Posts Tagged ‘methane’

Earthquakes release methane from methane hydrates

July 29, 2013

“Natural” release of methane from methane hydrates by earthquakes is more common and more significant than has been thought or accounted for in climate models.

The inescapable conclusion is that effects  being attributed by the demonisation of carbon to man made carbon dioxide emissions (even if real) may well be partly due to the natural release of such methane.  The global temperature pause for the last 17 years or so and the clear but small decline in global temperatures for the last 5 years is quite clear. At the same time emissions from fossil fuel combustion have been steadily increasing. These are a clear indication that the supposed linkage between carbon dioxide concentration and man-made carbon dioxide emissions on climate is very suspect if not completely broken.

It is also becoming increasingly clear that climate models – even though very complicated – are far too simplistic and just don’t (can’t) take all factors into account. Clouds, aerosols, particulates, solar effects, lunar cycle effects through the tides, ocean cycles and now earthquakes are all poorly understood and largely ignored in climate models. There is far more in the realms of the unknown about the climate than is known. We don’t even know what we don’t know.

David Fischer, José M. Mogollón, Michael Strasser, Thomas Pape, Gerhard Bohrmann, Noemi Fekete, Volkhard Spiess & Sabine Kasten, Subduction zone earthquake as potential trigger of submarine hydrocarbon seepage, Nature Geoscience (2013) doi:10.1038/ngeo1886

Here we present geochemical analyses of sediment cores retrieved from the convergent margin off Pakistan. We find that a substantial increase in the upward flux of gas occurred within a few decades of a Mw 8.1 earthquake in 1945—the strongest earthquake reported for the Arabian Sea. Our seismic reflection data suggest that co-seismic shaking fractured gas-hydrate-bearing sediments, creating pathways for the free gas to migrate from a shallow reservoir within the gas hydrate stability zone into the water column. We conservatively estimate that 3.26×108 mol of methane have been discharged from the seep site since the earthquake. We therefore suggest that hydrocarbon seepage triggered by earthquakes needs to be considered in local and global carbon budgets at active continental margins.

New York Times:

Dr. Fischer and his colleagues analyzed sediment cores taken in 2007 from two locations in the northern Arabian Sea where hydrates were present and seepage was occurring. They found chemical signatures in the cores suggesting that the methane flow greatly increased sometime in the mid-20th century. Looking through seismic records, Dr. Fischer found that a magnitude 8.1 quake occurred in the area in 1945. The quake, which was centered less than 15 miles from where the cores were taken, and a resulting tsunami, killed up to 4,000 people.

The conclusion was inescapable, Dr. Fischer said. “The quake broke open gas-hydrate sediments and the free gas underneath migrated to the surface.” The hydrates themselves did not dissolve. “They remain there,” he said.

Dr. Fischer said the researchers chose the core locations in the Arabian Sea because they wanted to get a better understanding of how methane seepage was related to tectonics, and the area is in an active zone where one of the earth’s tectonic plates slides beneath another. But they were not thinking about the effect of individual earthquakes, and his discovery of the 1945 quake in the records “was probably a moment I’ll never forget,” he said.

The upward flow of methane is continuing today, and the researchers do not know when it might stop. All told, they estimate that nearly 10 million cubic yards of methane have been released from the core sites over the years. But that is a conservative figure, Dr. Fischer said, because immediately following the quake the flow would have been much higher.


Japanese test confirms successsful extraction of gas from deep-sea methane hydrate

March 13, 2013

Methane hydrates represent the largest source of hydrocarbons in the earth’s crust.

“The worldwide amounts of carbon bound in gas hydrates is conservatively estimated to total twice the amount of carbon to be found in all known fossil fuels on Earth”.

JOGMEC has put out a press release:

Japan Oil, Gas and Metals National Corporation which has been conducting preparation works for the first offshore production test off the coasts of Atsumi and Shima peninsulas, started a flow test applying the depressurization method and confirmed production of methane gas estimated from methane hydrate layers on March 12, 2013.
JOGMEC will start analyzing data while it continues the flow test.

