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Trace gas exchange in a high-arctic valley 1. Variations in CO2 and CH4 flux between tundra vegetation types

Christensen, Torben LU ; Friborg, T; Sommerkorn, M; Kaplan, J; Illeris, L; Sögaard, H; Nordström, C and Jonasson, S (2000) In Global Biogeochemical Cycles 14(3). p.701-714
Abstract
Ecosystem exchanges of CO2 and CH4 were studied by chamber techniques in five different vegetation types in a high arctic valley at Zackenberg, NE Greenland. The vegetation types were categorized as Cassiope heath, hummocky fen, continuous fen, grass land and Salix arctica snowbed. Integrated daytime fluxes for the different vegetation types of the valley showed that the fen areas and the grassland, were significant sources of CH4 with a mean efflux of 6.3 mg CH4 m(-2) h(-1) and sinks for CO2, with almost -170 mg CO2 m(-2) hr(-1). The heath and snowbed areas had much lower carbon sequestration rates of about -25 mg CO2 m(-2) hr(-1) and were also sinks for CH4. Methane emissions from the valley dominated in the hummocky fens. Computation of... (More)
Ecosystem exchanges of CO2 and CH4 were studied by chamber techniques in five different vegetation types in a high arctic valley at Zackenberg, NE Greenland. The vegetation types were categorized as Cassiope heath, hummocky fen, continuous fen, grass land and Salix arctica snowbed. Integrated daytime fluxes for the different vegetation types of the valley showed that the fen areas and the grassland, were significant sources of CH4 with a mean efflux of 6.3 mg CH4 m(-2) h(-1) and sinks for CO2, with almost -170 mg CO2 m(-2) hr(-1). The heath and snowbed areas had much lower carbon sequestration rates of about -25 mg CO2 m(-2) hr(-1) and were also sinks for CH4. Methane emissions from the valley dominated in the hummocky fens. Computation of area integrated mean daytime flux values across all vegetation types of the entire valley bottom revealed that it was a sink of CO2 in the order of -96+/-33 mg CO2 m-2 hr-1 and a source of 1.9+/-0.7 m(-2) CH4 m(-2) hr(-1). These values were in accordance with eddy correlation measurements reported elsewhere in this issue and reflect a high-carbon exchange despite the high arctic location. In the fens, where the water table was at or above the soil surface, methane emissions increased with net ecosystem CO2 flux. In places with the water table below the soil surface, such as particularly in the hummocky parts of the fen, oxidation tended to become the dominant controlling factor on methane efflux. (Less)
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Global Biogeochemical Cycles
volume
14
issue
3
pages
701 - 714
publisher
American Geophysical Union
ISSN
0886-6236
language
English
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yes
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7bad4112-3835-4f87-87f4-ddd782651007 (old id 150753)
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http://www.agu.org/pubs/crossref/2000/1999GB001134.shtml
date added to LUP
2007-07-02 09:02:49
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2016-04-16 04:04:20
@article{7bad4112-3835-4f87-87f4-ddd782651007,
  abstract     = {Ecosystem exchanges of CO2 and CH4 were studied by chamber techniques in five different vegetation types in a high arctic valley at Zackenberg, NE Greenland. The vegetation types were categorized as Cassiope heath, hummocky fen, continuous fen, grass land and Salix arctica snowbed. Integrated daytime fluxes for the different vegetation types of the valley showed that the fen areas and the grassland, were significant sources of CH4 with a mean efflux of 6.3 mg CH4 m(-2) h(-1) and sinks for CO2, with almost -170 mg CO2 m(-2) hr(-1). The heath and snowbed areas had much lower carbon sequestration rates of about -25 mg CO2 m(-2) hr(-1) and were also sinks for CH4. Methane emissions from the valley dominated in the hummocky fens. Computation of area integrated mean daytime flux values across all vegetation types of the entire valley bottom revealed that it was a sink of CO2 in the order of -96+/-33 mg CO2 m-2 hr-1 and a source of 1.9+/-0.7 m(-2) CH4 m(-2) hr(-1). These values were in accordance with eddy correlation measurements reported elsewhere in this issue and reflect a high-carbon exchange despite the high arctic location. In the fens, where the water table was at or above the soil surface, methane emissions increased with net ecosystem CO2 flux. In places with the water table below the soil surface, such as particularly in the hummocky parts of the fen, oxidation tended to become the dominant controlling factor on methane efflux.},
  author       = {Christensen, Torben and Friborg, T and Sommerkorn, M and Kaplan, J and Illeris, L and Sögaard, H and Nordström, C and Jonasson, S},
  issn         = {0886-6236},
  language     = {eng},
  number       = {3},
  pages        = {701--714},
  publisher    = {American Geophysical Union},
  series       = {Global Biogeochemical Cycles},
  title        = {Trace gas exchange in a high-arctic valley 1. Variations in CO2 and CH4 flux between tundra vegetation types},
  volume       = {14},
  year         = {2000},
}