University of Alaska Fairbanks studies methane gas build up in Alaskan ice
FAIRBANKS, Alaska (KTVF) - Researchers at the University of Alaska Fairbanks (UAF) are studying methane gas that builds up under the ice.
According to Katey Walter Anthony, a Research Professor for the University of Alaska Fairbanks, methane build up is especially common in Alaskan lakes.
“In Alaska, almost every lake is releasing methane,” Walter Anthony explained. “In most lakes, the methane is coming from dead plant and animal remains that are decaying in the bottom of the lake sediments. [But] there’s another type of methane that’s more rare, and that is methane that has been trapped in or beneath permafrost for longer periods of time. A lot of times it’s associated with coal - coal bed methane - or it could be natural gas associated with petroleum, or even just microbial decomposition of really ancient sediments in the subsurface.”
These gasses lie trapped in permafrost which slows its rise to the surface. However, the eventual build-up in pressure could possibly cause the gas to become volatile.
“The movement of that gas up into the atmosphere gets impeded by permafrost, because permafrost is less permeable,” Walter Anthony elaborated. “It’s not a perfect seal but it certainly slows down gas that wants to make its way to the surface. So if a lake forms, or you have water running in a river, that surface water has heat in it and it causes the ground to thaw. Then if you’ve got gas trapped underneath, when that thaw bulb intersects where the gas is, the gas becomes unstable and there’s a migration pathway that opens up. If there’s enough pressure that’s built up, it could conceivably lead to an explosion.”
Walter Anthony continued, “ What we see are gigantic pockmarks in the bottoms of lakes that appear to be bigger than the current rate of emission is. So that tells us that likely in the past, the emission was higher. A lot of times we see sediment that has been ejected out of these holes, these pockmarks. So again, it suggests that it’s conceivable that there could have been an explosion.”
However, the possible combustion may not actually be the largest source of danger out on the ice according to Walter Anthony. “The biggest dangers associated with them is that the rapid rates of gas bubbling prevents the ice from freezing, and so you can have large open holes in lakes that would swallow a vehicle, or dog sled team, or snow machine if they were to cross over those holes - and a lot of times, especially in the heart of winter, those holes are masked by a very thin layer of frozen slush or snow that’s not enough to hold anybody up.”
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