Sea Beds Hold Potential Fuel Source (Fall 1996)
Geology researchers from UNC-CH have confirmed what scientists have suspected for about ten years: that gas hydrates, a potential fuel source for the next century, exist in abundance in the ocean floor off the coast of the Carolinas. And since they exist there, says Professor of Geology Charles K. Paull, they probably exist in similar conditions in other parts of the ocean. Previous scientific studies have estimated that the amount of fossil-fuel carbon stored in existing gas hydrates may be twice the size of all known oil, gas, or coal deposits on earth.
Study of gas hydrates has never been easy. Once removed from the high pressures and low temperatures on the ocean bottom, the material deteriorates. In the past, scientists have had to study gas hydrates from an academic distance if they studied them at all.
But during their time spent on the international Ocean Drilling Project, Carolina researchers found a way to look at gas hydrates up close.
Last fall, Paull spent almost two months with students Wally Borowski and Nancy Black on board the 470-foot R/V Joides Resolution, taking sediment cores to study the presence of gas hydrates in the sea bottom. A specialized drill bit made it possible to raise pressurized samples of the sediment to the surface while preserving the sea-floor pressure, and thus the gas hydrates contained in the samples.
"People have seen gas hydrate disappear in front of their eyes on the decks of drill ships in the past," Paull says. "But if you're not prepared for it, what do you do?" With the drill, Paull and his students were able to get an idea, for the first time, just how much gas hydrate material was in the Blake Outer Ridge, 180 nautical miles off the coasts of Georgia and the Carolinas. As they drilled, they found as much gas hydrate as they expected and more, confirming scientific calculations that had never been tested.
But Paull cautions against assuming this means that gas hydrates will be a fuel source for the near future.
"I don't think anyone is saying that particular deposits that we were drilling in are an immediate energy source," he says, "but we need to figure out what the characteristics of this type of deposit are, and whether in the future it is a resource that can be extracted."
The very presence of such a large amount of gas hydrate gives geologists a new window on the earth's makeup and may even help predict changes in the atmosphere. Methane, which is the gas in most gas hydrates, makes up a fourth of the earth's greenhouse insulation. Paull says marine sediments may contain close to 10,000 times the amount of methane found in the atmosphere. These methane-rich gas hydrates, he says, may turn out to be one of the most important factors in regulating the earth's climate.
The research is part of Leg 164 of the Ocean Drilling Project, funded by the National Science Foundation and 19 countries.
—Marissa Melton