Nearly half of the organic carbon stored in soil around the world is contained in Arctic permafrost, which has experienced rapid melting, and that organic material could be converted to greenhouse gases that would exacerbate global warming.

When permafrost thaws, microbial consumption of those carbon reserves produces carbon dioxide -- much of which eventually winds up in the atmosphere, but scientists have been unsure of just how the system works.

A new study published this week in Nature Communicationsoutlines the mechanisms and points to the importance of both sunlight and the right microbial community as keys to converting permafrost carbon to CO₂. The research was supported by the U.S. National Science Foundation and the Department of Energy.

The research team from Oregon State and the University of Michigan was able to identify compounds that the microbes prefer using high-resolution chemistry and genetic approaches. They found that sunlight makes permafrost soils tastier for microbes because it converts it to the same kinds of carbon they already like to eat  the carbon they are adapted to metabolize.