Abstract
Emissions of CO2 from soils make up one of the largest fluxes in the global C cycle, thus small changes in soil respiration may have large impacts on global C cycling. Anthropogenic additions of CO2 to the atmosphere are expected to alter soil carbon cycling, an important component of the global carbon budget. As part of the Duke Forest Free-Air CO2 Enrichment (FACE) experiment, we examined how forest growth at elevated (+200 ppmv) atmospheric CO2 concentration affects soil CO2 dynamics over 7 years of continuous enrichment. Soil respiration, soil CO 2 concentrations, and the isotopic signature of soil CO2 were measured monthly throughout the 7 years of treatment. Estimated annual rates of soil CO2 efflux have been significantly higher in the elevated plots in every year of the study, but over the last 5 years the magnitude of the CO2 enrichment effect on soil CO2 efflux has declined. Gas well samples indicate that over 7 years fumigation has led to sustained increases in soil CO2 concentrations and depletion in the δ 13C of soil CO2 at all but the shallowest soil depths.
Original language | English (US) |
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Pages (from-to) | 91-116 |
Number of pages | 26 |
Journal | Biogeochemistry |
Volume | 77 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2006 |
Keywords
- Carbon dioxide enrichment
- Del C
- Duke Forest
- FACE
- Soil CO
- Soil respiration
ASJC Scopus subject areas
- Environmental Chemistry
- Water Science and Technology
- Earth-Surface Processes