Racing To Unlock The Secrets Of The Ocean Floor

The Minerals Management Service (MMS) of the U.S. Department of the Interior has provided $4.85 million for the four-year Deep Gulf of Mexico Benthos (DGoMB) project. DGoMB involves faculty and students from four Texas A&M colleges and more than a dozen other institutions around the world in studying the structure and functions of deepsea life forms.

"The MMS is concerned about how things that live on or in the bottom of the Gulf might be affected by offshore oil production," said Gilbert T. Rowe, Texas A&M oceanography professor and manager of DGoMB. "Oil companies have been drilling on the continental shelf of the Gulf for the past 50 years; indeed, that area is a city of production rigs. But now that technology makes possible drilling in deep water, everyone is concerned about the environmental impact of exploration and production on the continental slope and the greater depths beyond.

"This type of work is usually undertaken by private consulting companies," he observed. "So we're thrilled that the MMS chose Texas A&M as the lead organization in this large effort. We feel that environmental impact research like this should be done by universities. Educational institutions are the proper societal guardians of such information, and projects like this also provide needed research training for students."

To reach the Gulf bottom, Rowe and his team use a benthic lander, a 10-foot-tall, one-ton device that functions somewhat like the astronauts' lunar lander. The benthic lander is neutrally buoyant. Anchor weights cause it to descend freely down to the ocean bottom, where it can stay for two days. Once there, it uses sensors to analyze the seawater for nutrients and oxygen and employs time lapse cameras to record animal life activity.

The program also employs an acoustic Doppler device to measure currents and baited traps to capture elusive animal specimens.

"There are a lot of bizarre fauna down there," Rowe said. "For example, there are creatures that act like buzzards, cleaning up the ecosystem. One question is how they find dead carcasses in such a clean, dark cold featureless landscape.

"These scavengers include a species of shrimp-like crustaceans that is impossible to catch by any normal means, so we don't even have a reliable estimate of how many of them there are."

DGoMB focuses on the ecology of organisms on the deepsea floor in the deepest reaches of the Gulf of Mexico. Field work will cover the entire northern Gulf continental slope from depths of 200 meters to greater than 3,000 meters (about 9,000 feet) seaward from the base of the Sigsbee and Florida escarpments. All told, researchers will spend more than 100 days at sea on the Texas A&M research vessel GYRE, out of Galveston.

"We spent last May and June trawling the Gulf bottom and coring sea bottom sediments," Rowe said. "We came back to College Station with a huge data set and specimens including everything from bacteria to fish. Other universities are assisting us to quantify the different groups of diverse organisms and catalog the specimens. For example, the University of Washington is handling bacteria, the Memorial University of Newfoundland is mapping, and the Marine Science Institute of the University of Texas is assisting with invertebrate analysis.

"In addition, we have consultants all over the world working on the taxonomy of all the new species we're bringing up," he observed. "Our next cruise, beginning this June, will collect data to try to explain the dynamic processes that enable organisms to live where they do."

Future Gulf research will also feature increased cooperation with Mexico, since that country's exclusive economic zone (EEZ) in the Gulf of Mexico begins where that of the U.S. ends, at 26 degrees North latitude.

Rowe and his team have designed DGoMB activities with an eye to gaining better abilities to predict variations in the structure of animals in relation to where they live: depths, geographic location, time, water mass and human-induced perturbations. They're measuring such animal community characteristics as diversity, taxonomic compositions, biomass, abundance and mean size of individuals in different taxonomic groups.

The upcoming cruise will seek data on respiration and growth of the organisms in an effort to validate researchers' dynamic simulation models built to predict how communities will vary over time in response to perturbations by human activities in the Gulf.

"The highest density of bottom-dwelling life forms has turned out to be in the Mississippi Canyon, a favorite area for oil exploration and drilling," Rowe said. "In this area, the Mississippi River drops its load of mud, and turbidity forces it into a broad canyon, where it appears to flow down the continental slope, at depths of from several hundred feet to more than several miles below the sea surface. We'll be examining community processes at a mid-point in this canyon, as well as in the DeSoto Canyon, another high density area, and in two more areas in very deep water."

"We're also helping to clean up the Gulf," he continued. "Every trawl brings up a surprising amount of trash that has been dumped overboard from ships. We always capture beer cans along with our specimens."