Large greenhouse gas emissions from a temperate peatland pasture

Yit Arn Teh*, Whendee L. Silver, Oliver Sonnentag, Matteo Detto, Maggi Kelly, Dennis D. Baldocchi

*Corresponding author for this work

Research output: Contribution to journalArticle

68 Citations (Scopus)

Abstract

Agricultural drainage is thought to alter greenhouse gas emissions from temperate peatlands, with CH4 emissions reduced in favor of greater CO2 losses. Attention has largely focussed on C trace gases, and less is known about the impacts of agricultural conversion on N2O or global warming potential. We report greenhouse gas fluxes (CH4, CO2, N2O) from a drained peatland in the Sacramento-San Joaquin River Delta, California, USA currently managed as a rangeland (that is, pasture). This ecosystem was a net source of CH4 (25.8 +/- A 1.4 mg CH4-C m(-2) d(-1)) and N2O (6.4 +/- A 0.4 mg N2O-N m(-2) d(-1)). Methane fluxes were comparable to those of other managed temperate peatlands, whereas N2O fluxes were very high; equivalent to fluxes from heavily fertilized agroecosystems and tropical forests. Ecosystem scale CH4 fluxes were driven by "hotspots" (drainage ditches) that accounted for less than 5% of the land area but more than 84% of emissions. Methane fluxes were unresponsive to seasonal fluctuations in climate and showed minimal temporal variability. Nitrous oxide fluxes were more homogeneously distributed throughout the landscape and responded to fluctuations in environmental variables, especially soil moisture. Elevated CH4 and N2O fluxes contributed to a high overall ecosystem global warming potential (531 g CO2-C equivalents m(-2) y(-1)), with non-CO2 trace gas fluxes offsetting the atmospheric "cooling" effects of photoassimilation. These data suggest that managed Delta peatlands are potentially large regional sources of greenhouse gases, with spatial heterogeneity in soil moisture modulating the relative importance of each gas for ecosystem global warming potential.

Original languageEnglish
Pages (from-to)311-325
Number of pages15
JournalEcosystems
Volume14
Issue number2
Early online date1 Feb 2011
DOIs
Publication statusPublished - Mar 2011

Keywords

  • global warming potential
  • agricultural conversion
  • methane
  • Sacramento-San Joaquin Delta
  • nitrous oxide
  • tropical peatlands
  • carbon dioxide
  • carbon-dioxide
  • nitrous-oxide fluxes
  • drained temperate peatland
  • San-Joaquin delta
  • organic soils
  • methane emissions
  • global change
  • dairy-cows
  • land-use change
  • management
  • N2O emissions

Cite this

Teh, Y. A., Silver, W. L., Sonnentag, O., Detto, M., Kelly, M., & Baldocchi, D. D. (2011). Large greenhouse gas emissions from a temperate peatland pasture. Ecosystems, 14(2), 311-325. https://doi.org/10.1007/s10021-011-9411-4