Let sleeping bugs lie

Dr. Megan Dillon

If you imagine the icy, desolate Arctic tundra, you might not picture living organisms hibernating underground. These creatures have been asleep for thousands of years, but now climate change might wake them up.

In addition to the slumbering creatures, the frozen Arctic soils store thirteen hundred trillion kilograms of carbon - that's about twice the amount already in the atmosphere. While the soils are frozen, the carbon stays where it belongs, underground. But as temperatures rise, that carbon can get released as CO 2 or methane greenhouse gases. As the soils release greenhouse gas, the temperatures rise even more in a climate change feedback loop.

People fighting climate change often overlook this enormous feedback loop because the organisms directly responsible for it are too small to see with the naked eye. Single-celled microorganisms wake up as the temperatures rise and start to eat the carbon that's been in the soil for milennia. The species that are awake while the soils are frozen eat and metabolize and release gas slowly. But the species that wake up when it gets hot eat, metabolize, and release gas fast. Right now, we don't know enough about the microorganisms to include them in climate models, which is a problem because we need those data to better predict climate scenarios in the next decades.

To provide the information about microorganisms and their digestive issues to climate scientists, our lab brought three foot long cores of soil from several sites across Alaska to Berkeley Lab.

We've hooked them up to many kinds of sensors to measure any differences in soil properties at the different locations. We're heating the cores up carefully to mimic natural thaw conditions and extracting the microorganisms, along with their DNA and the gas they release as the cores thaw. We're learning all sorts of things about the diversity and metabolism of these microscopic communities. Most importantly, we're trying to understand how to slow them down. If we can learn what lets the microorganisms keep sleeping, then scientists fighting climate change might be able to figure out how to keep more of that thirteen hundred trillion kilograms of carbon in the soil, where it belongs.