Tuesday, July 10, 2001

Wilmington, NC-- The Gulf of Mexico is the nation’s most important offshore energy resource for oil and gas, and economically important for marine transportation and fisheries resources. The University of North Carolina at Wilmington and its National Undersea Research Center, funded by the National Oceanic and Atmospheric Administration (NOAA), are collaborating with the National Science Foundation to support a deep-sea expedition to the gulf to study ocean life that also depends on these economically important hydrocarbon fuels.

Scientists are riding a high-tech "inner space ship," the Johnson-Sea-Link research submersible, owned and operated by Harbor Branch Oceanographic Institution. Two scientists accompany a pilot and engineer on each dive in the four-person submarine. In the past 10 years, submersibles like the Johnson-Sea-Link have allowed scientists to explore and investigate the continental slope of the Gulf of Mexico, a new frontier for oil and gas companies and for discovering life in our oceans.

UNC Wilmington’s National Undersea Research Center conducts undersea research in waters off the Southeastern United States, including the Gulf of Mexico. Its expertise includes advanced diving and underwater laboratory Aquarius, undersea robots, and occupied submersibles (mini-submarines). For this project, UNCW is providing funds to lease the Johnson-Sea-Link submersible, and the National Science Foundation is funding the ship and scientists.

Join the expedition @Sea (www.at-sea.org) from July 2 to 19, 2001, to learn about the unique and lightless communities at the bottom of the Gulf of Mexico that are home to a variety of bizarre organisms like ancient giant tubeworms (they can live 250 years and grow to eight feet long) and the densest concentrations of bacteria found in our oceans. Importantly, the bacteria use chemical energy instead of sunlight in the perpetually dark deep sea where they form the base of the food chain in these incredibly productive communities. The bacteria feed on seeping hydrocarbons that contain sulfide and methane, which is usually deadly to terrestrial organisms. The bacteria live as dense mats on the seafloor or inside other organisms in a beneficial relationship called symbiosis.

The expedition is a collaborative effort among Drs. Samantha Joye (University of Georgia), Patricia Sobecky (Georgia Institute of Technology), Joseph Montoya (Georgia Institute of Technology) and Ian MacDonald (Texas A&M University). Primary sponsors are the National Science Foundation and UNCW’s National Undersea Research Center, a grant program of the National Oceanic and Atmospheric Administration (NOAA). The team will ride the submarine’s mothership, the research vessel Seward Johnson, to dive sites approximately 100 miles due south of Louisiana, where the continental shelf becomes steep at water depths of 500 to 1000 meters. The seafloor in this part of the Gulf of Mexico is characterized by mounds, ridges and valleys-- part of a vast salt deposit that forms a trap for rich petroleum reservoirs. Oil and gas harvesting platforms are increasingly common in the area as new technologies push drilling frontiers to deeper waters.

Salty brine pools are a unique feature of this petroleum basin. An ancient salt bed pushes upward through rock and sediments to form domes that fracture the seabed. Trapped fluids and gases sometimes rush up through the fissures to the seafloor surface causing blowouts and forming craters. Salt from the dome top mixes with warm seawater in the rock and sediment and may also flow up through fissures into the crater. These salty fluids, called brine, are four to five times denser than sea water and when cooled at the seafloor surface, form large pools in the craters.

During the expedition the science team will visit two brine pools-- one old and stable and the other young and active. The newer brine pool still has frequent eruptions of hot fluid and living communities are not abundant. In contrast, the older brine pool has been quiet and stable long enough for a dense community of deep sea mussels to develop around the pool’s edge. These mussels have specialized bacteria living in their gills that allow them to use dissolved methane as an energy source. Like shallow mussel beds and coral reefs, these beds are oases for a variety of sea life in the deep sea. Spectacular pictures are expected of the mussels living on the edge of these pools and associated animals.

Another exotic bottom feature of this area is a frozen substance known as gas hydrate that forms when methane mixes with water under the high pressures and cold temperatures of the deep sea. As long as high pressure is maintained, gas hydrates stay solid at temperatures of 8° C or more, which is well above the freezing point of water in air. Methane hydrates are found along continental margins around the world. Current estimates indicate that the amount of carbon contained in seafloor hydrates is two to three times greater than all other sources of fossil fuels on the planet combined, and is thus a potentially important energy source for the future. Like the brine pools, gas hydrates also support exotic forms of life. During Johnson-Sea-Link dives in 1997, scientists found a new species of polychaete worm living in shallow burrows of the ice. Of course, the worms had probably been there all along, but had simply escaped notice because scientists had never been able to take a close look. Scientists believe that the ice worms may also rely on bacteria living in the ice for food and thus represent a much more complex ecosystem than was previously known to exist. Expedition dives will visit the ice worm beds, plus new sites suspected to contain exposed gas hydrates that were discovered during oil company seismic surveys.

Expedition updates will be filed at @Sea (www.at-sea.org) throughout July as the expedition visits these new and exciting underwater realms.

For additional science information contact:

Andrew Shepard, Associate Director, UNCW’s National Undersea Research Center (NURC), sheparda@uncwil.edu, 910-962-2441.

For information on the web expedition, interviews, images, video, or to make contact with any of the scientists during the current cruise, contact:

Geoff Oldfather, Director of Public Relations, Harbor Branch Oceanographic Institution, oldfather@hboi.edu, 561.465.2400 ext. 206 or cell phone at 561-216-1458.