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

BER Research Highlights


Uncovering the Secrets of Carbon in Soil Organic Matter
Published: November 17, 2011
Posted: February 24, 2012

Soil organic matter (SOM) is a heterogeneous mixture of partially decomposed, plant- and microbial-derived materials that plays an important role in the global carbon cycle. The carbon associated with some components of SOM can persist belowground for centuries to millennia, making these pools crucial carbon reservoirs. However, these long-lived carbon pools and the factors controlling their persistence in soil are not well characterized, because they are extremely challenging to isolate. A team led by Argonne National Laboratory used a novel approach combining sequential physical and chemical fractionations with two naturally occurring carbon isotopic tracers to divide the SOM into pools with average turnover times that ranged from 1 to over 3,000 years. They discovered that the SOM pools associated with soil minerals, which typically have been characterized as having extremely long lifetimes, are actually composed of a mixture of rapidly cycling pools and pools with much longer residence times. Further, the study found that the rapidly cycling pools accounted for a much greater proportion of the total soil carbon than is generally represented in SOM models. These results provide new insight into soil carbon dynamics, since SOM pools with long turnover times were previously thought to be relatively homogenous and practically inert. The findings can inform models used to predict the contributions of soils to the carbon cycle and the responses of SOM to climatic change.

Reference: O'Brien, S. L., J. D. Jastrow, L. J. McFarlane, T. P. Guilderson, and M. A. Gonzalez-Meler. 2012. "Decadal Cycling within Long-Lived Carbon Pools Revealed by Dual Isotopic Analysis of Mineral-Associated Soil Organic Matter," Biogeochemistry, DOI: 10.1007/s10533-011-9673-0. (Reference link)

Contact: Mike Kuperberg, SC-23.1, (301) 903-3281, Daniel Stover, SC-23.1, (301) 903-0289
Topic Areas:

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

Division: SC-23.1 Climate 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

Aug 24, 2019
New Approach for Studying How Microbes Influence Their Environment
A diverse group of scientists suggests a common framework and targeting of known microbial processes [more...]

Aug 08, 2019
Nutrient-Hungry Peatland Microbes Reduce Carbon Loss Under Warmer Conditions
Enzyme production in peatlands reduces carbon lost to respiration under future high temperatures. [more...]

Aug 05, 2019
Amazon Forest Response to CO2 Fertilization Dependent on Plant Phosphorus Acquisition
AmazonFACE Model Intercomparison. The Science Plant growth is dependent on the availabi [more...]

Jul 29, 2019
A Slippery Slope: Soil Carbon Destabilization
Carbon gain or loss depends on the balance between competing biological, chemical, and physical reac [more...]

Jul 15, 2019
Field Evaluation of Gas Analyzers for Measuring Ecosystem Fluxes
How gas analyzer type and correction method impact measured fluxes. The Science A side- [more...]

List all highlights (possible long download time)