The brightly hued reefs that fringe the Florida Keys are turning to dingy shades of death, and a Georgia zoologist has found that car-sized chunks of slow-growing coral have disappeared in four years.
Portions of mainland America`s only living coral reef are dwindling at rates of up to 10 percent a year, said James Porter, a zoologist at the University of Georgia in Athens. He will present his findings Friday at the annual meeting of the American Society of Zoologists in Atlanta.
”I`m trying to be a scientist, not an alarmist,” said Porter. Still, he added, he was startled by what he learned.
”If that loss rate continues, those Florida coral reefs will be gone in 10 years,” said Porter. ”There will be algae there.”
Global warming, shoreline development and sewage may be triggering the problems, but Porter said it is difficult to pinpoint a culprit.
”I`m a scientist. What I want to do is have specific cause and effect,” he said. ”We don`t know whether the near-shore human activity is causing the decline of offshore coral reefs” at his study sites 3 to 5 miles from the coast.
Recent research has shown that pollution may reach the reefs via cross-channel currents moving from the shore.
Up to 10 percent of the coral disappeared from Porter`s study area in the Looe Key National Marine Sanctuary, said the zoologist, who has been studying the Keys reefs since 1984. Sampling stations in the Key Largo National Marine Sanctuary and Biscayne National Park showed lesser declines.
Florida`s reefs begin to appear in patches off Palm Beach and become more well-developed off the Keys. The area attracts thousands of visitors annually- many of them divers and snorkelers-and pumps millions of dollars into South Florida`s economy.
Porter set out to study reef growth in those three locations, but what he found instead was the area`s demise. In 1984 he was photographing thriving reefs. By this year, some of the reefs had dwindled to ghostly skeletons or had broken apart.
A University of Miami scientist who also is studying the reefs says Porter`s studies are well done, but contends his projection of coral death within a decade is premature.
”The situation here in Florida is a very complicated one,” said Alina Szmant, assistant professor of marine biology and fisheries at the University of Miami. ”You can`t study one little piece of the pie and assume what you`re looking at applies to the whole pie. That may or may not be true.”
Coral reefs such as the ones in the Keys grow in a tropical or subtropical environment. Florida reefs have a precarious existence because they exist at the fringes of the environment they need.
”This is a very marginal area for reef growth at this time,” Szmant said. ”The decay is measurable and it`s spotty. . . . He doesn`t know that if he went two reefs over, they might have had an increase.”
Taken as an entire tract, the reefs off the Keys have been declining for about 4,000 years, Szmant said, although some patches are doing better than others.
Before drawing conclusions about a decline, Szmant said, Porter should study more areas and do it for a longer time.
Studying more areas would be helpful, Porter agreed, but said his areas were representative. Each was surveyed in several ways, including the use of detailed photographic records of small plots. More than 5,000 individual corals were examined.
”I expected to see the branching corals increase rapidly and the brain corals and head corals increase slowly,” he said. ”All species showed deterioration and decline.”
The problems are serious and merit public debate, he said.
”Everybody can wave their arms and have their own opinions about what is happening,” Porter said. ”But we have data.”
Three problems predominated: Coral bleaching, black band disease and white band disease.
These problems are linked to rising water temperatures or pollution, but exact causes have not been pinpointed, scientists say.
Federal officials, aware of Porter`s research, are conducting their own research on the reefs. They say some of the problems may be tied into larger patterns, such as regional or global climatic changes.
Said Edward Lindelof, branch chief in the marine sanctuaries program at the National Oceanic and Atmospheric Administration: ”A lot of this stuff may be . . . changes that are well beyond our ability to control.”
