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Tuesday, September 09, 2014

Geological Wonders: Natural Methane Seeps Off U.S. Atlantic Coast

Reported as "Widespread methane leakage from the sea floor on the northern US Atlantic margin", then noted here:
Researchers have discovered 570 plumes of methane percolating up from the sea floor off the eastern coast of the United States, a surprisingly high number of seeps in a relatively quiescent part of the ocean. The seeps suggest that methane’s contribution to climate change has been underestimated in some models. And because most of the seeps lie at depths where small changes in temperature could be releasing the methane, it is possible that climate change itself could be playing a role in turning some of them on.
For a handful of the seeps, the researchers were able to take pictures with a remotely operated submersible. They found carbonate rocks associated with the seeps that would have taken several thousand years to form. But some of the seeps are shallow—and are at the critical depth where hydrates fall apart—so they could be sensitive to rising ocean temperatures on much shorter time scales, says Carolyn Ruppel, a co-author of the new study and chief of the gas hydrates project at the U.S. Geological Survey in Woods Hole, Massachusetts. “There are reasons to believe that some of the present seepage has been triggered by changes in oceanographic conditions,” she says.

Proving that climate change is directly responsible could be difficult, Berndt says. In January, he and colleagues published a study in Science on methane seeps in the Arctic Ocean off the coast of the island of Svalbard, where temperature changes are occurring more rapidly. Berndt found evidence that the seeps there had existed for at least 3000 years and saw no evidence that the ocean sediments had been heating up—and releasing methane—on the decades-long timescales associated with climate change. At the very least, though, he says, the Atlantic Ocean study shows that ocean and climate modelers should start to incorporate methane inputs from many more types of seafloor terrains around the world. “We have this extra source here,” he says. “Not much attention has been paid to it.” (emphasis added)
Just about anyone familiar with coal fields and oil and gas geology is going to tell you that there are pockets of methane beneath the earth's surface, some of which finds its way to the surface - sometimes in unusual ways. For example, there is the Flaming Geyser around which a Washington State Park is formed:
The park is so named for a flame which burns through a concrete basin, fueled by a methane gas pocket 1,000 feet below the surface. When the pocket was discovered by prospective coal miners in the early 1900s, the test hole hit gas and saltwater, shooting water and flames 25 feet into the air. The same methane pocket seeps gas through a mud hole to create the "Bubbling Geyser" nearby. Both "geysers" can be found along a short hike.
Nor is this unique - geysers in Yellowstone National Park release small amounts of various gases:
Most geyser basins are either acidic or alkaline, and in some, like Norris, acidic and alkaline springs flow side by side. Some of the thermal features emit strong or obnoxious smells and even deadly odoriess gases. These gases, released at the surface after the pressure lowers, include carbon dioxide, hydrogen sulfide, methane, hydrogen, oxygen, nitrogen, ammonia, argon, radon, as well as other noble gases such as helium, neon, krypton, and xenon.
Even the famed NYTimes reports on the issue of coal mines and methane, as in this article:
Coal mines will always have methane, often in explosive concentrations, geologists and engineers say.
The gas, like coal, is a molecule made of hydrogen and carbon, and it is produced from the same raw material as coal, ancient piles of biological material, by the same processes. Much of the natural gas sold in the United States is drawn from coal seams.

In undisturbed coal deposits, the methane is loosely attached to the coal molecules when the deposit is under pressure; when the area is opened up by miners, the pressure is reduced and the methane bubbles out.

“Methane is ubiquitous on the coal mines,” said Neville A.H. Holt, a chemical engineer at the Electric Power Research Institute, in Palo Alto, Calif.
Methane feeding bacteria
In short, down under us in the ground beneath our feet and under the seas, the same raw materials that make coal and methane exist - so there should be no surprise that some of the gas thus create might find to reach the surface.

As stated here:
It wriggles up through fissures in Earth’s crust. It emanates from landfills. It is the primary component of cow burps and natural gas. This colorless, odorless gas is methane, and it is one of Earth’s most abundant—and, in some ways, most elusive—energy resources.

Produced primarily by living creatures breaking down organic matter, methane is the largest hydrocarbon source on Earth, making it the most common member of the chemical family that includes such fuels as petroleum and propane. Despite its abundance, however, methane remains difficult to use as a fuel because it is a gas under normal conditions, making it notoriously hard to store or transport.

Asserting that these seeps are due to climate change shouldn't be too surprising, either, since that's how the materials got under the sea in the first place.

We do not live on a planet with a static climate.

If you need proof of that, I suggest, once again, you go look at the history of glaciers.

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