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| Titel |
Greenhouse gas fluxes in a drained peatland forest during spring frost-thaw event |
| VerfasserIn |
M. K. Pihlatie, R. Kiese, N. Brüggemann, K. Butterbach-Bahl, A.-J. Kieloaho, T. Laurila, A. Lohila, I. Mammarella, K. Minkkinen, T. Penttilä, J. Schönborn, T. Vesala |
| 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 ; 7, no. 5 ; Nr. 7, no. 5 (2010-05-25), S.1715-1727 |
| Datensatznummer |
250004779
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| Publikation (Nr.) |
 copernicus.org/bg-7-1715-2010.pdf |
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| Zusammenfassung |
| Fluxes of greenhouse gases (GHG) carbon dioxide (CO2), methane
(CH4) and nitrous oxide (N2O) were measured during a two month
campaign at a drained peatland forest in Finland by the eddy covariance (EC)
technique (CO2 and N2O), and automatic and manual chambers
(CO2, CH4 and N2O). In addition, GHG concentrations and soil
parameters (mineral nitrogen, temperature, moisture content) in the peat
profile were measured. The aim of the measurement campaign was to quantify
the GHG fluxes during freezing and thawing of the top-soil, a time period
with potentially high GHG fluxes, and to compare different flux measurement
methods. The forest was a net CO2 sink during the two months and the
fluxes of CO2 dominated the GHG exchange. The peat soil was a small
sink of atmospheric CH4 and a small source of N2O. Both CH4
oxidation and N2O production took place in the top-soil whereas
CH4 was produced in the deeper layers of the peat, which were unfrozen
throughout the measurement period. During the frost-thaw events of the
litter layer distinct peaks in CO2 and N2O emissions were
observed. The CO2 peak followed tightly the increase in soil
temperature, whereas the N2O peak occurred with a delay after the
thawing of the litter layer. CH4 fluxes did not respond to the thawing
of the peat soil. The CO2 and N2O emission peaks were not captured
by the manual chambers and hence we conclude that high time-resolution
measurements with automatic chambers or EC are necessary to quantify fluxes
during peak emission periods. Sub-canopy EC measurements and chamber-based
fluxes of CO2 and N2O were comparable, although the fluxes of
N2O measured by EC were close to the detection limit of the system. We
conclude that if fluxes are high enough, i.e. greater than 5–10 μg N m−2 h−1,
the EC method is a good alternative to measure N2O
and CO2 fluxes at ecosystem scale, thereby minimizing problems with
chamber enclosures and spatial representativeness of the measurements. |
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