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| Titel |
Modeling the impediment of methane ebullition bubbles by seasonal lake ice |
| VerfasserIn |
S. Greene, K. M. Walter Anthony, D. Archer, A. Sepulveda-Jauregui, K. Martinez-Cruz |
| 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 (2014-12-08), S.6791-6811 |
| Datensatznummer |
250117717
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| Publikation (Nr.) |
 copernicus.org/bg-11-6791-2014.pdf |
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| Zusammenfassung |
| Microbial methane (CH4) ebullition (bubbling) from anoxic lake
sediments comprises a globally significant flux to the atmosphere, but
ebullition bubbles in temperate and polar lakes can be trapped by winter ice
cover and later released during spring thaw. This "ice-bubble storage"
(IBS) constitutes a novel mode of CH4 emission. Before bubbles are
encapsulated by downward-growing ice, some of their CH4 dissolves into
the lake water, where it may be subject to oxidation. We present field
characterization and a model of the annual CH4 cycle in Goldstream
Lake, a thermokarst (thaw) lake in interior Alaska. We find that summertime
ebullition dominates annual CH4 emissions to the atmosphere. Eighty
percent of CH4 in bubbles trapped by ice dissolves into the lake water
column in winter, and about half of that is oxidized. The ice growth rate
and the magnitude of the CH4 ebullition flux are important controlling
factors of bubble dissolution. Seven percent of annual ebullition CH4
is trapped as IBS and later emitted as ice melts. In a future warmer
climate, there will likely be less seasonal ice cover, less IBS, less
CH4 dissolution from trapped bubbles, and greater CH4 emissions
from northern lakes. |
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