Methane hydrate receives attention as one of the unconventional gas resources in the future.
During the period from FY2001 to FY2008, which is Phase 1 of the “Japan’s Methane Hydrate R&D Program”, seismic surveys and exploitation drillings were conducted at the eastern Nankai trough, off the coast from Shizuoka-pref. to Wakayama-pref., as the model area, where a considerable amount of methane hydrate deposits is confirmed.
In Phase 2 of the Program starting from FY2009, aiming to develop a technology to extract natural gas through dissociation of methane hydrate, this is the first offshore test ever conducted. The first offshore production test is planned over a span of two years. In February and March last year, the preparatory works including drilling a production well and two monitoring wells were conducted. From June to July, the pressured core samples were acquired from methane hydrate layers. In this operation, a flow test through dissociation of methane hydrate is conducted after the preparatory works including drilling and installing equipments for the flow test.

Deposits of methane hydrates have been reported in marine sediments in the Nankai Trough off the Pacific coast of central Japan, where the water depth is more than 500 meters. Some estimates indicate that the reserves of methane hydrate correspond to a 100-year supply of natural gas for Japan, making it an important potential source of energy. The Japan National Oil Corporation (JNOC) began research work on methane hydrates in 1995, and JOGMEC has overseen the project since the JNOC’s restructuring. An international joint research team including Japan has obtained successful results in experimental production of methane gas by injecting hot water into a borehole in the Mackenzie Delta in the arctic region of Canada.

With shale gas and shale oil adding to the known reserves of oil and gas and now with the potential exploitation of deep-sea methane hydrates, “peak-oil” and “peak-gas” would seem to have been postponed by a millenium.


Dinosaur flatulence caused global warming

May 7, 2012

Oh dear!

It sounds like a calculation a 10 year old could have made – given a few assumptions.

And this is what passes for peer-reviewed science ……… and for science reporting.

BBC Nature:

Giant dinosaurs could have warmed the planet with their flatulence, say researchers.

British scientists have calculated the methane output of sauropods, including the species known as Brontosaurus.

By scaling up the digestive wind of cows, they estimate that the population of dinosaurs – as a whole – produced 520 million tonnes of gas annually.

They suggest the gas could have been a key factor in the warm climate 150 million years ago. 


Methane from BP oil spill has vanished – presumed digested by microbes

January 9, 2011
Molecule of methane.

methane molecule: Image via Wikipedia

A new paper online in Science:

Science DOI: 10.1126/science.1199697 A Persistent Oxygen Anomaly Reveals the Fate of Spilled Methane in the Deep Gulf of Mexico, by John D. Kessler, David L. Valentine, Molly C. Redmond, Mengran Du, Eric W. Chan, Stephanie D. Mendes, Erik W. Quiroz, Christie J. Villanueva, Stephani S. Shusta, Lindsay M. Werra, Shari A. Yvon-Lewis and Thomas C. Weber

It adds to the growing body of evidence that the oceans with the help of microbes are much more resilient than they have been assumed to be.

As Science News puts it:

Methane, the predominant hydrocarbon produced by the BP blowout last year, has all but vanished from Gulf of Mexico waters, a new study reports — presumably eaten up by marine bacteria. That hadn’t been expected to happen for years.

Two-thirds of the hydrocarbons released by the BP accident were forms of natural gas: largely methane, ethane and propane. While Gulf microbes quickly began devouring the larger gas molecules, they initially left tiny methane — which accounted for an estimated 87.5 percent of the gas initially emitted — largely untouched.

Some of the authors of the new paper had reported in the Oct. 8Science finding almost no microbial breakdown of BP methane in June, about a month and a half into the 83-day gusher.

Rates of biodegradation in subsea plumes, where this gas had been accumulating, “indicated methane would persist for many, many years, if not almost a decade,” observes John Kessler, a chemical oceanographer at Texas A&M University in College Station and an author of that earlier report.

