Long-term effects of free air CO2 enrichment (FACE) on soil respiration

E. S. Bernhardt, J. J. Barber, J. S. Pippen, L. Taneva, J. A. Andrews, W. H. Schlesinger

Research output: Contribution to journalArticlepeer-review

90 Scopus citations

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 languageEnglish (US)
Pages (from-to)91-116
Number of pages26
JournalBiogeochemistry
Volume77
Issue number1
DOIs
StatePublished - Jan 1 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

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