Tundra Underlain By Thawing Permafrost Persistently Emits Carbon to the Atmosphere Over 15 Years of Measurements

Edward A.G. Schuur, Rosvel Bracho, Gerardo Celis, E. Fay Belshe, Chris Ebert, Justin Ledman, Marguerite Mauritz, Elaine F. Pegoraro, César Plaza, Heidi Rodenhizer, Vladimir Romanovsky, Christina Schädel, David Schirokauer, Meghan Taylor, Jason G. Vogel, Elizabeth E. Webb

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Warming of the Arctic can stimulate microbial decomposition and release of permafrost soil carbon (C) as greenhouse gases, and thus has the potential to influence climate change. At the same time, plant growth can be stimulated and offset C release. This study presents a 15-year time series comprising chamber and eddy covariance measurements of net ecosystem C exchange in a tundra ecosystem in Alaska where permafrost has been degrading due to regional warming. The site was a carbon dioxide source to the atmosphere with a cumulative total loss of 781.6 g C m−2 over the study period. Both gross primary productivity (GPP) and ecosystem respiration (Reco) were already likely higher than historical levels such that increases in Reco losses overwhelmed GPP gains in most years. This shift to a net C source to the atmosphere likely started in the early 1990s when permafrost was observed to warm and thaw at the site. Shifts in the plant community occur more slowly and are likely to constrain future GPP increases as compared to more rapid shifts in the microbial community that contribute to increased Reco. Observed rates suggest that cumulative net soil C loss of 4.18–10.00 kg C m−2—8%–20% of the current active layer soil C pool—could occur from 2020 to the end of the century. This amount of permafrost C loss to the atmosphere represents a significant accelerating feedback to climate change if it were to occur at a similar magnitude across the permafrost region.

Original languageEnglish (US)
Article numbere2020JG006044
JournalJournal of Geophysical Research: Biogeosciences
Volume126
Issue number6
DOIs
StatePublished - Jun 2021

Keywords

  • Arctic
  • carbon
  • eddy covariance
  • permafrost
  • tundra

ASJC Scopus subject areas

  • Soil Science
  • Forestry
  • Water Science and Technology
  • Palaeontology
  • Atmospheric Science
  • Aquatic Science
  • Ecology

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