Cold snap triggered massive coral die-off

While warming seas are a leading cause in the decline of the world's coral reefs, U.S. researchers have discovered cold temperatures can be just as devastating. Scientists are the University of Georgia conducted a study of coral reefs in the Florida Keys following an abnormal episode of extended cold weather in January and February 2010 when temperatures on inshore reefs dropped below 54 degrees F and remained below 64 degrees F for two weeks. When the researchers arrived just three weeks after the cold snap at Admiral Reef of Key Largo, they found the reef, once abundant in hard and soft corals, was essentially dead, a UG release reported Monday. ""It was the saddest thing I've ever seen,"" post-doctoral ecologist Dustin Kemp said. The ""large, reef-building corals were gone. Some were estimated to be 200 to 300 years old and had survived other catastrophic events, such as the 1998 El Nino bleaching event. The severe cold water appeared to kill the corals quite rapidly."" Taking samples back to their lab, they simulated the temperatures that had been recorded at Admiral Reef and tested the different corals' physiological. They found that although responses varied depending on the coral species, in general the stress of extended cold temperatures had an effect similar to that of high temperatures. Kemp said that the study's findings should not be interpreted to downplay the major role of higher temperatures on corals' decline, but that ""the study shows that warming may not be the only climate-related problem for coral reefs in the future.""