Warming-related increases in soil CO2 efflux are explained by increased below-ground carbon flux

Christian P. Giardina, Creighton M. Litton, Susan E. Crow, Gregory P. Asner

Research output: Contribution to journalArticle

79 Citations (Scopus)

Abstract

The universally observed exponential increase in soil-surface CO 2 efflux ('soil respiration'; F S) with increasing temperature has led to speculation that global warming will accelerate soil-organic-carbon (SOC) decomposition, reduce SOC storage, and drive a positive feedback to future warming. However, interpreting temperature-F S relationships, and so modelling terrestrial carbon balance in a warmer world, is complicated by the many sources of respired carbon that contribute to F S (ref.) and a poor understanding of how temperature influences SOC decomposition rates. Here we quantified F S, litterfall, bulk SOC and SOC fraction size and turnover, and total below-ground carbon flux (TBCF) across a highly constrained 5.2 °C mean annual temperature (MAT) gradient in tropical montane wet forest. From these, we determined that: increases in TBCF and litterfall explain >90% of the increase in F S with MAT; bulk SOC and SOC fraction size and turnover rate do not vary with MAT; and increases in TBCF and litterfall do not influence SOC storage or turnover on century to millennial timescales. This gradient study shows that for tropical montane wet forest, long-term and whole-ecosystem warming accelerates below-ground carbon processes with no apparent impact on SOC storage.

Original languageEnglish (US)
Pages (from-to)822-827
Number of pages6
JournalNature Climate Change
Volume4
Issue number9
DOIs
StatePublished - Sep 11 2014
Externally publishedYes

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carbon flux
turnover
warming
organic carbon
soil
litterfall
speculation
carbon sequestration
organic soil
temperature
decomposition
carbon balance
carbon
soil respiration
temperature gradient
global warming
soil surface
timescale
ecosystem

ASJC Scopus subject areas

  • Environmental Science (miscellaneous)
  • Social Sciences (miscellaneous)

Cite this

Warming-related increases in soil CO2 efflux are explained by increased below-ground carbon flux. / Giardina, Christian P.; Litton, Creighton M.; Crow, Susan E.; Asner, Gregory P.

In: Nature Climate Change, Vol. 4, No. 9, 11.09.2014, p. 822-827.

Research output: Contribution to journalArticle

Giardina, Christian P. ; Litton, Creighton M. ; Crow, Susan E. ; Asner, Gregory P. / Warming-related increases in soil CO2 efflux are explained by increased below-ground carbon flux. In: Nature Climate Change. 2014 ; Vol. 4, No. 9. pp. 822-827.
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