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Sunday, October 16, 2011

Good news/bad news about coral reefs


First, the bad news.  Thanks to climate change, coral reefs around the world are in trouble.  Increased carbon dioxide is making the oceans more acidic, which interferes with the corals’ ability to build their exoskeletons.  In addition, the warmer temperatures themselves result in ‘coral bleaching’ or the loss of symbiotic algae from within the coral bodies.  As corals get most of their nutrients from the photosynthetic efforts of these algae, bleached corals do not survive for long. 

Many experts predict that coral reefs, which support a quarter of all marine life, will go extinct unless we can drastically reduce carbon levels.   In other words, it won’t be enough to immediately reduce emissions.  To protect corals, we would need to actively suck carbon dioxide out of the atmosphere. 

Now a bit of good news.  Researchers led by Arnaud Brayard of the Universit√© de Bourgogne have found that coral colonies can recover much more quickly than previously thought.  During the Permian/Triassic extinction event of 252 million years ago, 90% of all species went extinct, including many types of coral.  Previously, paleontologists assumed that it took about five million years for coral reefs to recover, but new evidence suggests that it only took…wait for it… about 1.5 million years.

Okay, that’s not really all that good.  Still, it does give some hope for the distant future.  And if we can cut emissions now, we may be able to avoid having to wait 1.5 million years for corals to recover.