Are Coral Reefs Adapting to Climate Change?

A few weeks ago, scientists reported that climate change might actually be helping California's ancient trees thrive. Now there seems to be more positive news - This time about the coral in our oceans whose population has been severely impacted in last few decades by rising temperatures and ocean acidification, disease and human carelessness.

Coral reefs as you probably know are not just colorful calcium carbonate structures that provide sanctuary to a wonderful array of fish but also, a symbiosis or partnership between coral polyps and single celled organisms called zooxanthellae.

The coral polyps give the zooxanthellae a home and in return these organisms provide the polyps with their vivid color and food. The two species support each other in a delicate balance, one that is getting severely damaged by the rising temperatures which are causing the coral polyps to reject their zooxanthellae friends, both eliminating their color and their food source and causing the coral to appear as though it has been 'bleached'.

Scientists estimate that the 1998 El Nino bleached and killed almost 16% of the world's coral reefs. And if that is not bad enough, since 1977, this phenomenon combined with disease has decimated the Caribbean coral reef population by more than 80%. It is therefore no wonder that scientists all over the world are looking for solutions to try restore this all important link to marine life.

While human efforts like Ken Nedimyer's quest to save the reefs in the Florida Keys as well as the deployment of coralbots to re-plant the coral carelessly de-rooted by fishing trawlers have been somewhat successful, they are not enough to replace all the coral that has been dying due to climate change.

That is probably why reports by various researchers about certain types of coral being able to not only withstand the changing ocean conditions, but also, thrive in it, is being met with such enthusiasm. The most recent finding was revealed at the 2012 International Coral Reef Symposium (ICRS) by Hawaii Institute of Marine Biology's Christopher Jury, who reported that despite higher temperatures and acidity in Kaneoha Bay, Oahu, the coral reef there seemed to be thriving. A similar phenomenon has also been observed off the coast of Ofu Island in the American Samoa.

These findings are consistent with the lab research conducted in 2011 by California State University's Bob Carpenter and Peter Edmunds and Stanford University's John Pringle, who tried growing different varieties of coral in waters with higher temperature and acidity levels, to see how they would react. They were surprised to discover that most of them survived and some like the clade D type zooxanthellae and the coral species Polillopora damicornis seemed to adapt and and grow normally.

Encouraged by these and other similar findings, Florida's Nature Conservancy has started introducing heartier species to dwindling reefs, to see if they can be restored to their former glory. A program in association with Stanford University is busy analyzing the world’s oceans to find more resilient varieties that can be used for this same purpose.

However, we are not out of the woods yet! Scientists are still not sure how they would introduce these resilient varieties to areas where they are not abundant and more importantly what the consequences of introducing these 'foreign imports' would be on the surrounding marine life. Hopefully, the combination of new scientific research, curtailment in carbon emissions and fewer human mistakes, will allow our beautiful corals to thrive again!

Resources: scientificamerican.com,popsci.com