Your Face Scrub Could Be Starving Coral Reefs

Scientists find corals are eating as much plastic as food, and this can kill them.

(Photo: Mark Conlin/Getty Images)

Feb 27, 2015· 1 MIN READ
Taylor Hill is an associate editor at TakePart covering environment and wildlife.

The ocean’s corals have a lot to deal with these days.

Ever-increasing greenhouse gas emissions are warming ocean temperatures, bleaching and sometimes killing coral reefs that shelter fish that end up on your dinner plate. The seas are absorbing carbon dioxide from the burning of fossil fuels, which is acidifying the oceans and retarding the growth of coral.

Now Australian researchers have found that the 8 million tons of plastic we dump into the ocean each year are being eaten by corals, which gums up their digestive tracks and can lead to starvation.

Photos ‘a’ and ‘b’ show microplastics in the mouths of coral
polyps. Photo ‘c’ shows plastic fragments found in the
water near reef sites. (Photos: N.M. Hall)

By nature, corals are not picky eaters, said study coauthor Mia Hoogenboom of ARC Centre of Excellence for Coral Reef Studies at James Cook University, and the 5 trillion pieces of plastic floating in the water today look just as enticing to the organisms as their favorite meal, zooplankton.

Researchers took corals from the Great Barrier Reef and put them in water littered with microplastics—five-millimeter bits or smaller that make up most of the ocean’s total plastic pollution. They found that the coral polyps ate almost as much plastic as the marine plankton they were supposed to be eating, and the tiny plastic pieces ended up lodged deep in their gut cavity tissue.

Coral gets energy in part from photosynthesis, but the symbiotic creature needs that gut tissue to digest food. If it’s jammed up with plastics, it could slowly starve to death. Scientists studied the water around the Great Barrier Reef and found bits of plastic there too—just in smaller numbers.

“If microplastic pollution increases on the Great Barrier Reef, corals could be negatively affected as their tiny stomach cavities become full of indigestible plastic,” Hoogenboom said.

Coral is just the latest organism found to be dealing with plastic pollution.

Hundreds of marine species are trying to cope with increasing encounters with plastics they come across in the sea. In a recent study, researchers found that plastics were the culprits in 92 percent of marine animals’ reported encounters with debris. Those encounters usually involved animals either eating plastic bits or getting tangled in plastic rope or netting and resulted in injury or death about 80 percent of the time.

Still, the effects of microplastics have been understudied, and there is a need “for further investigation of whether and how microplastic contamination influences the physiology, growth, and survival of marine organisms,” the authors wrote.