Scientists Tracking Rapid Thermokarsting As Permafrost Collapse Hits Alaskan Arctic - C&EN

[hatrack]

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No one is more keenly aware of how quickly the environment is changing than the scientists at Toolik Field Station, the National Science Foundation’s Arctic long-term ecological research site, where Bret-Harte is the associate scientific director. Since the camp was established in the 1970s, researchers have returned summer after summer to conduct long-term studies of the plants, lakes, rivers, and wildlife. They see firsthand that in the carefully balanced environment of Alaska’s North Slope, small changes can have major consequences.

Now, a large group of scientists are collaborating to understand how the consequences of a warmer Arctic could impact its landscape and feed back into global warming. With a grant from NSF, they are studying the mechanics of thermokarsts, or features created when permafrost, or soil that has been frozen for years, melts, then collapses like a soufflé. Each scientist brings a different kind of expertise that can help create a complete picture of how a thermokarst changes the surrounding environment. "The Arctic is a place where everything is about the minutest change in energy balance,” says William (Breck) Bowden, an aquatic ecologist at the University of Vermont, who has been coming to Toolik for more than 20 years.

Just how delicate is that balance? Consider a set of tire tracks visible in the tundra near a pump station off the Dalton Highway on Alaska’s North Slope. The tracks look freshly made, but are actually a relic from the 1940s, when a single vehicle passed over the surface of the tundra. All it takes is the weight and friction of the truck to expose the soil, making a small change to the albedo, or the amount of light being reflected away from the ground’s surface, and the area begins to melt. “And as it continues to melt, a new community of vegetation starts to grow there, and now we have a scar,” Bowden says.

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After flying up about 25 miles, they came to a water track that was pouring tons of sediment into the Toolik River. As they followed the stream, they saw a large rip in the tundra: a freshly formed thermokarst. “We flew over it a couple of times and were just amazed by this gash,” Gooseff recalls. The helicopter set down, and the pair saw that a huge gulley had formed. The hole in the ground was so deep that Bowden, who is at least 6’2”, was fully immersed as he stood on a small carpet of tundra that had surfed to the bottom. As the earth wrung itself out, so much water was released that a small waterfall had even formed. The scientists believe the ground had collapsed somewhere from hours up to a few days before they stumbled upon it. Their discovery provided an amazing opportunity to study the feature in depth from its genesis. The vast collaboration around thermokarsts that subsequently came together has several broad objectives. The researchers want to know how and why thermokarsts occur and to generate a predictive model that could help identify environments where a failure is more likely.

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http://pubs.acs.org/cen/science/87/8733sci1.html

[Chemisse]

1. Sadly, our global warming is keeping scientists busy