Dead reefs may come back to life, says study

(CBS News) The widespread collapse and death of coral reefs in oceans around the globe is considered one of the most important environmental challenges in the world. A new study from the Florida Institute of Technology says that there may be hope for dead reefs. It is possible that coral reefs may be able to weather the storm of climate change and regrow - it's happened before.

Richard Aronson and his team at FIT studied coral reefs off the Pacific coast of Panama. The reefs in this corner of the ocean are vibrant and home to hundreds of species of ocean-dwellers. The FIT team took core samples from the reefs to determine their lifespan, much like tree experts count the rings of trees.

"We jammed 17-foot-long irrigation pipes down into the reef and pulled out a history, a section of the reef, that told us what the ups and downs of the reef had been," Aronson said in an interview with NPR.

The results were surprising. The 6,000-year old reefs lived a far more varied life than their immobile nature would suggest. The reef grew faster or slower in response to ocean temperatures. It had even died.

"These reefs were shut down for 2,500 years," Aronson said, "and the reefs have only been living for 6,000 years, so that represents about 40 percent of their entire history. So that's really shocking."

Aronson and his colleagues, including researchers from an array of institutions, believe that natural climate change was responsible for killing off the coral. They point to the effects of El Nino and La Nina, two weather events which can drastically change the ocean temperature. These events were far more extreme in the 2,500 year period under study from Aronson. However, once the global climate moderated those extremes, the reefs began growing again.

"It seemed to be fairly instantaneous," Aronson told NPR. "About 2,000 years ago or so, some corals that are not the main reef-building corals started up, and then maybe 500 years later, around 1,500 years ago, the main coral started growing again very rapidly."

Naturally, the FIT study hopes to look to the future by peering the past. If coral reefs were able to survive rising ocean temperatures in the past, it is possible they can do so again. Global climate change could lead to noticeably higher water temperatures, with devastating consequences for sensitive coral reefs. 

Aronson, for his part, is looking on the bright side.

"What [this study] tells me is that these reefs do have hope, and if we are able to get a handle on climate change, then we might be able to save coral reefs," Aronson said.