Carbonaceous material export from Siberian permafrost tracked across the Arctic Shelf using Raman spectroscopy

• Published in: The Cryosphere
• Main Authors: Sparkes, Robert B., Maher, Melissa, Blewett, Jerome, Selver, Ayça Doğrul, Gustafsson, Orjan, Semiletov, Igor P., van Dongen, Bart E.
• Other Authors: Mühendislik Fakültesi, orcid:0000-0003-0756-0150, orcid:0000-0003-1189-142X
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Gesellschaft MBH 2018
• Subjects: Terrigenous Organic-Matter; Black Carbon; Laptev Sea; Old Carbon; Terrestrial; Ocean; Degradation; Sediments; Graphite; River; Arctic; Indigirka; Kolyma; black carbon; laptev; permafrost; Swedish Polar Research Secretariat; Siberia
• Online Access: https://hdl.handle.net/20.500.12462/5441; https://doi.org/10.5194/tc-12-3293-2018

Selver, Ayça Doğrul (Balikesir Author) Warming-induced erosion of permafrost from Eastern Siberia mobilises large amounts of organic carbon and delivers it to the East Siberian Arctic Shelf (ESAS). In this study Raman spectroscopy of carbonaceous material (CM) was used to characterise, identify and track the most recalcitrant fraction of the organic load: 1463 spectra were obtained from surface sediments collected across the ESAS and automatically analysed for their Raman peaks. Spectra were classified by their peak areas and widths into disordered, intermediate, mildly graphitised and highly graphitised groups and the distribution of these classes was investigated across the shelf. Disordered CM was most prevalent in a permafrost core from Kurungnakh Island and from areas known to have high rates of coastal erosion. Sediments from outflows of the Indigirka and Kolyma rivers were generally enriched in intermediate CM. These different sediment sources were identified and distinguished along an E-W transect using their Raman spectra, showing that sediment is not homogenised on the ESAS. Distal samples, from the ESAS slope, contained greater amounts of highly graphitised CM compared to the rest of the shelf, attributable to degradation or, more likely, winnowing processes offshore. The presence of all four spectral classes in distal sediments demonstrates that CM degrades much more slowly than lipid biomarkers and other traditional tracers of terrestrial organic matter and shows that alongside degradation of the more labile organic matter component there is also conservative transport of carbon across the shelf toward the deep ocean. Thus, carbon cycle calculations must consider the nature as well as the amount of carbon liberated from thawing permafrost and other erosional settings. NERC - NE/I024798/1 - NE/P006221/1 MMU studentship MMU-EERC research grant Swedish Research Council (VR) 621-2007-4631 621-2013-5297 621-2004-4039 Swedish Research Council (VR) (Distinguished Professors Grant) 2017-01601 European Research Council (ERC-AdG CC-TOP project) 695331 Government of the Russian Federation 14.Z50.31.0012 Knut and Alice Wallenberg Foundation Far Eastern Branch of the Russian Academy of Sciences US National Oceanic and Atmospheric Administration (OAR Climate Program Office) NA08OAR4600758 Russian Foundation of Basic Research 08-05-13572 08-05-00191-a 07-05-00050a Swedish Polar Research Secretariat Nordic Council of Ministers US National Science Foundation OPP ARC 0909546