News Release

INEEL microbiologist joins Japanese on expedition to tap marine-methane deposits

Peer-Reviewed Publication

DOE/Idaho National Laboratory

After fourteen 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 purpose of the expedition was to explore the possibilities of harvesting the fuel.

Delwiche spent the first couple of balmy 75-degree days on the drilling rig "on call" and ready to take samples as the crew positioned the semi-submersible drilling rig and started to core into the ocean floor. But a couple of experimental coring techniques failed, delaying the process and contributing to a sense of urgency and anticipation among the crew. Delwiche, who e-mailed updates of his progress to the lab, waxed poetic at the range of birds he was able to observe from the rig and references to Moby Dick started to show up in his messages.

By day four, the crew resorted to conventional coring techniques and the real work began -- sometimes four hours on, four hours off -- taking sample after sample, processing one meter at a time. Time passed more quickly then and the light was rarely on in the cabin Delwiche shared with three other crew members. "We were all in sleep like dogs mode, lots of short naps, work when the core is up," said Delwiche. His dirty laundry disappeared and reappeared clean, and food came round the clock.

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.

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.

These methanogens live in a remarkably hostile world -- frigid, anaerobic, high-pressure environments deep in the ocean floor or continental subsurface. Theirs is the domain of the deprived -- with little food trickling down from the surface 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 living near 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.

"The sampling process is one of the most important parts of this kind of research," said co-sponsor Hugh Guthrie, senior management and technical advisor for DOE's National Energy Technology Laboratory. "Mark's participation in this project is extremely important. Work being done by the microbiologists at the INEEL is crucial to determining if significant amounts of the methane is biogenic in origin and whether or not this resource would be renewable."

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? How does the distribution of the microbes determine the distribution of the hydrates?

As in previous work, researchers will extract methanogens from sediment samples and culture them in the lab. Delwiche, who has been designing high-pressure systems since 1994, has created a small two-liter bioreactor with a temperature gradient that simulates on a small scale the natural conditions of the ocean floor. The ongoing challenge in refining the bioreactor design is creating conditions that accurately reflect real life in the oceanic subsurface. "A 10-degree temperature drop might correlate to as much as 300 meters in real life, and we certainly can't make a 400-meter-long bioreactor," said Delwiche.

One of the first steps will be to count the numbers of microorganisms in the samples. This will give researchers insight into places in the sediment where microbial activity is high. 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.

Researchers want to understand the link between the microbes and methane hydrates to determine whether hydrates would be a renewable resource. Unlike fossil fuel deposits, marine methane hydrate deposits are relatively dynamic, changing all the time as pressures and temperatures change within the system. "Those pockets of methane are probably a much more fragile resource than we might hope for," said Colwell.

Methanogens may also produce methane too slowly to make hydrates truly renewable. "It's questionable whether they would be a 'renewable' energy source. It may take literally thousands of years to replace any methane that might be harvested, not tens or hundreds of years," said Delwiche.

When asked if methane hydrates will eventually become an economically viable energy resource, both Colwell and Delwiche pause and then shrug their shoulders. "The time will come when we will need to know whether or not we can access this resource," said Delwiche. "This research will help us make those decisions."

Being back on a drilling rig was like old times for Delwiche, who spent ten years doing such work earlier in his career. But round-the-clock work, cramped quarters with no privacy and only a tenuous connection to the outside world can wear thin. "I never got good at feeling like the environment on a drilling rig was very homey," jokes Delwiche.

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Read Mark Delwiche's dispatches from the rig at inelext1.inel.gov/science/feature.nsf/ineel/delwiche.

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.

Technical Contact: Mark Delwiche, (208) 526-1870, or mde1@inel.gov.
Media Contact: Deborah Hill, (208) 526-4723, dahill@inel.gov or John Walsh, (208) 526-8646, jhw@inel.gov.
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