Climate change increases problems for Florida reefs

Miami Herald: The last, largest stands of ancient elkhorn coral survive in shallow waters off North Key Largo, where rough seas sometimes expose thick golden branches reaching toward the sunlit surface. Forty years ago, elkhorn grew in dense forests that would cover parking lots. Now, the biggest clump would barely fill one space. In another 40 years, elkhorn could disappear altogether -- along with just about every other hard coral forming South Florida's once-vibrant barrier reefs.

Federal regulators last week designated a 1,329-square-mile strip of sea bottom stretching from southern Palm Beach County to the Dry Tortugas as critical habitat for elkhorn and staghorn corals, two species that have long formed the foundation of barrier reefs off Florida and in the Caribbean. But a new report by the Environmental Defense Fund and co-authored by two University of Miami scientists argues localized protections will do little to address the biggest threat to reefs.

Global warming is not only accelerating problems that already have sickened and shrunken coral reefs, it has created a new, potentially more lethal threat: Increasingly acidic ocean waters that can reduce living coral to dead rubble. The report, ''Corals and Climate Change: Florida's Natural Treasures at Risk,'' concludes that 5,000-year-old reefs, which support an array of marine life, will be among the first ecosystems to collapse if greenhouse gas levels continue to rise in the atmosphere….

Elkhorn coral (Acropora palmata) is a branching coral. Branching corals grow in the shallow areas of the reef crest and serve to break up the wave action as it comes onto the reef. The branches of elkhorn coral resemble an elk's rack of antlers, thus its name. (photo: Paige Gill - Florida Keys NMS)