Response of CO2 exchange in a tussock tundra ecosystem to permafrost thaw and thermokarst development

Jason Vogel, Edward A.G. Schuur, Christian Trucco, Hanna Lee

Research output: Contribution to journalArticlepeer-review

88 Scopus citations


Climate change in high latitudes can lead to permafrost thaw, which in ice-rich soils can result in ground subsidence, or thermokarst. In interior Alaska, we examined seasonal and annual ecosystem CO 2 exchange using static and automatic chamber measurements in three areas of a moist acidic tundra ecosystem undergoing varying degrees of permafrost thaw and thermokarst development. One site had extensive thermokarst features, and historic aerial photography indicated it was present at least 50 years prior to this study. A second site had a moderate number of thermokarst features that were known to have developed concurrently with permafrost warming that occurred 15 years prior to this study. A third site had a minimal amount of thermokarst development. The areal extent of thermokarst features reflected the seasonal thaw depth. The "extensive" site had the deepest seasonal thaw depth, and the "moderate" site had thaw depths slightly, but not significantly deeper than the site with "minimal" thermokarst development. Greater permafrost thaw corresponded to significantly greater gross primary productivity (GPP) at the moderate and extensive thaw sites as compared to the minimal thaw site. However, greater ecosystem respiration (Reco) during the spring, fall, and winter resulted in the extensive thaw site being a significant net source of CO2 to the atmosphere over 3 years, while the moderate thaw site was a CO2 sink. The minimal thaw site was near CO 2 neutral and not significantly different from the extensive thaw site. Thus after permafrost thaw, initial periods of increased GPP and net CO2 uptake could be offset by elevated Reco during the winter, spring, and fall.

Original languageEnglish (US)
Article numberG04018
JournalJournal of Geophysical Research: Biogeosciences
Issue number4
StatePublished - Oct 2009
Externally publishedYes

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology


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