Purdue Climate Change Research Center

Soil Carbon Responses to Atmospheric CO2 Enrichment

Funded by Department of Energy

To date, most field-scale CO2 enrichment studies have been unable to detect significant changes in soil C against the relatively large, spatially heterogeneous pool of existing soil organic matter, leading some to conclude that the potential for increased soil C is limited. A further concern is that any CO2-stimulated increases in soil C will be allocated primarily to rapidly cycling, labile pools with little, if any, long-term stabilization. In this project, Filley and collaborators will study the accrual of soil C and its potential longevity at the sweetgum Free Air CO2 Enrichment (FACE) experiment at Oak Ridge National Laboratory (ORNL). The measurable linear increase in soil organic C that has been observed with repeated sampling at the ORNL FACE, coupled with the 13C label present in the elevated CO2 treatment provides a unique opportunity to investigate both soil C responses to atmospheric CO2 enrichment in this deciduous forest and fundamental questions regarding the cycling, turnover, and stabilization of specific soil C pools derived from distinct plant biopolymer components.

The team will evaluate the dynamics, sources, and stability of functionally meaningful soil C pools and their response to atmospheric CO2 enrichment, with the ultimate goal of providing information that can be used to help validate, parameterize, and improve terrestrial C cycle models and provide policymakers with the tools necessary to determine safe levels of greenhouse gases for the Earth system.

Investigator(s)

• Timothy Filley, EAS
• J. Jastrow, Argonne National Laboratory
• T. Boutton, Texas A&M
• M-G. Meler, Illinois, Chicago
• R. Matamala, Illinois, Chicago