide, also known as DMS. Algae that coat the plastic when it sits in the water cause DMS to be released producing a rotten cabbage like odor, which attracts the birds. The birds mistake the plastic for food and ingest it readily.

In the study scientists loaded pellets of three common types of plastic, high-density polyethylene, low-density polyethylene and polypropylene into mesh bags and tied the bags to a buoy in the ocean off the coast of California. After three weeks the bags were collected and a chemical analyzer revealed that the plastic did indeed smell of DMS. The study also explains that species with tubenoses like petrels and albatrosses are more prone to eating plastic than other birds because they follow their noses carefully to find food. This makes them six times more likely to ingest plastic as other birds. A 2015 study estimated that 90% of seabirds eat plastic. This causes damage to their internal organs and can take up valuable space inside their stomach.