Ocean acidification could help decrease the persistence of a nasty coral disease, according to a first-of-its-kind study that included a team from Mote Marine Laboratory in Sarasota.
In a study published in the journal PLOS ONE on June 1, researchers and students from around the country looked at how deadly coral diseases would be affected by changing ocean conditions. They found that black band disease, a fast-acting collection of bacteria that form circles across at least 42 different coral types, was less deadly when exposed to acidic water.
In a changing underwater climate, sensitive corals are being weakened and killed by warmer temperatures, more acidic waters and a number of diseases. Water becomes more acidic when it has more carbon dioxide — also the culprit for growing global temperatures. The increased carbon dioxide causes coral skeletons to crumble, according to Mote, and warm water makes coral lose the algae in their tissue.
During the 16-day study in 2013, the scientists looked at the endangered mountainous star coral found in the Florida Keys and put the specimens into environments based on year-2100 projections made in the Fifth Assessment Report from the Intergovernmental Panel on Climate Change. The controlled areas to match seawater had a pH of 8.1, whereas the test conditions had a pH of 7.7.
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While warm water had little effect on the disease, the low pH environment slowed the disease by 25 percent, according to Dr. Erinn Muller, the lead author and manager of Mote’s Coral Health and Disease Research Program. Studies done on different coral species had similar effects.
Although associate professor at the University of South Carolina at Beaufort Dr. Kim Ritchie said in a Mote press release that the amount of Oscillatoriophycidae, the cyanobacteria that mainly makes up black band disease, was reduced, not being able to survive in areas of elevated acidity.
“One of our next steps is to study how low pH influences the very small scale conditions in the micro-environment of black band disease as the outside environment changes,” Muller said in the press release.
This is just a potential glimpse at what corals could be facing in the future.
“We’re still trying to understand how projected ocean acidification will impact mountainous star and other corals over the long term, and how it might interact with coral diseases,” said Hayley Rutger, content development manager for Mote, in an email to the Bradenton Herald. “The research focuses a bit less on deciding which is worse, and more on deciding how corals will handle both threats (and others) happening at the same time.”