Plastic is junk food for coral

Coral behaves unexpectedly when it comes to consuming plastic. Although it's well known that they do swallow microplastic particles, what is really strange is that they seem to actually like it.

Take a moment and try to imagine being a piece of coral. How does it feel to be sitting there, below the ocean's surface, swinging gently in a soft warm current, in a colorful and vivid environment (let's pretend everything's still fine down there). You have fish passing by, a boat crosses over your head, maybe a diver drops down and starts to explore your underwater hood.

Now, let's get a little bit more realistic. From the boat, and maybe from the diver, pieces of plastic garbage tumble down into your neighborhood. Over time this happens more often, more frequently. Slowly the plastic starts to break down into smaller, later very tiny pieces. What would you do?

Because you are a coral you would probably start to swallow some of those tiny pieces of plastic, just like the species around you do. But now something really strange happens. You actually start to like the taste of those plastic bits. Not of all of them, but some.

Boy, that's yummy — but why?

Surprisingly, that's exactly what scientists at Duke University's Nicholas School of the Environment found out. I mean, scientists have known for a long time that marine animals mistakenly eat plastic debris. They thought it was mainly because the tiny bits might look like prey. But a new study suggests there may be an additional reason for the potentially harmful behavior: The plastic just plain tastes good.

"Corals in our experiments ate all types of plastics but preferred unfouled microplastics by a threefold difference over microplastics covered in bacteria," said Austin S. Allen, a PhD student at Duke.

So, the scientists figured that the plastic itself would contain something that makes it tasty.

"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," said Alexander C. Seymour, who co-led the study with Allen.

More research is needed. But these first, and indeed surprising results were published October 23 in the online edition of the journal Marine Pollution Bulletin.

Time running out to save the world's coral reefs:

Time running out to save the world's coral reefs

Trouble in paradise

Some 2,500 scientists, policymakers and managers came together in Honolulu in June 2016 for the world's largest summit dedicated to the future of coral reefs. With coral reefs threatened by global warming, participants at the 13th International Coral Reef Symposium are calling for a joint rescue effort.

Time running out to save the world's coral reefs

World is watching

The event gathered guests from 97 countries, including the presidents of Palau, Micronesia, and the Marshall Islands. Coral reefs are a key source of income in those countries, mostly through tourism.

Time running out to save the world's coral reefs

Too warm for comfort

The Pacific nations are worried about the future of their tourist hotspots, as coral reefs face so-called "bleaching" due to rising sea temperatures. "If our coral reefs are further degraded, then our reef-dependent communities will suffer and be displaced," leaders of Palau, Micronesia, and the Marshall Islands said in an open letter.

Time running out to save the world's coral reefs

Corals in crisis

Bleaching happens when coral is stressed by hot ocean waters or other changes in the environment. In response, corals may release tiny symbiotic algae which drains them of color. More importantly, bleaching affects their ability to feed and reproduce.

Time running out to save the world's coral reefs

Pale as death

Severe or prolonged bleaching might kill off corals entirely. Scientists have detected bleached coral in the past two years in oceans around the world. They expect the process to continue thought 2016.

Time running out to save the world's coral reefs

Giant from Down Under

The 2,300-kilometer-long (1,429-mile-long) Great Barrier Reef is the world's largest coral reef system and its largest living structure. It is also among Australia's main tourist attractions, generating around $3.9 billion (3.5 billion euros) annually.

Time running out to save the world's coral reefs

Tough times for the Great Barrier Reef

Almost one-half of the coral in the reef's northern third have died in the past three months, according to James Cook University professor Terry Hughes. The most affected area is remote and unpolluted, with very little fishing and no coastal development. "That's an absolute catastrophe," Hughes said. "There's nowhere to hide from climate change."

Time running out to save the world's coral reefs

Fighting for hope

Despite the bad news, scientists claim the problems can be managed with proper funding and political backing. "We are not ready to write the obituary for coral reefs," Professor Hughes said. The scientific community at the conference pledged to work with leaders across the world in order to "curb the continued loss of coral reefs."

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