| Summary: | The Arctic region contains a huge amount of organic carbon, referred to commonly as the "Arctic Carbon Hyper Pool", within the Arctic Ocean sedimentary basin. The Russian Arctic shelf acts as an estuary of the Great Siberian Rivers. This area has the highest documented rates of coastal sedimentation with annual accumulation rates of about 10x106 t C org year-, which approximately equals the amount of sediment accumulated over the entire pelagic zone of the World Ocean. Due to the specific features of sedimentation and lithogenesis in this area, much of this organic carbon survives decomposition, and is buried within seabed sediments. These sediments are annually ("offshore" permafrost) or seasonally frozen, representing a substantial reservoir of potentially labile organic carbon. Global warming in the Arctic region is predicted to be substantial, and possibly rapid, in next few decades. Upon permafrost melting, the old carbon stored therein will be reintroduced into the modern carbon biogeochemical cycle, possibly acting as a strong source of methane to the overlying water and potentially the atmosphere. Additionally, extremely large amounts of more ancient (Pleistocene) methane are trapped as gas hydrates within and beneath the permafrost. This project to elucidate the present and future methane flux potential of sediments and permafrost in regions of the East Siberian Arctic Shelf. As a result of global warming, seafloor permafrost along the East Siberian Arctic Shelf may experience a pronounced change in thermal regime. Increased temperature may affect permafrost in several ways, ultimately leading to its degradation and enhanced CH4 release. This international, interdisciplinary research team determined the distribution and stability of permafrost on the East Siberian Arctic Shelf and evaluated this area as a methane source to the Arctic region. Cores from ten locations were obtained using dry drilling techniques. Thermal and biogeochemical data obtained from the boreholes/sediment cores were used as input to numerical models, which were developed to describe the thermodynamic and biogeochemical aspects of permafrost methane dynamics. NSF-OPP ARC-0909546: Colloborative research: "Degrading Offshore Permafrost and Arctic Hydrates as a Current and Potential Source of Methane on the Siberian Arctic Shelf" List of project papers: Shakhova, N., Semiletov, I., Leifer, I., , Sergienko, V., Salyuk, A., Kosmach, D., Chernikh D., Stubbs, Ch., Nicolsky D., Tumskoy V., and Ö. Gustafsson (2013). Ebullition and storm-induced methane release from the East Siberian Arctic Shelf, Nature Geosciences, DOI:10.1038/ NGEO2007. Chuvilin, E.M., Bukhanov, B.A., Tumskoy, V.E., Shakhova, N.E., Dudarev, O.E., and I.P. Semiletov (2013). Thermal conductivity of bottom sediments in the region of Buor Khaya Bay (Shelf of the Laptev Sea), Earth Cryosphere, 17(2), 32-40. Semiletov, I.P., Shakhova, N.E., Pipko, I.I., Pugach, S.P., Charkin, A.N., Dudarev, O.V., Kosmach, D.A., and S. Nishino (2013). Space-time dynamics of carbon and environmental parameters related to carbon dioxide emissions in the Buor-Khaya Bay of the Laptev Sea, Biogeosciences, 10, 5977-5996, www.biogeosciences.net/10/5997/2013/doi:10.5194/bg-10-5977-2013. Nicolsky, D.J., Romanovsky, V.E., Romanovskii, N., Kholodov, A.L., Shakhova, N.E., and I. Semiletov (2012). Modeling sub-sea permafrost in the East Siberian Arctic Shelf: The Laptev Sea Region, Journal of Geophysical Research, doi:10.1029/2012JF002358 Nicolsky, D., and N. Shakhova (2010). Modeling sub-sea permafrost in the East-Siberian Arctic Shelf: the Dmitry Laptev Strait, Env. Res. Lett.,5, doi:10.1088/1748-9326/5/1/015006. Semiletov, I.P., Shakhova, N. E., Sergienko, V.I., Pipko, I.I., and O. Dudarev (2012). On carbon transport and fate in the East Siberian Arctic Land-Shelf-Atmosphere System, Environment Research Letters, 7, doi:10.1088/1748-9326/7/1/015201 Semiletov, I.P., Pipko, I.I., Shakhova, N.E., Dudarev, O.V., Pugach, S.P., Charkin, A.N., McRoy, C.P., Kosmach, D., and Ö. Gustafsson (2011). Carbon transport by the Lena River from its headwaters to the Arctic Ocean, with emphasis on fluvial input of terrestrial particulate organic carbon vs. carbon transport by coastal erosion, Biogeosciences, 8, 2407-2426. Karlsson, E.S., Charkin, A., Dudarev, O., Semiletov, I., Vonk, J.E., Sánchez-García, L., Andersson, A., and Ö. Gustafsson (2011). Carbon isotopes and lipid biomarker investigation of sources, transport and degradation of terrestrial organic matter in the Buor-Khaya Bay, SE Laptev Sea, Biogeosciences, 8, 1865-1879, doi:10.5194/bg-8-1865-2011 Shakhova, N., Nicolsky, D., and I. Semiletov (2009). Current state of sub-sea permafrost on the East-Siberian Shelf: Testing of modeling results by observational data, Doklady Earth Science 429 (2), 1518-1521. Semiletov, I., Shakhova, N., Lobkovsky, L., Dmitrevsky, N., Dudarev, O., Tumskoy, V., Grigoriev, M., Ananiev, R., Charkin, A., Koshurnikov, A., and E. Chuvilin . Degradation offshore permafrost as a source of methane on the East Siberian Arctic shelf, Science, in preparation
|
|---|