What controls the stabilization of organic carbon in soils?

The exchange of carbon between the land surface and the atmosphere is one of the largest fluxes in the global carbon cycle. Soils can be sources or sinks of carbon and one of the most important feedbacks associated with future global change will likely be the response of soil organic matter to warming. We are therefore studying the processes by which organic carbon is stabilized in soils. As part of this work, we are developing and testing numerical models against observed profiles of the concentration and isotopic composition of soil organic carbon.