Climate Change in Antarctica's Desert Involves Breathing Microbes Too

The McMurdo Dry Valleys of Antarctica, a mostly ice-free area in the vast southern continent, are roughly the size of Mexico. Changes in the area's carbon dioxide flux are often thought to be caused entirely by geochemical movement in the soil, but a group of researchers from Arizona State University and Dartmouth College recently published their findings regarding soil organisms and the small but significant effect their respiration has on this very arid area. 

The researchers have found that soil water and microbes' respiration contribute to fluctuations in carbon dioxide in the valley, which is the world's coldest desert, according to Eurekalert. 

Already, climate change is creating wetter conditions in the dry valleys, changing the soil in this sensitive ecosystem. For their study, researchers examined the amount of carbon dioxide moving in and out of the soil-which shows how much soil organisms are releasing carbon dioxide when they breath - as well as geochemical processes in the soil. They conducted research to find out, in 24-hour cycles, whether organisms breathed differently in wet or dry soil, and whether the source of soil water mattered, Eurekalert said.

The study concluded that the types and amount of soil water changed the movement of geochemical carbon dioxide - in this case, carbon dioxide dissolves in water in the soil and is released later like a carbonated drink) -- and biological respiration of carbon dioxide.

"There's a debate about how much of the carbon dioxide flux in the Dry Valleys is biological because some people think it's all geochemical and the soil organisms don't contribute much. We showed the biology matters in a sometimes small but still significant way," says co-lead author Becky Ball, an assistant professor in Mathematical and Nature Sciences at ASU who studies soil nutrient cycling and soil biodiversity in polar and hot deserts, according to Eurekalert.

Co-lead author Ross Virginia, a professor of Environmental Studies and director of the Dickey Center's Institute of Arctic Studies at Dartmouth, says, according to Eurekalert: "The Dry Valleys are a very climate-sensitive system because it is so cold. A small increase in temperature can tip the ecosystem from frozen to melting, turning patches of desert into a wetland. That makes the soil a very different kind of habitat for the organisms living there, and it can change the cycling of carbon and the release of carbon dioxide. Under projected climate warming in the Dry Valleys, we can expect more water and a faster carbon cycle."

Follow Catherine at @TreesWhales