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The effect of vascular plants on carbon turnover and methane emissions from a tundra wetland

Author:
  • Lena Ström
  • Anna Ekberg
  • Mikhail Mastepanov
  • Torben Christensen
Publishing year: 2003
Language: English
Pages: 1185-1192
Publication/Series: Global Change Biology
Volume: 9
Issue: 8
Document type: Journal article
Publisher: Wiley-Blackwell

Abstract english

This paper investigates how vascular plants affect carbon flow and the formation and emission of the greenhouse gas methane (CH4 ) in an arctic wet tundra ecosystem in NE Greenland. We present a field experiment where we studied, in particular, how species-specific root exudation patterns affect the availability of acetate, a hypothesized precursor of CH4 formation. We found significantly higher acetate formation rates in the root vicinity of Eriophorum scheuchzeri compared with another dominating sedge in the wetland, i.e. Dupontia psilosantha . Furthermore a shading treatment, which reduced net photosynthesis, resulted in significantly decreased formation rates of acetate. We also found that the potential CH4 production of the peat profile was highly positively correlated to the concentration of acetate at the respective depths, whereas it was negatively correlated to the concentration of total dissolved organic carbon. This suggests that acetate is a substrate of importance to the methanogens in the studied ecosystem and that acetate concentration in this case can serve as a predictor of substrate quality. To further investigate the importance of acetate as a predecessor to CH4 , we brought an intact peat-plant monolith system collected at the field site in NE Greenland to the laboratory, sealed it hermetically and studied the decomposition of (14) C-labelled acetate injected at the depth of methanogenic activity. After 4 h, (14) CH4 emission from the monolith could be observed. In conclusion, allocation of recently fixed carbon to the roots of certain species of vascular plants affects substrate quality and influence CH4 formation.

Keywords

  • Physical Geography
  • vascular plant effects
  • quality
  • substrate
  • methanogens
  • methane emission
  • acetate
  • arctic wetlands

Other

Published
  • ISSN: 1354-1013
E-mail: lena [dot] strom [at] nateko [dot] lu [dot] se

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Dept of Physical Geography and Ecosystem Science

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Department of Physical Geography and Ecosystem Science
Lund University
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