Permafrost degradation stimulates carbon loss from experimentally warmed tundra

Susan M. Natali, Edward A.G. Schuur, Elizabeth E. Webb, Caitlin E.Hicks Pries, Kathryn G. Crummer

Research output: Contribution to journalArticlepeer-review

104 Scopus citations

Abstract

A large pool of organic carbon (C) has been accumulating in the Arctic for thousands of years because cold and waterlogged conditions have protected soil organic material from microbial decomposition. As the climate warms this vast and frozen C pool is at risk of being thawed, decomposed, and released to the atmosphere as greenhouse gasses. At the same time, some C losses may be offset by warming-mediated increases in plant productivity. Plant and microbial responses to warming ultimately determine net C exchange from ecosystems, but the timing and magnitude of these responses remain uncertain. Here we show that experimental warming and permafrost (ground that remains below 08C for two or more consecutive years) degradation led to a two-fold increase in net ecosystem C uptake during the growing season. However, warming also enhanced winter respiration, which entirely offset growing-season C gains. Winter C losses may be even higher in response to actual climate warming than to our experimental manipulations, and, in that scenario, could be expected to more than double overall net C losses from tundra to the atmosphere. Our results highlight the importance of winter processes in determining whether tundra acts as a C source or sink, and demonstrate the potential magnitude of C release from the permafrost zone that might be expected in a warmer climate.

Original languageEnglish (US)
Pages (from-to)602-608
Number of pages7
JournalEcology
Volume95
Issue number3
DOIs
StatePublished - 2014
Externally publishedYes

Keywords

  • Alaska
  • Arctic tundra
  • Carbon
  • Climate change
  • Eight Mile Lake
  • Net ecosystem exchange
  • Permafrost
  • USA

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

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