From Microbes to the Earth System – Upscaling Microbial Community Dynamics to Macro-scale Soil Carbon Models

Project Overview

Soil organic matter is the largest actively-cycling terrestrial reservoir of carbon, containing more than three times the carbon (C) present in vegetation globally. It is an integral component of natural and managed ecosystems, where it contains nutrients that support plant growth, retains water, improves water quality, and stores carbon to reduce greenhouse gas emissions. The amount of carbon sequestered in soils results from the long-term difference between plant carbon inputs and carbon dioxide (CO2) released by heterotrophic respiration. When the plant inputs that enter soil change due to anthropogenic land-use or climate-induced land-cover change, soil carbon storage also changes over decadal to centennial timescales as a result. However, the magnitude and location of such changes to soil organic carbon stocks are uncertain due to a paucity of data from long-term field experiments and a lack of multi-scale process representation in soil biogeochemical models. To this end, we used a combination of (1) collection, synthesis, and analysis of long-term experiments and field-scale soil carbon data, (2) theoretical investigation of emergent upscaled dynamics from micro-scale to macro-scale soil carbon models, and (3) diagnostics and cross-scale comparison of data and models, to quantify shortcomings of existing macro-scale models, propose scale-dependent formulations, and provide novel benchmarks for model-data comparisons. By integrating experimental data, process-based modeling, and nonlinear dynamical systems theory, the results of this project contribute to more accurate prediction of soil carbon cycling from refined soil models. Given the uncertainty and magnitude of the soil carbon sink, it is critically important to better constrain estimates of soil carbon cycling towards enhancing prediction of climate and land-use scenarios and informing mitigation actions.

Mission Impact

Soil is a critical global resource under threat with vast implications for food security and public health. Improved predictions of soil response to changes in plant inputs are of key interest to agriculture, land management, and climate change mitigation, and thus the results of this project address DOE's environmental security missions. This Lawrence Fellowship project supported LLNL's mission focus area in Energy and Climate Security and the Director's Carbon Initiative. Furthermore, this project complimented core competencies within: (i) Earth and Atmospheric Science by enabling improved prediction and resiliency to climate change; (ii) Nuclear, Chemical, and Isotopic Science and Technology via pore-scale modeling that links to measurements of microbial growth and turnover using quantitative stable isotope probing; and (iii) Bioscience and Bioengineering via understanding how the soil microbiome regulates soil carbon storage and health. The project also enhanced Lawrence Livermore National Laboratory's (LLNL) visibility in the terrestrial carbon cycle modeling community, through workforce development, new multi-institution collaborations, as well as potential sponsors of future work.

Publications, Presentations, and Patents

Rose Z. Abramoff, Bertrand Guenet, Haicheng Zhang, Katerina Georgiou, Xiaofeng Xu, Raphael A. Viscarra Rossel, Wenping Yuan, Philippe Ciais, "Improved global-scale predictions of soil carbon stocks with Millennial Version 2," Soil Biology and Biochemistry, Volume 164, 2022,108466, SSN 0038-0717, https://doi.org/10.1016/j.soilbio.2021.108466.

Georgiou, Katerina, Avni Malhotra, William W. Wieder, Jaqueline H. Ennis, Melannie D. Hartman, Benjamin N. Sulman, Asmeret Asefaw Berhe, et al. "Divergent Controls of Soil Organic Carbon Between Observations and Process-based Models." Biogeochemistry (2021). Biogeochemistry 156, 5–17 (2021). https://doi.org/10.1007/s10533-021-00819-2. [LLNL-JRNL-823855]

Georgiou, Katerina, Robert B. Jackson, Olga Vinduskova, Rose Z. Abramoff, Anders Ahlstrom, Wenting Feng, Jennifer W. Harden, Adam F. A. Pellegrini, H. Wayne Polley, Jennifer L. Soong, William J. Riley, Margaret S. Torn. "Global stocks and capacity of mineral-associated soil organic carbon." Nature Communications (2022). Nat Commun 13, 3797 (2022). https://doi.org/10.1038/s41467-022-31540-9. [LLNL-JRNL-825882]

Kristensen, Jeppe A., Jens-Christian Svenning, Katerina Georgiou, Yadvinder Malhi. "Can Large Herbivores Stabilize Ecosystem Carbon?" Trends in Ecology & Evolution (2021). Volume 37, Issue 2, February 2022, Pages 117-128.https://doi.org/10.1016/j.tree.2021.09.006. [LLNL-JRNL-825879]

Pellegrini, Adam F. A., Anthony C. Caprio, Katerina Georgiou, Colin Finnegan, Sarah E. Hobbie, Jeffery A. Hatten, Robert B. Jackson. "Low‐intensity Frequent Fires in Coniferous Forests Transform Soil Organic Matter in Ways That May Offset Ecosystem Carbon Losses." Glob Chang Biol. 2021 Aug;27(16):3810-3823. doi: 10.1111/gcb.15648. [LLNL-JRNL-821940]

Pellegrini, Adam F. A., Jennifer Harden, Katerina Georgiou, Kyle S. Hemes, Avni Malhotra, Connor J. Nolan, Robert B. Jackson. "Fire effects on the persistence of soil organic matter and the implications for long-term carbon storage." Nature Geoscience (2022). December 2021 Nature Geoscience 15(1) DOI:10.1038/s41561-021-00867-1. [LLNL-JRNL-825832]

