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| Titel |
Widespread release of old carbon across the Siberian Arctic echoed by its large rivers |
| VerfasserIn |
Ö. Gustafsson, B. E. Dongen, J. E. Vonk, O. V. Dudarev, I. P. Semiletov |
| 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. 6 ; Nr. 8, no. 6 (2011-06-30), S.1737-1743 |
| Datensatznummer |
250005967
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| Publikation (Nr.) |
 copernicus.org/bg-8-1737-2011.pdf |
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| Zusammenfassung |
| Over decadal-centennial timescales, only a few mechanisms in the
carbon-climate system could cause a massive net redistribution of carbon
from land and ocean systems to the atmosphere in response to climate
warming. The largest such climate-vulnerable carbon pool is the old organic
carbon (OC) stored in Arctic permafrost (perennially frozen) soils. Climate
warming, both predicted and now observed to be the strongest globally in the
Eurasian Arctic and Alaska, causes thaw-release of old permafrost carbon
from local tundra sites. However, a central challenge for the assessment of
the general vulnerability of this old OC pool is to deduce any signal
integrating its release over larger scales. Here we examine radiocarbon
measurements of molecular soil markers exported by the five Great
Russian-Arctic Rivers (Ob, Yenisey, Lena, Indigirka and Kolyma), employed as
natural integrators of carbon release processes in their watersheds. The
signals held in estuarine surface sediments revealed that average
radiocarbon ages of n-alkanes increased east-to-west from 6400 yr BP in
Kolyma to 11 400 yr BP in Ob. This is consistent with westwards trends of
both warmer climate and more degraded organic matter as indicated by the
ratio of high molecular weight (HMW) n-alkanoic acids to HMW n-alkanes. The
dynamics of Siberian permafrost can thus be probed via the
molecular-radiocarbon signal as carried by Arctic rivers. Old permafrost
carbon is at present vulnerable to mobilization over continental scales.
Climate-induced changes in the radiocarbon fingerprint of released
permafrost carbon will likely depend on changes in both permafrost coverage
and Arctic soil hydraulics. |
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