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| Titel |
Methane fluxes measured by eddy covariance and static chamber techniques at a temperate forest in central Ontario, Canada |
| VerfasserIn |
J. M. Wang, J. G. Murphy, J. A. Geddes, C. L. Winsborough, N. Basiliko, S. C. Thomas |
| 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 ; 10, no. 6 ; Nr. 10, no. 6 (2013-06-28), S.4371-4382 |
| Datensatznummer |
250018318
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| Publikation (Nr.) |
 copernicus.org/bg-10-4371-2013.pdf |
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| Zusammenfassung |
| Methane flux measurements were carried out at a temperate
forest (Haliburton Forest and Wildlife Reserve) in central Ontario
(45°17´11´´ N, 78°32´19´´ W) from June to October 2011.
Continuous measurements were made by an off-axis integrated cavity output
spectrometer that measures methane (CH4) at 10 Hz sampling rates.
Fluxes were calculated from the gas measurements in conjunction with wind
data collected by a 3-D sonic anemometer using the eddy covariance (EC)
method. Observed methane fluxes showed net uptake of CH4 over the
measurement period with an average uptake flux (±standard deviation
of the mean) of −2.7 ± 0.13 nmol m−2 s−1. Methane fluxes
showed a seasonal progression with average rates of uptake increasing from
June through September and remaining high in October. This pattern was
consistent with a decreasing trend in soil moisture content at the monthly
timescale. On the diurnal timescale, there was evidence of increased uptake
during the day, when the mid-canopy wind speed was at a maximum. These
patterns suggest that substrate supply of CH4 to methanotrophs, and in
certain cases hypoxic soil conditions supporting methanogenesis in low-slope
areas, drives the observed variability in fluxes. A network of soil static
chambers used at the tower site showed reasonable agreement with the
seasonal trend and overall magnitude of the eddy covariance flux
measurements. This suggests that soil-level microbial processes, and not
abiological leaf-level CH4 production, drive overall CH4 dynamics
in temperate forest ecosystems such as Haliburton Forest. |
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