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| Titel |
The net exchange of methane with high Arctic landscapes during the summer growing season |
| VerfasserIn |
C. A. Emmerton, V. L. St. Louis, I. Lehnherr, E. R. Humphreys, E. Rydz, H. R. Kosolofski |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 12 ; Nr. 11, no. 12 (2014-06-16), S.3095-3106 |
| Datensatznummer |
250117462
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| Publikation (Nr.) |
 copernicus.org/bg-11-3095-2014.pdf |
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| Zusammenfassung |
| High Arctic landscapes are essentially vast cold deserts interspersed with
streams, ponds and wetlands. These landscapes may be important consumers and
sources of the greenhouse gas methane (CH4), though few measurements
exist from this region. To quantify the flux of CH4 (FCH4)
between the atmosphere and high Arctic landscapes on northern
Ellesmere Island, Canada, we made static chamber measurements over five and
three growing seasons at a desert and wetland, respectively, and eddy
covariance (EC) measurements at a wetland in 2012. Chamber measurements
revealed that, during the growing season, desert soils consumed CH4
(−1.37 ± 0.06 mg-CH4 m−2 d−1), whereas the wetland
margin emitted CH4
(+0.22 ± 0.14 mg-CH4 m−2 d−1). Desert CH4
consumption rates were positively associated with soil temperature among
years, and were similar to temperate locations, likely because of suitable
landscape conditions for soil gas diffusion. Wetland FCH4 varied
closely with stream discharge entering the wetland and hence extent of soil
saturation. Landscape-scale FCH4 measured by EC was
+1.27 ± 0.18 mg-CH4 m−2 d−1 and varied with soil
temperature and carbon dioxide flux. FCH4 measured using EC was
higher than using chambers because EC measurements incorporated a larger,
more saturated footprint of the wetland. Using EC FCH4 and
quantifying the mass of CH4 entering and exiting the wetland in stream
water, we determined that methanogenesis within wetland soils was the
dominant source of FCH4. Low FCH4 at the wetland
was likely due to a shallow organic soil layer, and thus limited carbon
resources for methanogens. Considering the prevalence of dry soils in the
high Arctic, our results suggest that these landscapes cannot be overlooked
as important consumers of atmospheric CH4. |
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