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| Titel |
Dissolved organic carbon (DOC) in Arctic ground ice |
| VerfasserIn |
M. Fritz, T. Opel, G. Tanski, U. Herzschuh, H. Meyer, A. Eulenburg, H. Lantuit |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 9, no. 2 ; Nr. 9, no. 2 (2015-04-20), S.737-752 |
| Datensatznummer |
250116781
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| Publikation (Nr.) |
 copernicus.org/tc-9-737-2015.pdf |
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| Zusammenfassung |
| Thermal permafrost degradation and coastal erosion in the Arctic remobilize
substantial amounts of organic carbon (OC) and nutrients which have
accumulated in late Pleistocene and Holocene unconsolidated deposits.
Permafrost vulnerability to thaw subsidence, collapsing coastlines and
irreversible landscape change are largely due to the presence of large amounts
of massive ground ice such as ice wedges. However, ground ice has not, until
now, been considered to be a source of dissolved organic carbon (DOC),
dissolved inorganic carbon (DIC) and other elements which are important for
ecosystems and carbon cycling. Here we show, using biogeochemical data from a
large number of different ice bodies throughout the Arctic, that ice wedges
have the greatest potential for DOC storage, with a maximum of
28.6 mg L−1 (mean: 9.6 mg L−1). Variation in DOC concentration
is positively correlated with and explained by the concentrations and
relative amounts of typically terrestrial cations such as Mg2+ and
K+. DOC sequestration into ground ice was more effective during the late
Pleistocene than during the Holocene, which can be explained by rapid
sediment and OC accumulation, the prevalence of more easily degradable
vegetation and immediate incorporation into permafrost. We assume that
pristine snowmelt is able to leach considerable amounts of well-preserved and
highly bioavailable DOC as well as other elements from surface sediments,
which are rapidly frozen and stored in ground ice, especially in ice wedges,
even before further degradation. We found that ice wedges in the Yedoma
region represent a significant DOC (45.2 Tg) and DIC (33.6 Tg) pool in
permafrost areas and a freshwater reservoir of 4200 km2. This study
underlines the need to discriminate between particulate OC and DOC to assess
the availability and vulnerability of the permafrost carbon pool for
ecosystems and climate feedback upon mobilization. |
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