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| Titel |
Isotopic fractionation during soil uptake of atmospheric hydrogen |
| VerfasserIn |
A. Rice, A. Dayalu, P. Quay, R. Gammon |
| 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 ; 8, no. 3 ; Nr. 8, no. 3 (2011-03-23), S.763-769 |
| Datensatznummer |
250005576
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| Publikation (Nr.) |
 copernicus.org/bg-8-763-2011.pdf |
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| Zusammenfassung |
| Soil uptake of atmospheric hydrogen (H2) and the associated hydrogen
isotope effect were studied using soil chambers in a Western Washington
second-growth coniferous forest. Chamber studies were conducted during both
winter and summer seasons to account for large natural variability in soil
moisture content (4–50%) and temperature (6–22 °C). H2 deposition
velocities were found to range from 0.01–0.06 cm s−1 with an average of
0.033 ± 0.008 cm s−1 (95% confidence interval). Consistent with
prior studies, deposition velocities were correlated with soil moisture
below 20% soil moisture content during the summer season. During winter,
there was considerable variability observed in deposition velocity that was
not closely related to soil moisture. The hydrogen kinetic isotope effect
with H2 uptake was found to range from −24‰ to −109‰.
Aggregate analysis of experimental data results in an average KIE of
−57 ± 5‰ (95% CI). Some of the variability in KIE can be explained by
larger isotope effects at lower (<10%) and higher (>30%) soil
moisture contents. The measured KIE was also found to be correlated with
deposition velocity, with smaller isotope effects occurring at higher
deposition velocities. If correct, these findings will have an impact on the
interpretation of atmospheric measurements and modeling of δD of
H2. |
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