Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
The Cryosphere, 9, 737-752, 2015
https://doi.org/10.5194/tc-9-737-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
20 Apr 2015
Dissolved organic carbon (DOC) in Arctic ground ice
M. Fritz1, T. Opel1, G. Tanski1, U. Herzschuh1,2, H. Meyer1, A. Eulenburg1, and H. Lantuit1,2 1Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Department of Periglacial Research, Potsdam, Germany
2University of Potsdam, Institute of Earth and Environmental Sciences, Potsdam, Germany
Abstract. 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.

Citation: Fritz, M., Opel, T., Tanski, G., Herzschuh, U., Meyer, H., Eulenburg, A., and Lantuit, H.: Dissolved organic carbon (DOC) in Arctic ground ice, The Cryosphere, 9, 737-752, https://doi.org/10.5194/tc-9-737-2015, 2015.
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Short summary
Ground ice in permafrost has not, until now, been considered to be a source of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC) and other elements that are important for ecosystems and carbon cycling. Ice wedges in the Arctic Yedoma region hold 45.2 Tg DOC (Tg = 10^12g), 33.6 Tg DIC and a freshwater reservoir of 4200 km³. Leaching of terrestrial organic matter is the most relevant process of DOC sequestration into ground ice.
Ground ice in permafrost has not, until now, been considered to be a source of dissolved organic...
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