BER launches Environmental System Science Program. Visit our new website under construction!

U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights


A Slippery Slope: Soil Carbon Destabilization
Published: July 29, 2019
Posted: October 21, 2019

Carbon gain or loss depends on the balance between competing biological, chemical, and physical reactions.

The Science
Despite a breadth of research on carbon accrual and persistence in soils, scientists lack a strong, general understanding of the mechanisms through which soil organic carbon (SOC) is destabilized in soils. In a new review article, researchers synthesized principles of soil chemistry, physics, and biology to explain carbon loss in soils. They found that destabilization does not equal stabilization in reverse. Rather, carbon gain or loss depends on the balance among competing biological, chemical, and physical reactions that can be altered by changes in weather and temperature.

The Impact
Rates of soil carbon respiration are increasing with current changes in climate and land use. Therefore, understanding destabilization processes in the soil carbon cycle is imperative. This review informs a more robust understanding of the processes that result in carbon loss and feedbacks to the Earth system. With this context, empirical and computational scientists can target better questions about the potential for soils to affect climate through the carbon cycle, which is important for improving predictive biogeochemical and climate models.

Summary
Most empirical and modeling research on soil carbon dynamics focuses on processes that control and promote carbon stabilization. However, the mechanisms through which SOC is destabilized in soils may be even more important to understand. Destabilization processes occur as SOC shifts from a “protected” or passive state, to an “available” or active state. In the available state, microbes can transform soil carbon to gaseous or soluble forms that are then lost from the soil.

The reviewers, from Pacific Northwest National Laboratory, Dartmouth College, and Oregon State University, considered two well-known phenomena—soil carbon priming and the Birch effect—to show how different mechanisms interact to increase carbon losses. They categorized carbon destabilization processes into three general categories: (1) release from physical occlusion through processes such as tillage, bioturbation, or freeze-thaw and wetting-drying cycles; (2) carbon desorption from soil solids and colloids; and (3) increased carbon metabolism by microbes.

By considering the different physical, chemical, and biological controls as processes that contribute to SOC destabilization, researchers can develop new hypotheses about the persistence and vulnerability of carbon in soils and make more accurate and robust predictions of soil carbon cycling in a changing environment.

Contacts (BER PM)
Daniel Stover
U.S. Department of Energy Office of Science, Office of Biological and Environmental Research
Climate and Environmental Sciences Division (SC-23.1)
Terrestrial Ecosystem Science
daniel.stover@science.doe.gov

PNNL Contact
Vanessa Bailey, Pacific Northwest National Laboratory, vanessa.bailey@pnnl.gov

Funding
V. L. Bailey was supported by the Terrestrial Ecosystem Science program of the Office of Biological and Environmental Research, within the U.S. Department of Energy (DOE) Office of Science. Pacific Northwest National Laboratory is operated for DOE by Battelle Memorial Institute under contract DE-AC05-557 76RL01830. K. Lajtha was supported by National Science Foundation DEB-1257032.

Publication
Bailey, V., C. Hicks Pries, and K. Lajtha. “What do we know about soil carbon?” Environmental Research Letters 14(8), 083004 (2019). [DOI: 10.1088/1748-9326/ab2c11].

Topic Areas:

  • Research Area: Terrestrial Ecosystem Science
  • Research Area: Carbon Cycle, Nutrient Cycling

Division: SC-33.1 Earth and Environmental Sciences Division, BER

 

BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

Mar 23, 2021
Molecular Connections from Plants to Fungi to Ants
Lipids transfer energy and serve as an inter-kingdom communication tool in leaf-cutter ants&rsqu [more...]

Mar 19, 2021
Microbes Use Ancient Metabolism to Cycle Phosphorus
Microbial cycling of phosphorus through reduction-oxidation reactions is older and more widespre [more...]

Feb 22, 2021
Warming Soil Means Stronger Microbe Networks
Soil warming leads to more complex, larger, and more connected networks of microbes in those soi [more...]

Jan 27, 2021
Labeling the Thale Cress Metabolites
New data pipeline identifies metabolites following heavy isotope labeling.

Analysis [more...]

Aug 31, 2020
Novel Bacterial Clade Reveals Origin of Form I Rubisco
Objectives

  • All plant biomass is sourced from the carbon-fixing enzyme Rub [more...]

List all highlights (possible long download time)