OUR PLASTIC WASTE IS DESTROYING THE WORLD’S CORAL REEFS

Our plastic lifestyle is killing coral reefs. A first-of-its-kind study published recently found that an estimated 11.1 billion pieces

of ocean plastic trash are lodged in coral reefs across the Asia-Pacific region, increasing corals’ susceptibility to potentially deadly diseases by as much as 89 percent. Scientists examined 124,884 corals at 159 reefs from Thailand to Australia, finding plastic bottles, bags, fishing line, and even Nike shoes wedged among colorful corals. The region is home to 55.5 percent of the world’s coral reefs, which harbor a quarter of marine species and provide food and livelihoods for hundreds of millions of people.

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“Plastics are a triple whammy for coral infections,” said Drew Harvell, a professor of ecology and evolutionary biology at Cornell University who conducted reef surveys in Indonesia for the study published in Science.

First, plastic debris can cut open corals’ delicate skin, exposing them to infection. Second, ocean plastic trash is often colonized by bacteria that can directly introduce disease to corals. And third, plastic can shade corals, blocking light and creating conditions that allow certain pathogens to thrive.

“These diseases are pretty damaging to corals,” Harvell said. “Once a coral has one of these diseases, it can kill the whole colony, and once an infection starts on one coral colony, it can build up steam and spread to other ones.”

“I think it’s a huge new impact to show that these plastics are so dirty that they can be creating wounds and infectious disease,” she added.

The researchers predict the amount of plastic caught on coral reefs will spike 40 percent by 2025 to 15.7 billion pieces.

The findings come as coral reefs are under unprecedented stress from climate change. Rising ocean temperatures have triggered back-to-back coral bleaching events in which the algae that live in corals and provide them with nutrition and their color, become toxic. The corals expel the algae and turn bone white. Deprived of nutrition, corals can die unless ocean temperatures cool and the algae return. A groundbreaking study published earlier this month concluded that coral bleaching—a phenomenon virtually unknown before 1980—is now accelerating at a rate that will not give reefs enough time to recover before the next heat wave hits.

OUR PLASTIC WASTE IS DESTROYING THE WORLD'S CORAL REEFS

“We don’t have the data to say whether infected corals would be more susceptible to bleaching, but it seems likely,” Harvell said. Also unknown is the extent that bleaching would make corals more vulnerable to pathogens transmitted by contaminated plastic.

Coral scientists are confident of the link between plastic contamination and coral disease, thanks to the study’s extensive surveys of reefs between 2011 and 2014. Researchers, led by Joleah Lamb, a postdoc in Harvell’s lab, laid down transects at each reef, covering an area that ranged from 645 to 1,290 square feet. The scientists examined every coral colony more than two inches in diameter, noting the presence of plastic and disease.

“The real strength of the data set is that it shows the correlation of coral health with plastic,” Harvell said. “I think we can be pretty definitive that plastics are contributing to the coral dying. It was not uncommon to find dead coral underneath plastic.”

Compared to plastic-free corals, the scientists found significantly higher rates of three debilitating diseases when corals come into contact with plastic: Skeletal eroding band disease (24 percent greater likelihood), white syndromes (17 percent increased likelihood), and black band disease (5 percent higher likelihood).

Study co-author Courtney Couch, a coral reef researcher at the National Oceanic and Atmospheric Administration in Honolulu, said the scientists did not determine which types of plastic might be more harmful than others. “Our surveys showed that 71 percent of the plastic debris surveyed was associated with textiles, household goods, packaging, and consumable items, while the remaining 29 percent was discarded fishing gear,” she said in an email.

OUR PLASTIC WASTE IS DESTROYING THE WORLD'S CORAL REEFS

“We don’t have the data to say whether infected corals would be more susceptible to bleaching, but it seems likely,” Harvell said. Also unknown is the extent that bleaching would make corals more vulnerable to pathogens transmitted by contaminated plastic.

Coral scientists are confident of the link between plastic contamination and coral disease, thanks to the study’s extensive surveys of reefs between 2011 and 2014. Researchers, led by Joleah Lamb, a postdoc in Harvell’s lab, laid down transects at each reef, covering an area that ranged from 645 to 1,290 square feet. The scientists examined every coral colony more than two inches in diameter, noting the presence of plastic and disease.

“The real strength of the data set is that it shows the correlation of coral health with plastic,” Harvell said. “I think we can be pretty definitive that plastics are contributing to the coral dying. It was not uncommon to find dead coral underneath plastic.”

Compared to plastic-free corals, the scientists found significantly higher rates of three debilitating diseases when corals come into contact with plastic: Skeletal eroding band disease (24 percent greater likelihood), white syndromes (17 percent increased likelihood), and black band disease (5 percent higher likelihood).

Study co-author Courtney Couch, a coral reef researcher at the National Oceanic and Atmospheric Administration in Honolulu, said the scientists did not determine which types of plastic might be more harmful than others. “Our surveys showed that 71 percent of the plastic debris surveyed was associated with textiles, household goods, packaging, and consumable items, while the remaining 29 percent was discarded fishing gear,” she said in an email.

OUR PLASTIC WASTE IS DESTROYING THE WORLD'S CORAL REEFS

“The only good news is that this should be easier to fix than climate change,” Harvell said.

This article originally appeared on Oceans Deeply, and you can find the original here. For important news about our world’s oceans, you can sign up to the Oceans Deeply email list.

By | 2018-08-08T12:18:44+00:00 August 3rd, 2018|News|