Researchers off of the coast of Florida discover rare algae, coralline lace worms and mollusks thriving on flickering fingers of light.
By Anne Jungen
Robert Halley calls it a miracle.
Nature and technology worked together almost flawlessly with Halley and 30 other scientists and researchers during an eight-day exploration of the recently discovered Pulley Ridge coral reef. The crew brought back a slew of new scientific data, samples and photos from the reef off of Florida's gulf coast when they returned to St. Petersburg's Bayboro Harbor on July 1.
The crew discovered rare types of marine life, including some possible new discoveries. Among the life forms: green and red algae, coralline lace worms and mollusks. Researchers also made significant progress in mapping the reef's unique characteristics, which provide clues to the area's evolution and ecology.
The reef, believed to be as much as 14,000 years old, is the deepest known light-dependent coral reef in U.S. waters and surprisingly healthy; the coral was free of disease or the ravages of pollution. Halley, chief scientist of the expedition, called it one of the most significant finds in recent history.
A range of data and samples are on their way to the Smithsonian Institution, U.S. Geological Survey and institutions around the U.S. and abroad for analysis. Results should be back within one year.
The 125-mile reef was first identified in early January by researchers from the University of South Florida's College of Marine Science and U.S. Geological Survey Center. It rests 100 miles off of Naples in the Gulf of Mexico, about 200 miles from St. Petersburg. It sits on ancient, submerged barrier islands 200 to 250 feet below the surface, while most reefs exist no deeper than 150 feet.
How a reef that depends so heavily on light can flourish at that depth baffles even the experts.
"It's a mystery," Halley said. The reef is bathed in warm, clear water carried there by a loop current, a circulation movement in the gulf, which washes up along the Florida shelf from the Caribbean Sea, Halley said.
John Ogden, director of the Florida Institute of Oceanography, said the remarkably clear water allows sunlight to penetrate the depth of the reef. That allows the plants and corals to survive, along with tiny, one-celled algae. Still, scientists say, for photosynthesis to function so well so far below the surface, and allow the organisms to thrive, is amazing.
"It's an unusual community of coral and algae living in luxury deeper than you would expect," Ogden said. The expedition crew, traveling on four ships, also included researchers from the the Harte Institute of Texas A & M University and Mote Marine Laboratory in Sarasota. They worked round-the-clock for eight days.
Sylvia Earle, co-chief scientist of the expedition from Oakland, Calif., said the reef is populated by several species of "round, thin amazing plate-like coral." The reef also contains an important fish community that provides larvae for reefs downstream. "There's nothing like it in the world," Earle said. "We can't lose that." Intertwined with a "gorgeous splash of colors" of coral, researchers discovered a scientific treasure trove.
"There are a number of organisms that, if not new, are really rare elsewhere, but common on the reef," Halley said.
When the expedition returned to dock before a waiting crowd of reporters and scientists, Earle triumphantly displayed a handful of the brilliant green, lettucelike algae. Divers discovered acres of the rare algae on the reef, and vast "suites" of red algae.
They also stumbled upon shell-less mollusks, creatures similar to snails. Halley said it's not known if they exist anywhere else.
The seafloor on the northern part of the reef was blanketed with meadows of millions of small coralline lace worms, tiny worms that build tubes resembling upright angel-hair pasta - something Halley had never seen before. "To our knowledge, it's a phenomenon that's unique," Earle added. The health of the reef makes it ripe for more research, and especially exciting. Halley said most shallow water reefs have been suffering from coral diseases, over-fishing and pollution.
"We've seen a general worldwide decline in amount of live coral on coral reefs," he said. But the Pulley Ridge reef showed none of the devastation common to reefs in shallow water or closer to shorelines. Halley said the reef's depth seems to have protected it.
Preparation for the expedition took six months, involved the teamwork of several organizations and employed an array of technology. Once on the water, crews were blessed with good weather, pausing only occasionally for storms, currents or high winds. "I'll be beaming for a long time," Halley said. The expedition included a one-man minisubmarine for photography, a remotely operated underwater vehicle and a team of scuba divers, who carried tanks with a mixture of oxygen, helium and nitrogen in order to breathe at great depths. Divers could explore for only 20 minutes before they had to return to the surface to decompress.
Al Hine, co-chief scientist of the expedition and associate dean of research and professor of marine science at USF, headed the geophysical, or mapping, aspect of the expedition. Its goal: to determine where the most coral was growing. Geophysical data was collected mainly using side-scan sonar, instruments that are towed behind the ship and produce images of the seafloor, and high-resolution seismic reflection profiling, which works by bouncing sound waves to penetrate different types of rock. Though scientists will analyze the data for the next couple of months, Hine believes they have a relatively accurate map. They discovered four shorelines on the ridge, which means the ridge used to be dry land.
"It's a fundamental discovery of what's out there," Hine said.
And that discovery, Halley said, shows how much remains to be discovered about the ocean floor. He said scientists know more about the surface of the moon than what's beneath the water.
