HR: 1340h
AN: B13C-0241 [Abstracts]
TI: Average Age of Soil Carbon Pools Contributing to Soil CO2 in a Forest Exposed to FACE
AU: * Taneva, L
EM: ttanev1@uic.edu
AF: University of Illinois at Chicago, 845 W. Taylor Street
M/C 066, Chicago, IL 60607
AU: Gonzalez-Meler, M
EM: mmeler@uic.edu
AF: University of Illinois at Chicago, 845 W. Taylor Street
M/C 066, Chicago, IL 60607
AU: Pippen, J S
EM: jspippen@duke.edu
AF: Duke University, Nicholas School of the Environment
Levine Science Research Center, Durham, NC 27708
AU: Schlesinger, W H
EM: schlesin@duke.edu
AF: Duke University, Nicholas School of the Environment
Levine Science Research Center, Durham, NC 27708
AB:
Soils represent the largest C reservoir in terrestrial ecosystems and have been highlighted as potential sinks for the
anthropogenic additions of CO$_{2}$ to the atmosphere. Soil organic matter (SOM) consists of several pools with different C
turnover rates. Long-term terrestrial C storage with rising atmospheric [CO$_{2}$] requires that a substantial proportion of
the additional C assimilated by plants is transferred to recalcitrant soil C pools and not quickly returned to the
atmosphere through R$_{S}$. Soil CO$_{2}$ reflects oxidation of SOM occurring in soil C pools of different turnover rates
and the age of soil CO$_{2}$ reflects the age of the C pools where the CO$_{2}$ originated. Soil CO$_{2}$ can therefore be
used to infer the age of the C pools contributing to the return of soil C to the atmosphere through R$_{S}$. At the FACTS-1
research site, an intact forest ecosystem has been exposed to elevated CO$_{2}$ for 8 years. The $^{13}$C composition of the
fumigation CO$_{2}$ functions as a continuous ecosystem label and the rate of incorporation of this label into SOM can be
used to identify the soil C pools contributing to soil CO$_{2}$. We used the long-term record of the \delta$^{13}C of soil
CO$_{2}$ to determine the age and relative contribution of the C pools contributing to soil CO$_{2}$ at different depths in
this forest ecosystem.
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting