Dissolved organic carbon (DOC) in Arctic ground ice, from northwest Canada, east Siberia, and Alaska


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 (mean: 9.6 mg/L). 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 km**3. 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.

This study was undertaken in the Helmholtz Young Investigators Group 'COPER' - Coastal permafrost erosion, organic carbon and nutrient release in the Arctic nearshore zone (Helmholtz Association grant no. VH-NG-801 to Hugues Lantuit).http://www.awi.de/forschung/nachwuchsgruppen/coper.html

Supplement to: Fritz, Michael; Opel, Thomas; Tanski, George; Herzschuh, Ulrike; Meyer, Hanno; Eulenburg, Antje; Lantuit, Hugues (2015): Dissolved organic carbon (DOC) in Arctic ground ice. The Cryosphere, 9(2), 737-752

DOI https://doi.org/10.1594/PANGAEA.846074
Related Identifier https://doi.org/10.5194/tc-9-737-2015
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.846074
Creator Fritz, Michael ORCID logo; Opel, Thomas ORCID logo; Tanski, George ORCID logo; Herzschuh, Ulrike ORCID logo; Meyer, Hanno ORCID logo; Eulenburg, Antje ORCID logo; Lantuit, Hugues ORCID logo
Publisher PANGAEA
Publication Year 2015
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 1687 data points
Discipline Earth System Research
Spatial Coverage (-138.318W, 65.030S, 117.170E, 73.600N); Barrow, Northern Alaska; Fairbanks, Interior Alaska; Herschel Island, Yukon Territory, Canada; Komakuk Beach, Yukon Coastal Plain, Canada; Kay Point, Yukon Coast; Bol'shoy Lyakhovsky Island, New Siberian Islands; Samoylov Island, Lena Delta, Siberia; Cape Mamontov Klyk , Western Laptev Sea; Muostakh Island, Eastern Laptev Sea; Oyogos Yar coast, Dmitry Laptev Strait; Roland Bay, Yukon Coastal Plain, Canada