Abstract
Quantifying the upper limit of stable soil carbon storage is essential for guiding policies to increase soil carbon storage. One pool of carbon considered particularly stable across climate zones and soil types is formed when dissolved organic carbon sorbs to minerals. We quantified, for the first time, the potential of mineral soils to sorb additional dissolved organic carbon (DOC) for six soil orders. We compiled 402 laboratory sorption experiments to estimate the additional DOC sorption potential, that is the potential of excess DOC sorption in addition to the existing background level already sorbed in each soil sample. We estimated this potential using gridded climate and soil geochemical variables within a machine learning model. We find that mid- and low-latitude soils and subsoils have a greater capacity to store DOC by sorption compared to high-latitude soils and topsoils. The global additional DOC sorption potential for six soil orders is estimated to be 107 ± 13 Pg C to 1 m depth. If this potential was realized, it would represent a 7% increase in the existing total carbon stock.
| Original language | English |
|---|---|
| Pages (from-to) | 127-142 |
| Number of pages | 16 |
| Journal | Biogeochemistry |
| Volume | 152 |
| Issue number | 2-3 |
| DOIs | |
| State | Published - Feb 2021 |
Funding
RZA was supported by the French government grant “Make Our Planet Great Again” and by a Marie Skłodowska–Curie Individual Fellowship (Grant No. 834-169) from the European Union’s Horizon 2020 program. KG was supported by a US Department of Agriculture NIFA Postdoctoral Fellowship. BG was supported by French government under the ANR “Investissements d’avenir” program with the reference CLAND ANR-16-CONV-0003. MAM's participation in this research was supported through an Early Career Award from the United States Department of Energy, Office of Science, Office of Biological and Environmental Research. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the United States Department of Energy under contract DE-AC05-00OR22725. This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). RZA was supported by the French government grant “Make Our Planet Great Again” and by a Marie Skłodowska–Curie Individual Fellowship (Grant No. 834-169) from the European Union’s Horizon 2020 program. KG was supported by a US Department of Agriculture NIFA Postdoctoral Fellowship. BG was supported by French government under the ANR “Investissements d’avenir” program with the reference CLAND ANR-16-CONV-0003. MAM's participation in this research was supported through an Early Career Award from the United States Department of Energy, Office of Science, Office of Biological and Environmental Research. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the United States Department of Energy under contract DE-AC05-00OR22725.
Keywords
- Additional sorption potential
- Mineral association
- Saturation
- Soil organic carbon
- Sorption