HR: 1340h
AN: B13C-0232    [Abstracts]
TI: Soil Carbon Accrual from C3 and C4 Plants Sources in a Restored Tallgrass Prairie Chronosequence
AU: * O'Brien, S L
EM: sobrie1@uic.edu
AF: Argonne National Lab, 9700 S Cass Ave, Argonne, IL 60439 United States
AU: * O'Brien, S L
EM: sobrie1@uic.edu
AF: University of Illinois at Chicago, 845 W Taylor St M/C 066, Chicago, IL 60607 United States
AU: Jastrow, J D
EM: jdjastrow@anl.gov
AF: Argonne National Lab, 9700 S Cass Ave, Argonne, IL 60439 United States
AU: Gonzalez Meler, M A
EM: mmeler@uic.edu
AF: University of Illinois at Chicago, 845 W Taylor St M/C 066, Chicago, IL 60607 United States
AB: Rapid anthropogenic increase in atmospheric CO2 may have serious consequences for global climate and ecosystem function and integrity. Cultivation of natural areas to agriculture is responsible for substantial losses of carbon (C) from soil to the atmosphere through the alteration of water regimes, decreased annual primary production, and tillage which disrupts the soil structure that helps protect organic matter from decomposition. Due to their high belowground productivity and often well structured soils, prairie restorations are good candidates for restoring soil C to levels that existed prior to cultivation and thus can serve as a net C sink. After restoration, organic matter inputs generally outpace C release by respiration, resulting in a net C gain in the ecosystem. The cool season C3 and warm season C4 plants that compose prairies discriminate differently against the natural 13C stable C isotope of atmospheric CO2. The isotopic signature of soil C pools can therefore provide mechanistic understanding of dynamics of soil organic matter linked to prairie species composition. Soils were sampled from a prairie restoration chronosequence and a C3 pasture at Fermi National Accelerator Laboratory in Batavia, IL. In the prairies, soil gained C over a 15-year sampling interval, while the pasture remained in equilibrium with respect to soil C. Stable C isotopes were measured in whole soil from the C3 pasture and C3/C4 mixed prairies of different ages over a sampling interval to assess if accrued C is primarily from C3 or C4 vegetative sources, which will provide insight into C3-C and C4-C cycling in restored prairies and the mechanisms of C accrual in soil.
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting