While most people think first of atmospheric carbon emissions from fossil fuels when considering climate change, the planet’s soil actually stores more carbon and could become a major source of carbon release or a mitigation tactic in the years ahead. Just how soils store carbon, when and how much they release to the atmosphere, and how to get them to absorb more is the subject of intense research as scientists race to understand the processes at play, predict environmental change and use that knowledge to help heal the planet.

At the Department of Energy’s Oak Ridge National Laboratory, biogeochemist Elizabeth Herndon is working with colleagues to investigate a piece of the puzzle that has received little attention thus far: the role of manganese in the carbon cycle. Manganese is a metal micronutrient involved in plant growth and function. For example, manganese is used in photosynthesis to convert water molecules to oxygen. Manganese also influences other ecosystem carbon dynamics such as the breakdown of plant matter and stabilization of organic matter in soils.

The ORNL scientists detailed how further research can better inform understanding of the metal’s effects on carbon and the climate in a recent paper. Herndon and the team posed questions that science can address, such as how fungi use manganese to break down tough plant components like lignin, and how the manganese present in plant tissue could be used to help degrade organic matter — processes important to binding carbon in soils.