Globally, soils store the largest part of the actively-cycled terrestrial carbon stock. However, long-term soil carbon storage can be reversed by changes in environmental conditions, especially moisture availability and temperature.

Understanding the ways soil carbon is protected by interactions with minerals in soil, and how sensitive these stabilizing processes are to environmental conditions, may help improve prediction and quantification of carbon feedbacks from soils to the atmosphere.

Using soils collected across the large spatial scale of the National Ecological Observatory Network, new research suggests that the ways soil carbon binds to mineral surfaces at the nanometer scale influences whether soil carbon is more sensitive to changes in temperature or moisture at the continental scale. In particular, identifying and mapping differences in interactions between soil carbon and redox-active elements (for example, iron and manganese) may help pinpoint areas of the landscape that could be hotspots of soil carbon-climate feedbacks.