Feb. 10, 2000 After 14 grueling days on a drilling rig off the coast of Japan, INEEL microbiologist Mark Delwiche brought home his prize - two coolers full of frozen logs of mud. These core samples harbor stubbornly hardy methane-producing microorganisms that may eventually provide answers to the world's future energy worries.
Mark Delwiche is part of a team of microbiologists at the Department of Energy's Idaho National Engineering and Environmental Laboratory pursuing fundamental research to learn the secrets of methane-producing microorganisms known as methanogens. Through a cooperative research effort with the Japanese Petroleum Exploration Company, Delwiche helped crew the drilling rig H.G. Hulme, Jr. in late November to secure deep subsurface core samples that will form the basis of his research for the year.
The crew drilled into a marine shelf region 60 kilometers off Japan's Omae Zaki peninsula over the Nankai Trough through 950 meters of water. The area is known to contain large amounts of gas hydrate - methane gas molecules trapped in lattices of ice - and may also contain extractable natural gas in formations considerably deeper than the hydrate deposits. For the Japanese, the two-fold purpose of the expedition was to explore the possibilities of harvesting the fuel.
Delwiche, who has collaborated with the Japanese Petroleum Exploration Company for the past four years, was one of only two western researchers invited to participate in what has come to be known as the "MITI Research Hole." The culmination of several years of planning, the expedition is part of a general effort by the Japanese Ministry of International Trade and Industry (MITI) to increase Japanese expertise in the fuel exploration arena and to contribute to the assessment of Japanese fuel resources.
"It's was exciting to be in such a focused group of scientists like that. This is their life. The discussions in the small hours of the night, the back of the envelope calculations, the sketches and speculations were beyond compare. This is where the rubber meets the road," said Delwiche. Read his daily dispatches from the rig at http://inelext1.inel.gov/science/feature.nsf/ineel/delwiche.
The DOE is interested in methanogens--microorganisms that produce methane--for several reasons. The estimated volume of methane gas presently trapped in ocean floor and continental sediments is generally accepted to be as much as twice the known reserves of recoverable and non-recoverable fossil fuels, though the actual numbers are always subject to change as the scientific knowledge base expands. The massive pockets of methane could become an important energy resource as fossil fuel reserves are eventually exhausted. Additionally, methane gas is potentially a major contributor to global warming. So for both environmental and energy reasons, the DOE has an interest in these deep sea microscopic communities. The INEEL team hopes to learn where methanogens prefer to live and why, and begin to understand how fast they produce methane.
Methanogens live in a remarkably hostile world - frigid, high-pressure environments deep in the ocean floor or continental subsurface. Theirs is the domain of the deprived - with little food trickling down through the soil and incredibly cramped living space in the pores of the sediments. They are virtually struggling for survival - focused more on simply maintaining their ability to metabolize food rather than reproduction.
Delwiche's objective was to obtain samples, and transport them intact, frozen and uncontaminated, back to the lab for analysis. He collected samples of sea water and drilling fluids as controls to verify that his samples were not contaminated during the drilling process. Little is known about methanogens and methane hydrates, despite the fact that oil and gas companies have been aware of their existence for decades. Deep subsurface samples such as those collected on this expedition are very difficult and expensive to obtain and are a constant limiting factor in research.
With core samples from 1109 to 1273 meters below the sea surface, the INEEL team will learn about the vertical distribution of the methanogen community. Researchers hope to answer two questions through their work. Does the presence of methane - the microbe's waste byproduct - affect further production of methane? Does the presence of the microbes themselves affect the rate of hydrate formation?
One of the first steps will be to count the numbers of microorganisms in the samples. This will give researchers insight into what substrates and temperatures the microorganisms prefer. Methanogens appear to be capable of surviving in very extreme conditions, but how much methane gas and how fast they produce it still elude researchers. "We still don't fully understand what is important for the production of methane by these microorganisms," said INEEL microbiologist Rick Colwell.
This research is supported by DOE National Energy Technology Laboratory, and Japanese Petroleum Exploration Company (JAPEX), and through INEEL discretionary research funds. The INEEL is operated for the U.S. Department of Energy by Bechtel BWXT Idaho, LLC.
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