Coral growth slows as ocean becomes more acidic

Experimental plume of carbon dioxide-enriched seawater and a dye tracer flowing across a coral reef flat in Australia's Great Barrier Reef.
An experimental plume of carbon dioxide-enriched seawater and a dye tracer on a coral reef in Australia's Great Barrier Reef. Photo: Aaron Takeo Ninokawa/UC-Davis Bodega Marine Lab

Ocean acidification cut the growth of a coral reef on Australia's Great Barrier Reef by one-third, according to a study published Wednesday in Nature. By simulating a more acidic environment, researchers were able to look at the effect of carbon dioxide on multiple reef species in their natural habitat for the first time.

Why it matters: Hundreds of millions of people around the world rely on coral reefs — for food, income from tourism and protection from tsunamis and storms. The study suggests the combined impact of coral bleaching from increased water temperatures and ocean acidification from carbon dioxide emissions could impair a reef's ability to recover.

"They’ll be hit by two stressors simultaneously so the effects could be worse than what we expected from lab studies...The bleaching events we see today that look scary could be even worse when compounded by a falling pH."
— University of Miami's Chris Langdon, who wasn't involved in the study