While many marine animals mistakenly eat plastic debris because the tiny bits of the floating material might look like prey, the sightless corals eat the rubbish because of the taste, new research has found.
Visual cues, such as a resemblance to prey, do not factor into the appeal because corals have no eyes, said the study published online in the journal Marine Pollution Bulletin.
“Corals in our experiments ate all types of plastics but preferred unfouled microplastics by a threefold difference over microplastics covered in bacteria,” said one of the researchers Austin Allen, PhD student at Duke University in Durham, North Carolina.
“This suggests the plastic itself contains something that makes it tasty,” Allen said.
Microplastics, tiny pieces of weathered plastic less than five millimetres in diameter, began accumulating in the oceans four decades ago and are now ubiquitous in the marine environment.
They pose a major threat to foraging sea animals, including many species of birds, turtles, fish, marine mammals and invertebrates.
Because plastic is largely indigestible, it can lead to intestinal blockages, create a false sense of fullness or reduce energy reserves in animals that consume it.
“About eight percent of the plastic that coral polyps in our study ingested was still stuck in their guts after 24 hours,” Allen said.
“When plastic comes from the factory, it has hundreds of chemical additives on it. Any one of these chemicals or a combination of them could be acting as a stimulant that makes plastic appealing to corals,” Alexander Seymour, a geographic information systems analyst at Duke University, added.
