FEATURE - Tortugas shining light in Florida's damaged reefs
Date: 29-Aug-02
Country: US
Author: Jim Loney
The pale light that filters from above reveals scaly plates creeping over a stony plateau and downy fingers reaching skyward. Crimson boulders glow, lit by some internal fire.
Unlike the legendary Nottinghamshire lair of Robin Hood, this fantasy land called Sherwood Forest is not a royal hunting ground and hide-out for wily outlaws but a real and rare tract of pristine coral reef under 80 feet (24 metres) of subtropical Florida waters forbidden to maritime hunters.
Some scientists see it as a refuge of hope in a spiraling undersea crisis.
"This is one of the best remaining coral reef habitats in the United States and the best nursery habitat in the United States," said Billy Causey, a marine biologist who as superintendent of the Florida Keys National Marine Sanctuary is chief guardian of the Dry Tortugas reefs.
A tiny cluster of sand and coral islands, the remote Dry Tortugas - discovery credited to Ponce de Leon in 1513 - host perhaps the United States' best-protected coral reefs.
While technically part of the Florida Keys, the Tortugas are 70 miles (113 km) of open water from the rest of the Keys, a 100-mile-(161-km) long chain of islands connected by bridges off the southern tip of the Florida peninsula.
The barrier reef that lies about 6 miles (10 km) seaward of the Keys has deteriorated badly in the last two decades, suffering the ravages of global climate change, polluted water running off the Florida mainland and damage from scuba divers and fishermen who are part of a booming Keys tourist economy welcoming more than 2.5 million people a year.
TEEMING WITH LIFE
In contrast to the patchy coral at most of the Florida Keys barrier reef, the Dry Tortugas are teeming with life.
Florida Keys charter boat captain Tim Taylor is generally credited with naming Sherwood Forest.
"After 20 years of diving down here, the formations are different than anywhere I've ever seen," he said. "It looks like the floor of a forest, a giant forest, with the ground cover spreading out and the light filtering down from above."
Sherwood Forest is largely flat, like a vast coral plain, contrasting sharply with the canyons and mounds of most reefs.
It is probably the oldest, and possibly the largest coral reef tract in the Florida Keys, said Walt Jaap, a research scientist at the Florida Marine Research Institute.
"It goes back over 9,000 years," Jaap said. "It's a huge reef, one of the largest expanses of reef we know of, miles long and a mile in width."
Coral reefs are fragile geological marvels constructed by tiny creatures called polyps, which grow on a limestone base. Ornate and visually stunning, they are often compared to flower gardens and are considered vital to the health of surrounding water, hosting microscopic organisms on which larger creatures feed and providing shelter for fish, lobster and other life.
Reefs grow slowly, as little as half an inch (1.25 cm) per year, and polyps need the right combination of light, warmth and pure water to survive.
At Sherwood Forest and nearby spots with names like Gary's Grotto and Anne's Rolling Hills, leafy lettuce corals and scroll corals abound. Tube sponges appear in amber and pale green. Great star coral boulders shine crimson and orange, their fluorescent pigments emitting color even at depths where reddish tints normally disappear.
At 80 feet (24 metres), rare black corals appear. Cherished as jewelry in some parts of the world, they are more beautiful still in their natural state, with slender branches like conifer boughs coated in filaments of emerald and aqua.
"We're seeing 40 (percent) to 60 percent coral cover here," Causey said. "Up the Keys our scientists are seeing 5 percent up to 15 percent, but mostly 5 percent."
MAN ON A MISSION
A graying, stocky marine biologist who began diving in the '50s and once collected tropical fish for a living, Causey, 58, speaks zealously about the need for "marine zoning,"