A team of researchers led a study that has revealed valuable details about the role that calcite plays in the long-term stability of soil organic matter (SOM), which represents the Earth’s largest terrestrial carbon reservoir. Maintaining the stability of this reservoir is essential for ensuring that carbon dioxide emissions into the atmosphere do not increase.
This study details the chemical composition, coordination, and stability of calcium–organic associations that form when calcite mineral is exposed to organic matter. The results demonstrate that these associations are formed in the presence of dissolving calcite and organic matter components such as lignin and amino acids. The research team also found solution-derived (bi)carbonate in Ca–organic associations, indicating for the first time that an inorganic anion, such as (bi)carbonate, may be part of these associations. This research revealed that calcite dissolution and subsequent release of calcium promotes calcium–(bi)carbonate–organic associations with greater chemical stability and, possibly, higher environmental stability compared to non-calcium-bound organic matter.
Research was conducted at the Environmental Molecular Sciences Laboratory, a Department of Energy (DOE) user facility, and was sponsored by the Biological and Research program. The study also used resources at the Advanced Light Source, also a DOE Office of Science user facility.
