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标题：Carbonaceous material export from Siberian permafrost tracked across the Arctic Shelf using Raman spectroscopy
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作者：Robert B. Sparkes ; Melissa Maher ; Jerome Blewett 等
期刊名称：The Cryosphere
印刷版ISSN：1994-0416
电子版ISSN：1994-0424
出版年度：2018
卷号：12
期号：10
页码：3293-3309
DOI：10.5194/tc-12-3293-2018
出版社：Copernicus Publications
摘要：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.