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| Titel |
CO2 and CH4 in sea ice from a subarctic fjord under influence of riverine input |
| VerfasserIn |
O. Crabeck, B. Delille, D. Thomas, N.-X. Geilfus, S. Rysgaard, J.-L. Tison |
| 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. 23 ; Nr. 11, no. 23 (2014-12-01), S.6525-6538 |
| Datensatznummer |
250117700
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| Publikation (Nr.) |
 copernicus.org/bg-11-6525-2014.pdf |
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| Zusammenfassung |
| We present the CH4 concentration [CH4], the partial pressure of
CO2 (pCO2) and the total gas content in bulk sea ice from subarctic,
land-fast sea ice in the Kapisillit fjord, Greenland. Fjord systems are
characterized by freshwater runoff and riverine input and based on δ18O data, we show that > 30% of the surface water
originated from periodic river input during ice growth. This resulted in
fresher sea-ice layers with higher gas content than is typical from marine
sea ice. The bulk ice [CH4] ranged from 1.8 to 12.1 nmol L−1,
which corresponds to a partial pressure ranging from 3 to 28 ppmv. This is
markedly higher than the average atmospheric methane content of 1.9 ppmv.
Evidently most of the trapped methane within the ice was contained inside
bubbles, and only a minor portion was dissolved in the brines. The bulk ice
pCO2 ranged from 60 to 330 ppmv indicating that sea ice at temperatures
above −4 °C is undersaturated compared to the atmosphere (390 ppmv).
This study adds to the few existing studies of CH4 and CO2
in sea ice, and we conclude that subarctic seawater can be a sink for atmospheric
CO2, while being a net source of CH4. |
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