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Coral Reef Off Florida Determined to be Deepest Known on U.S. Continental Shelf
Consultation with colleagues at numerous national meetings has helped a team of scientists determine that a coral reef off the southwest coast of Florida is the deepest ever found on the U.S. continental shelf. Scientists and graduate students from the University of South Florida (USF) and the U.S. Geological Survey (USGS) discovered the deep coral reef and diverse fish populations while conducting collaborative research west of the Dry Tortugas in 1999. USGS marine geologist Robert Halley was on the team that made the discovery. "Although deeper-water corals form reefs in the dark of ocean depths, [the reef at] Pulley Ridge is the deepest photosynthetic coral reef that we know of today," said Halley. The reef lies in approximately 250 ft of water off the coast of southwest Florida on a series of drowned barrier islands collectively named Pulley Ridge. A long, north-trending feature, Pulley Ridge was originally discovered in 1950 when an academic group from Texas conducted dredging and hauled in mollusks. The ridge hosts the unusually deep photosynthetic-coral reef on its southern section. The deep coral reef is 20 mi long and 3 mi across at its widest point and covers an island that was submerged 13,000 years ago. It is a significant discovery that may be unique. The southern Pulley Ridge coral reef has been the subject of several research cruises since its discovery in 1999. In June 2001, for example, Halley and USGS research assistant Kate Ciembronowicz took part in a National Geographic Sustainable Seas Expedition to the reef during which they collected bottom-sediment samples and used a one-person submersible to shoot video footage (see Sound Waves article, USGS Scientists Team Up with National Geographic's Sustainable Seas Expedition to Explore Deep Reefs at Pulley Ridge). In spring 2003, USGS and USF researchers used the USGS SEABOSS (Sea Bottom Observation and Sampling System) to collect video transects, still photographs, and coral and algae samples from along the ridge (see Sound Waves article, USGS Scientists Use the SeaBOSS to Explore What Could Be the Deepest Coral Reef in the Continental United States). The SEABOSS—a modified van Veen grab sampler in a stainless-steel frame with integrated still photography and video systems—is the source of the photographs that accompany this article. Another Pulley Ridge research cruise will take place this year, with USGS scientists joining colleagues from the Harte Research Institute for Gulf of Mexico Studies at Texas A&M University, Corpus Christi, and from the Florida Department of Environmental Protection. The corals on Pulley Ridge are considerably healthier than those from shallow-water reefs nearly worldwide, including those in the Florida Keys. Corals are normally found in shallower water because they require large amounts of sunlight, but research shows that shallow corals are stressed and vulnerable to disease, global climate change, loss of habitat, and human activity. The Pulley Ridge reef provides pristine habitat for giant red grouper, bass, scamp, damselfish, angelfish, rock beauty, and hogfish. Remote-sensing images, video clips, and numerous color photographs of the area's sea floor, fish, and corals are available online on the Pulley Ridge Web site. Because many of Florida's coral reefs are in decline, the Gulf of Mexico Fisheries Management Council has taken steps to protect Pulley Ridge. On January 13, 2005, at a meeting in Baton Rouge, LA, the council voted to make a 100-mi2 area centered around Pulley Ridge a Coral Essential Fish Habitat. This designation carries with it a set of regulations that prohibit such fishing activities as anchoring, long-line fishing, trawling, and use of buoyed traps or pots. Various activities that do not disturb the bottom, such as drifting over the site and suspending a fishing line in the water, are still allowed.
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in this issue:
Pulley Ridge Deepest Known US Coral Reef Climate Features Influenced 2004 Hurricane Landfall Count
Oceanographer Joins Western Coastal & Marine Geology Team Netherlands Students Contribute to USGS Studies Florida Integrated Science Center, Gainesville, FL |
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U. S. Department of the Interior | U.S. Geological Survey
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