New lakes in Alaska release bubbles full of methane

The methane bubbles emerging from these newly formed lakes are caused by microbial activity.

The methane bubbles emerging from these newly formed lakes are caused by microbial activity.

New lakes are emerging in Alaska due to thawing permafrost and the release of methane, a greenhouse gas, into the atmosphere.

Big Trail Lake in Fairbanks, Alaska is one of those “thermokarst lakes” that has sprung up over the past 50 years and is constantly spouting methane-filled bubbles, according to a NASA blog post.

Permafrost is ground that remains frozen all year round. In Alaska, the permafrost also contains huge wedges of ice locked into the ground. When the ice melts, the ground surface collapses and forms a water-filled sinkhole, creating a thermokarst lake.

Katey Walter Anthony is a researcher collaborating with NASA’s Arctic Boreal Vulnerability Experiment (ABoVE), a large-scale study of environmental change and its implications for social-ecological systems. She has studied the formation of thermokarst lakes and how the process influences Earth’s climate change.

“Lakes like Big Trail are new, they’re young, and they’re important because these lakes are what’s going to happen in the future,” she explained.

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The methane bubbles emerging from these newly formed lakes are caused by microbial activity. Microbes digest dead plants and organic matter from previously frozen soil, producing carbon dioxide and methane. Thawing permafrost can also form chimneys under the lake that allow gases like methane to escape from where they were trapped underground.

“At Big Trail Lake, it’s like opening your freezer door for the first time and giving all the food in your freezer to the germs to decompose. As they break it down, they spit out methane, says Walter Anthony.

A simple way to test if the lake is emitting old methane is to light a match near the gas sample taken from the lake. As a flammable gas, it will ignite easily until supply is maintained. Scientists use field measurements, collected samples and airborne radar data to estimate how much methane these lakes are releasing over a wide area.

Methane is the main contributor to the formation of ground-level ozone, a dangerous air pollutant. A potent greenhouse gas, it is 80 times more potent for warming than carbon dioxide over a 20-year period, according to a UNEP report. Although it has a much shorter atmospheric lifetime than carbon dioxide, methane has been responsible for 30% of the increase in global temperatures since the industrial revolution. In fact, it’s proliferating faster today than at any time since record keeping began in the 1980s, according to a study by the US National Oceanic and Atmospheric Administration.

Recently formed in Alaska, these types of lakes are abundant in the Arctic. Some arctic lakes are hundreds or thousands of years old and the microbes in them no longer have permafrost organic matter to decompose. As a result, these older lakes do not release as much methane as newer ones in Alaska, such as Big Trail Lake.

“So what’s of concern for the future, when you think about permafrost carbon feedback, is the areas that have just thawed,” says Walter Anthony.

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