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Snowpack fluxes of methane and carbon dioxide from high Arctic tundra

Pirk, Norbert LU ; Tamstorf, Mikkel P.; Lund, Magnus LU ; Mastepanov, Mikhail LU ; Pedersen, Stine H.; Mylius, Maria R.; Parmentier, Frans Jan W LU ; Christiansen, Hanne H. and Christensen, Torben R. LU (2016) In Journal of Geophysical Research - Biogeosciences 121(11). p.2886-2900
Abstract

Measurements of the land-atmosphere exchange of the greenhouse gases methane (CH4) and carbon dioxide (CO2) in high Arctic tundra ecosystems are particularly difficult in the cold season, resulting in large uncertainty on flux magnitudes and their controlling factors during this long, frozen period. We conducted snowpack measurements of these gases at permafrost-underlain wetland sites in Zackenberg Valley (NE Greenland, 74°N) and Adventdalen Valley (Svalbard, 78°N), both of which also feature automatic closed chamber flux measurements during the snow-free period. At Zackenberg, cold season emissions were 1 to 2 orders of magnitude lower than growing season fluxes. Perennially, CH4 fluxes resembled the... (More)

Measurements of the land-atmosphere exchange of the greenhouse gases methane (CH4) and carbon dioxide (CO2) in high Arctic tundra ecosystems are particularly difficult in the cold season, resulting in large uncertainty on flux magnitudes and their controlling factors during this long, frozen period. We conducted snowpack measurements of these gases at permafrost-underlain wetland sites in Zackenberg Valley (NE Greenland, 74°N) and Adventdalen Valley (Svalbard, 78°N), both of which also feature automatic closed chamber flux measurements during the snow-free period. At Zackenberg, cold season emissions were 1 to 2 orders of magnitude lower than growing season fluxes. Perennially, CH4 fluxes resembled the same spatial pattern, which was largely attributed to differences in soil wetness controlling substrate accumulation and microbial activity. We found no significant gas sinks or sources inside the snowpack but detected a pulse in the δ13C-CH4 stable isotopic signature of the soil's CH4 source during snowmelt, which suggests the release of a CH4 reservoir that was strongly affected by methanotrophic microorganisms. In the polygonal tundra of Adventdalen, the snowpack featured several ice layers, which suppressed the expected gas emissions to the atmosphere, and conversely lead to snowpack gas accumulations of up to 86 ppm CH4 and 3800 ppm CO2 by late winter. CH4 to CO2 ratios indicated distinctly different source characteristics in the rampart of ice-wedge polygons compared to elsewhere on the measured transect, possibly due to geomorphological soil cracks. Collectively, these findings suggest important ties between growing season and cold season greenhouse gas emissions from high Arctic tundra.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Arctic, carbon dioxide, methane, snowpack, tundra, wintertime
in
Journal of Geophysical Research - Biogeosciences
volume
121
issue
11
pages
15 pages
publisher
American Geophysical Union
external identifiers
  • scopus:85006324037
  • wos:000390686500008
ISSN
2169-8953
DOI
10.1002/2016JG003486
language
English
LU publication?
yes
id
5dbfca41-4035-476e-92a1-ef663b573d2f
date added to LUP
2017-01-12 07:48:58
date last changed
2017-09-18 11:36:06
@article{5dbfca41-4035-476e-92a1-ef663b573d2f,
  abstract     = {<p>Measurements of the land-atmosphere exchange of the greenhouse gases methane (CH<sub>4</sub>) and carbon dioxide (CO<sub>2</sub>) in high Arctic tundra ecosystems are particularly difficult in the cold season, resulting in large uncertainty on flux magnitudes and their controlling factors during this long, frozen period. We conducted snowpack measurements of these gases at permafrost-underlain wetland sites in Zackenberg Valley (NE Greenland, 74°N) and Adventdalen Valley (Svalbard, 78°N), both of which also feature automatic closed chamber flux measurements during the snow-free period. At Zackenberg, cold season emissions were 1 to 2 orders of magnitude lower than growing season fluxes. Perennially, CH<sub>4</sub> fluxes resembled the same spatial pattern, which was largely attributed to differences in soil wetness controlling substrate accumulation and microbial activity. We found no significant gas sinks or sources inside the snowpack but detected a pulse in the δ<sup>13</sup>C-CH<sub>4</sub> stable isotopic signature of the soil's CH<sub>4</sub> source during snowmelt, which suggests the release of a CH<sub>4</sub> reservoir that was strongly affected by methanotrophic microorganisms. In the polygonal tundra of Adventdalen, the snowpack featured several ice layers, which suppressed the expected gas emissions to the atmosphere, and conversely lead to snowpack gas accumulations of up to 86 ppm CH<sub>4</sub> and 3800 ppm CO<sub>2</sub> by late winter. CH<sub>4</sub> to CO<sub>2</sub> ratios indicated distinctly different source characteristics in the rampart of ice-wedge polygons compared to elsewhere on the measured transect, possibly due to geomorphological soil cracks. Collectively, these findings suggest important ties between growing season and cold season greenhouse gas emissions from high Arctic tundra.</p>},
  author       = {Pirk, Norbert and Tamstorf, Mikkel P. and Lund, Magnus and Mastepanov, Mikhail and Pedersen, Stine H. and Mylius, Maria R. and Parmentier, Frans Jan W and Christiansen, Hanne H. and Christensen, Torben R.},
  issn         = {2169-8953},
  keyword      = {Arctic,carbon dioxide,methane,snowpack,tundra,wintertime},
  language     = {eng},
  month        = {11},
  number       = {11},
  pages        = {2886--2900},
  publisher    = {American Geophysical Union},
  series       = {Journal of Geophysical Research - Biogeosciences},
  title        = {Snowpack fluxes of methane and carbon dioxide from high Arctic tundra},
  url          = {http://dx.doi.org/10.1002/2016JG003486},
  volume       = {121},
  year         = {2016},
}