Julie Jastrow, PI (jdjastrow@anl.gov)

Determination of the potential carbon sink strength of terrestrial ecosystems requires a better understanding and improved quantization of the processes involved in soil carbon storage and turnover. Soil carbon can be stabilized because of its biochemical recalcitrance, but soil structure plays a dominant role in controlling microbial turnover processes. Relatively labile material can become physically protected from decomposition by incorporation into soil aggregates. Thus, an understanding of the processes involved in the formation, stabilization, and degradation of aggregates provides a theoretical basis for isolating measurable carbon pools with functionally meaningful relationships to soil carbon dynamics. As part of the DOE-BER Terrestrial Carbon Processes Program (TCP), we are using physical and biological fractionation techniques (1) to identify and quantify measurable carbon pools, which may improve parameterization of the conceptually defined pools used by models to simulate soil organic matter (SOM) dynamics, and (2) to determine whether the size, quality, and dynamics of these measurable carbon pools are modified under elevated atmospheric concentrations of CO2. This study not only investigates the potential effects of elevated atmospheric CO2 on soil carbon dynamics, but it will help to validate and improve the estimates of carbon pools and fluxes used in SOM simulation models, allowing extrapolation of results to the broader scales necessary to predict the role of terrestrial ecosystems in the global carbon cycle.

Publications List (PDF)

Links:

FACE (Free Air CO2 Enrichment) web site: http://cdiac.esd.ornl.gov/programs/FACE/face.html
Sweetgum FACE web site: http://www.esd.ornl.gov/facilities/ORNL-FACE/
Aspen FACE (FACTS II) web site:  http://aspenface.mtu.edu/
SoyFACE web site:  http://www.soyface.uiuc.edu/index.htm