The following article was written for Go Gulf Magazine.
You might not expect to find coral reefs teaming with an endless variety of brightly colored fish located among the oilrigs of the gulf. But if you head seventy miles straight south from Sabine Pass, that is exactly what you will find. A century ago, snapper fishermen thought these reefs looked like flower gardens, and the name stuck; the reefs are now part of the Flower Garden Banks National Marine Sanctuary. The sanctuary consists of three reefs, The East, West and Stetson Banks, and it is one of thirteen Flower Garden sanctuaries managed by National Oceanographic and Atmospheric Administration (NOAA).
The reefs have it all, from zooplankton to the largest fish in the world all flourishing in close proximity to the offshore oilfields. Over the years, with the help of the oil industry, the NOAA staff at the sanctuary has protected, monitored, and facilitated research upon these surprising reefs.
The banks were first thrust upward by salt domes forming millions of years ago, and now support a diversity of species unique on the gulf coast. Another unique aspect of the reef system is that it lies far from the shoreline. This isolation allows it to thrive in the absence of pollutants that have damaged other systems closer to shore. Dr. Quenton Dokken, at the Center for Coastal Studies, notes that "it's remarkable that such a healthy and productive reef system exists right in the middle of the most active offshore exploration and production area in the world."
The northernmost of the three Flower Garden Banks, the Stetson Bank, lies in slightly cooler waters. The temperature difference prevents it from supporting as much diversity as the other two banks. It supports mainly communities of sponges. However, the east and west banks, near the water's surface, are just what you might expect from a tropical reef, with hundreds of species of fish and invertabrates and heads of coral the size of automobiles. The loop current of the gulfstream allows these reefs to thrive at the northernmost limits of coral reef habitat.
Starting at depth of 90 feet on the east and west banks, you can find areas next to larger corals with many small branching finger coral called Madracis Mirabilis. These areas also feature finger sponges, encrusting sponges, and algae. Divers find sponges, algae, and coral that flattens out to take advantage of all available light as they travel deeper on the reef. At greater depths, the diver finds strange animals like the bedspring-shaped antipatharian sea whip. Below a depth of 270 feet, coralline algae survive, but reef-building corals cannot. The deeper portions are what is left of the ancient reefs, which probably formed when sea levels were lower and these ancient reefs were closer to the surface.
On the Gulf's floor at 300 to 400 feet down, only sand or mud bottom surrounds the reef. Though they look barren, the surrounding bottom hosts a healthy community of organisms surviving in the sediment. Micro algae, worms, crabs and sea stars all manage to flourish at these depths. On the East Bank at depth of 220 feet lies a salt lake 200 feet wide by only 10 inches deep, formed from the brine that seeps out of the salt dome beneath. The forbidding, heavy, highly saline water with its high concentrations of hydrogen sulfide and hydrocarbon gases does not support marine life.
However, the bottom of the reef is not the only forbidding area. In winter, bad weather on the water's surface harries but does not stop researchers from documenting the shark and ray populations. Schools of scalloped hammerhead sharks and spotted eagle rays gather around the Flower Garden and Stetson Banks. Sandbar and tiger sharks also come to the banks in winter. Large schools of silky sharks congregate around the High Island platform at the edge of the sanctuary, only a mile from the East Bank. Manta rays feed at the edges of the banks all year, southern stingrays lie in the sand flats, and devil rays visit the sanctuary in the early summer. As summer wears on, recreational divers may even have encounters with the largest of all fish, the whale shark. Whale sharks at lengths of 35 feet have been sighted at the Banks.
This diversity of marine life, unusual to the Gulf Coast, makes the Flower Garden Banks a popular destination among scientists and recreational divers. Often, because of sometimes-scarce funding, the Flower Garden Banks National Marine Sanctuary researchers charter recreational dive boats to double as research boats. Sometimes the researchers use NOAA ships, but much of the time the whole operation depends heavily upon cooperation with the oil industry.
Among the guardian angels of the Flower Garden staff over the years have been the platform operators in the area. Scientists occasionally hitch rides out to the platforms and store equipment onboard after their forays out to the reef. G.P. Schmahl, the Sanctuary Manager, is continually developing relationships with the gas and oil industry and welcomes all assistance. The oil industry is integral to the NOAA's research and monitoring efforts, the oil platforms serving as a base for biologists and divers and also as a mount for monitoring instruments.
For additional information or to offer assistance to the Flower Gardens Bank National Marine Preserve, call 979-779-2705, fax 979-779-2334, or go online at Scientists occasion-www.flowergarden.nos.noaa.gov.