2016-02-24. How do you save a sick coral reef? Pop an antacid.

posted Feb 27, 2016, 7:25 AM by Alan Gould   [ updated Feb 27, 2016, 7:26 AM ]
By Eli Kintisch, Science. For GSS Losing Biodiversity chapter 7. Excerpt: Anyone who has ever dissolved a piece of chalk in vinegar knows that ocean acidification—the result of seawater absorbing carbon dioxide (CO2) pollution from the air—has to be bad for calcareous creatures like coral. But just how big a role does ocean acidification play in the sickly state of many reefs? ...Near shores across the planet, the health of reefs is in decline. Global studies have shown that major reef systems are calcifying—building their stony skeletons—more slowly, with one study suggesting growth rates of the Great Barrier Reef off Australia have plummeted 40% in just 3 decades. But lots of factors contribute to this harm: diseases, warming water, pollution, and sediment runoff, along with the 0.1 unit drop in the pH of the global ocean since the preindustrial era. ...scientists led by Rebecca Albright of the Carnegie Institution for Science in Stanford, California, set out to restore ocean chemistry to its preindustrial state at the One Tree Reef in the southern Great Barrier system. They released an antacidlike solution of sodium hydroxide into a lagoon in the reef, reversing acidification. ...Their calculations, published today in Nature, suggest that human alteration of ocean pH since the preindustrial era has reduced reefs' ability to calcify by 12%. The study “provides new field-based evidence that ocean acidification-induced changes in coral reef growth are already underway,” Albright's team said in a press release. ...But Carnegie geochemist Ken Caldeira, who oversaw the new study, says ...“Just to keep the oceans where they are and compensate for ongoing CO2 uptake,” he says, “you would need to add over 20 billion tons of limestone to the ocean each year. Not impossible, but a huge job. To undo the acidification that has already occurred you would need to add over a trillion tons of dissolved limestone. Not impossible, but highly unlikely.” The best way to protect reefs, he says, is to “stop treating the atmosphere like a sewer” by dumping CO2 into it, where the pollutant alters the climate and acidifies the oceans....  http://www.sciencemag.org/news/2016/02/how-do-you-save-sick-coral-reef-pop-antacid
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