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The Cryosphere An interactive open-access journal of the European Geosciences Union
The Cryosphere, 11, 2305-2327, 2017
https://doi.org/10.5194/tc-11-2305-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Special issue editorial
05 Oct 2017
Discovery and characterization of submarine groundwater discharge in the Siberian Arctic seas: a case study in the Buor-Khaya Gulf, Laptev Sea
Alexander N. Charkin1,2, Michiel Rutgers van der Loeff3, Natalia E. Shakhova2,4, Örjan Gustafsson5, Oleg V. Dudarev1,2, Maxim S. Cherepnev2, Anatoly N. Salyuk1, Andrey V. Koshurnikov6, Eduard A. Spivak1, Alexey Y. Gunar6, Alexey S. Ruban2, and Igor P. Semiletov1,2,4 1Pacific Oceanological Institute (POI), Far Eastern Branch of Russian Academy of Sciences Russian Academy of Sciences (FEBRAS), Vladivostok, Russia
2Department of Geology and Minerals Prospecting, National Research Tomsk Polytechnic University, Tomsk, Russia
3Department of Geochemistry, Alfred-Wegener Institute, Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
4International Arctic Research Center (IARC), University of Alaska, Fairbanks, USA
5Dept. of Environmental Science and Analytical Chemistry, and the Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
6Department of Geocryology, Moscow State University, Moscow, Russia
Abstract. It has been suggested that increasing terrestrial water discharge to the Arctic Ocean may partly occur as submarine groundwater discharge (SGD), yet there are no direct observations of this phenomenon in the Arctic shelf seas. This study tests the hypothesis that SGD does exist in the Siberian Arctic Shelf seas, but its dynamics may be largely controlled by complicated geocryological conditions such as permafrost. The field-observational approach in the southeastern Laptev Sea used a combination of hydrological (temperature, salinity), geological (bottom sediment drilling, geoelectric surveys), and geochemical (224Ra, 223Ra, 228Ra, and 226Ra) techniques. Active SGD was documented in the vicinity of the Lena River delta with two different operational modes. In the first system, groundwater discharges through tectonogenic permafrost talik zones was registered in both winter and summer. The second SGD mechanism was cryogenic squeezing out of brine and water-soluble salts detected on the periphery of ice hummocks in the winter. The proposed mechanisms of groundwater transport and discharge in the Arctic land-shelf system is elaborated. Through salinity vs. 224Ra and 224Ra / 223Ra diagrams, the three main SGD-influenced water masses were identified and their end-member composition was constrained. Based on simple mass-balance box models, discharge rates at sites in the submarine permafrost talik zone were 1. 7 × 106 m3 d−1 or 19.9 m3 s−1, which is much higher than the April discharge of the Yana River. Further studies should apply these techniques on a broader scale with the objective of elucidating the relative importance of the SGD transport vector relative to surface freshwater discharge for both water balance and aquatic components such as dissolved organic carbon, carbon dioxide, methane, and nutrients.

Citation: Charkin, A. N., Rutgers van der Loeff, M., Shakhova, N. E., Gustafsson, Ö., Dudarev, O. V., Cherepnev, M. S., Salyuk, A. N., Koshurnikov, A. V., Spivak, E. A., Gunar, A. Y., Ruban, A. S., and Semiletov, I. P.: Discovery and characterization of submarine groundwater discharge in the Siberian Arctic seas: a case study in the Buor-Khaya Gulf, Laptev Sea, The Cryosphere, 11, 2305-2327, https://doi.org/10.5194/tc-11-2305-2017, 2017.
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This study tests the hypothesis that SGD exists in the Siberian Arctic shelf seas, but its dynamics may be largely controlled by complicated geocryological conditions such as permafrost. The permafrost cements rocks, forms a confining bed, and as a result makes it difficult for the groundwater escape to the shelf surface. However, the discovery of subterranean outcrops of groundwater springs in the Buor-Khaya Gulf are clear evidence that a groundwater flow system exists in the environment.
This study tests the hypothesis that SGD exists in the Siberian Arctic shelf seas, but its...
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