Why Plastic in Ocean Looks So Tempting to Seabirds

Why Plastic in Ocean Looks So Tempting to Seabirds

A new study suggests that a certain chemical compound in plastic debris adrift in the ocean may make the material seem as tasty as real food to hungry seabirds. Researchers believe plastic releases special odors that make seabirds end up snacking on it.

Humanity dumps more than 10 million of plastic in the ocean every year. Surprisingly, 90 percent of seabirds feast on it. So, scientists have scratched their heads due to the phenomenon for years. They kept wondering what made plastic so appealing to these animals.

Lead author Matthew Savoca believes that the new findings could help humans produce less tasty plastic and save seabirds from demise. Savoca explained that many animals apparently do ‘stupid’ things, but from those animals’ perspective, their actions make a lot of sense.

And that is the case with seabirds too. The chemicals in plastic act like a cue for them to find food. So, their decision to eat it is not stupid or crazy, but ‘very precise,’ Savoca thinks.

The researcher acknowledged that the very ‘craziness’ of the idea convinced him to start an analysis of the issue. And the findings were surprising. The team found that petrels, albatrosses, and shearwaters are especially attracted to plastic because it smells like rotting seaweed.

Researchers found that a compound in plastic called dimethyl sulfide (DMS) is released by algae when krill and other small animals on the birds’ menu feast on them. So, if these seabirds, which have a good sense of smell, detect DMS signals they’ll think it is food.

Plus, if the decaying plants wrap around plastic debris, the DMS signals are all the more hard to resist. Savoca noted that another fact confirmed his team’s findings. The species of seabirds that depend on smell to find food eat more plastic than other bird species.

Experts who commented on the findings said that the discovery could finally explain why we find so much plastic in seabirds’ guts. Conservationists find dozens of seabirds literally stuffed with plastic bits every day.

Dead albatross chick

Carcass of albatross chick with stomach full of plastic waste.

So, eating trash may not be just a whim after all. Past theories suggested that the birds munch on plastic simply because it visually resembles food. For instance, many sea turtles gorge on plastic bags probably because they think it is jellyfish.

However, the latest study suggests that it takes more than one sense to convince someone to eat something. For example, Savoca added, pizza wouldn’t be as appealing if it weren’t for both looks and smell. Birds just like humans, apparently need more cues to confirm that a piece of something is good to eat.

Researchers declined to confirm whether plastic trash kills seabirds and other marine creatures. But biologists are convinced that just carrying deadweight in their stomachs may be detrimental to birds. Plus, plastic gives birds no energy. Instead, they spend precious energy in trying to digest plastic. And that waste of energy is crucial to animals that need to be as light as possible to survive.

The study was published Oct. 9 in the journal Science Advances.

Image Source: Wikimedia