To begin quantifying just how slowly that breakdown was proceeding, he and his colleagues returned to the Gulf for three research cruises between August 18 and October 4. Their sampling at more than 200 sites turned up no BP methane. In fact, concentrations of the gas in seawater throughout the spill zone were lower than typical background concentrations for the Gulf, these researchers report online January 6 in Science.

“We were caught off guard,” Kessler says. “But that highlights the beauty of the scientific process. You put together hypotheses based on the information at hand and test them. And whether we’re right or wrong, at the end of the day we’ll have learned something new about the system.”

The new paper’s conclusions “are quite consistent with what we’ve seen,” says microbial ecologist Terry Hazen of Lawrence Berkeley National Laboratory in California. On August 24, his team was the first to report online in Science that BP oil plumes had disappeared.


Microbes consume methane 10 to 100 times faster than thought

October 20, 2010


Structure of the methane molecule: the simples...

methane: Image via Wikipedia


A follow up to my previous post:

From EurekAlert:

Microbes may consume far more oil-spill waste than earlier thought

Microbes living at the bottom of the Gulf of Mexico may consume far more of the gaseous waste from the Deepwater Horizon oil spill than previously thought, according to research carried out within 100 miles of the spill site.

A paper on that research, conducted before the Deepwater Horizon rig exploded six months ago today, will appear in a forthcoming issue of the journal Deep-Sea Research II. It describes the anaerobic oxidation of methane, a key component of the Gulf oil spill, by microbes living in seafloor brine pools.

“Because of the ample oil and gas reserves under the Gulf of Mexico, slow seepage is a natural part of the ecosystem,” says Peter R. Girguis, associate professor of organismic and evolutionary biology at Harvard University. “Entire communities have arisen on the seafloor that depend on these seeps. Our analysis shows that within these communities, some microbes consume methane 10 to 100 times faster than we’ve previously realized.”

Girguis is quick to note that methane is just part of what spilled from the ruptured Deepwater Horizon well for three months earlier this year, and that the rate at which methane spewed from the damaged well far exceeds the flow that microbes would ordinarily encounter in the Gulf.

Key to the work by Girguis, Harvard research scientist Scott D. Wankel, and their colleagues was the ability to use on-site mass spectrometry to obtain direct, accurate measurements of seafloor methane. It’s been difficult to make such measurements because most tools don’t work accurately 5,000 to 7,000 feet below the surface, where pressures can reach roughly 220 atmospheres.

Using this new technique, the scientists were able to ascertain methane concentrations in brine pools surrounding gas seeps at the bottom of the Gulf — which were extremely high — as well as in the water column above the pools. Combining this data with measurements of microbial activity, they were able to extrapolate just how quickly the microbes were consuming the methane.

“In fact, we observed oxidation of methane by these microbes at the highest rates ever recorded in seawater,” Girguis says.

Methane is a greenhouse gas, up to 60 times more potent than carbon dioxide. Gigatons of the volatile gas are produced in seafloor sediments, above and beyond that generated by gas seeps that pockmark the floor of the Gulf of Mexico and other bodies of water. But, Girguis says, somewhere between the seafloor and the sea’s surface, much of the methane vanishes.

“We found that concentrations of methane in brine pools are tremendously high: five to six orders of magnitude higher than in the water column above,” Girguis says. “Mass spectrometry has given us a window on both the amount of methane diffusing into the water column and how much of this methane is consumed through anaerobic oxidation by microbes within the brine pool. It appears the microbes consume much of the methane, and the rest dissipates over time into the water column.”

A study published in the journal Science in August detailed a bacterial species reportedly able to degrade oil anaerobically in the Gulf. But a subsequent Science paper contended that these microbes mainly digested gases like methane, propane, ethane, and butane, not oil. The Deep-Sea Research II paper adds to scientists’ growing understanding of these species’ ability to degrade the byproducts of the Deepwater Horizon spill.

Girguis and Wankel’s co-authors are Samantha B. Joye and Vladimir A. Samarkin of the University of Georgia, Sunita R. Shah of the U.S. Naval Research Laboratory, Gernot Friederich of the Monterey Bay Aquarium Research Institute, and John Melas-Kyriazi of Stanford University.

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