Great Barrier Reef Corals Eat Microplastics

Before you rejoice over a possible solution to the ongoing plastic pollution problem, know that Great Barrier Reef corals that eat microplastics may be putting themselves at risk with their unique appetite, according to a new study.

Normally, corals ingest zooplankton, sediment and other microscopic organisms, including algae which they rely on for energy from photosynthesis. However, it appears they inadvertently take in microplastics as well, which researchers fear can impact their digestive process and lead to harm.

"Corals are non-selective feeders and our results show that they can consume microplastics when the plastics are present in seawater," Dr. Mia Hoogenboom, a Chief Investigator with the ARC Centre of Excellence for Coral Reef Studies at James Cook University, said in a news release.

"If microplastic pollution increases on the Great Barrier Reef, corals could be negatively affected as their tiny stomach-cavities become full of indigestible plastic," she added.

With 8 million metric tons of plastic riddling the world's oceans, it's no surprise that various marine organisms are put at risk, including corals. Whales, dolphins, sea birds and crabs are also among the 700 marine species feeling the effects of our plastic pollution. And with Great Barrier Reef corals already suffering from ocean acidification, adding microplastics to their list of threats spells bad news.

To determine whether these corals indeed ingest microplastics as part of their diet, reseachers put corals collected from the Great Barrier Reef into plastic contaminated water. After two nights they found that the corals had eaten the plastic particles.

"We found that the corals ate plastic at rates only slightly lower than their normal rate of feeding on marine plankton," said study lead author Nora Hall.

Specifically, the plastic was found deep inside the coral polyp wrapped in digestive tissue, raising concerns that it might impede corals' ability to digest its normal food.

What's more, the team found microplastics - albeit in small amounts - in waters adjacent to inshore coral reefs on the Great Barrier Reef, including polystyrene and polyethylene. Researchers next plan to study the impact plastic has on coral physiology and health, as well as its impact on other marine organisms.

Their findings were published in the journal Marine Biology.

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