Pellegrini, Adam F. A., Peter B. Reich, Sarah E. Hobbie, Corli Coetsee, Benjamin Wigley, Edmund February, Katerina Georgiou, Cesar Terrer, E.N.J. Brookshire, Anders Ahström, Lars Nieradzik, Stephen Sitch, Joe R. Melton, Matthew Forrest, Fang Li, Stijn Hantsen, Chantelle Burton, Chao Yue, Philippe Ciais, Robert B. Jackson. "Soil carbon storage capacity of drylands under altered fire regimes." Nat. Clim. Chang. 13, 1089–1094 (2023). https://doi.org/10.1038/s41558-023-01800-7 [LLNL-JRNL-850584]

Pierson, Derek, Kathleen A. Lohse, William R. Wieder, Nicholas R. Patton, Jeremy Facer, Marie-Anne de Graaff, Katerina Georgiou, Mark S. Seyfried, Gerald Flerchinger, and Ryan Will. 2022. "Optimizing Process-Based Models to Predict Current and Future Soil Organic Carbon Stocks at High-Resolution." Sci Rep. 2022 Jun 25;12(1):10824. doi: 10.1038/s41598-022-14224-8. [LLNL-JRNL- 835092]

Slessarev, Eric, Allegra Mayer, Courtland Kelly, Katerina Georgiou, Jennifer Pett-Ridge, Erin Nuccio. "Initial soil organic carbon stocks govern changes in soil carbon: reality or artifact?" Global Change Biology, 29 (5), 1239-1247 (2023). First published: 21 October 2022 https://doi.org/10.1111/gcb.16491 [LLNL-JRNL-839427]

Sokol, Noah, Emily D. Whalen, Andrea Jilling, Cynthia Kallenbach, Jennifer Pett-Ridge, Katerina Georgiou. "Global distribution, formation, and fate of mineral-associated soil organic matter under a changing climate: A trait-based perspective." Functional Ecology (2022). https://doi.org/10.1111/1365-2435.14040 [LLNL-JRNL-829275]

Villarino, Sebastian H., Emir Talab, Luciano Contisciani, Cecilia Videla, Paula Di Geronimo, Matias E. Mastrángelo, Katerina Georgiou, Robert B. Jackson, Gervasio Piñeiro. "A large nitrogen supply from the stable mineral-associated soil organic matter fraction." Biology and Fertility of Soils, 1-9 (2023). July 2023 59(7) DOI:10.1007/s00374-023-01755-z. [LLNL-JRNL-850989]

Wolf, Julika, Asch Johanna, Feng Tian, Katerina Georgiou, Anders Ahlström. "Canopy responses of Swedish primary and secondary forests to the 2018 drought.: Environmental Research Letters, 18 (6), 064044 (2023). DOI: 10.1088/1748-9326/acd6a8 [LLNL-JRNL-835562]

Katerina Georgiou, et al., "Biome- to Global-scale Controls on Soil Carbon Storage: Divergence Between Observations and Process-based Models" (Oral Presentation, AGU Fall Meeting, Virtual, 2020). [LLNL-PRES-817702]

Katerina Georgiou, "Machine Learning Emulators Reveal Divergence in Soil Carbon Controls Between Observations and Process-based Models" (Invited Oral Presentation, CLAND Workshop on Machine Learning for Climate, Virtual, 2020). [LLNL-PRES-817702]

Katerina Georgiou, et al.,"Looking under the hood: benchmarking soil organic matter pool distributions at the global-scale" (Oral Presentation, AGU Fall Meeting, New Orleans, LA, Dec 2021). [LLNL-PRES-830060]

Katerina Georgiou, "Biogeochemical models for projections of climate impacts" (Invited Oral Presentation, LLNL Climate Impacts Webinar Series, Livermore, CA, 2022).  [LLNL-PRES-830533]

Katerina Georgiou,"Soil carbon saturation: mineralogical capacity and biotic controls" (Invited Oral Presentation, ISCN-AGU Webinar Series, Livermore, CA, 2022). [LLNL-PRES-832913]

Katerina Georgiou, "Global capacity and controls of mineral-associated soil organic carbon in observations and models" (Invited Seminar Presentation, University of Vienna, Vienna, Austria, 2022). [LLNL-PRES-832913]

Katerina Georgiou et al., "Global distribution and climatological temperature sensitivity of soil organic matter fractions in observations and models" (Invited Oral Presentation, EGU General Assembly, 2022). [LLNL-PRES-830060]

Katerina Georgiou, et al.,"Modeling population-level controls on soil microbial turnover" (Poster Presentation, AGU Fall Meeting, Vienna, Austria, 2022). [LLNL-POST-844952]

Katerina Georgiou, et al., "Modeling population-level controls on soil microbial turnover across scales" (Oral Presentation, EGU General Assembly,Vienna, Austria, April 2023). [LLNL-PRES-849217]

Katerina Georgiou, et al., "Improving representations of soil microbial processes in ecosystem models" (Invited Oral Presentation, ASM Meeting, Houston, TX, June 2023). [LLNL-PRES-850579]