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182 0 _ab
200 1 _aGDGT distributions on the East Siberian Arctic Shelf: implications for organic carbon export, burial and degradation
_fR. B. Sparkes [et al.]
203 _aText
_celectronic
300 _aTitle screen
330 _aSiberian permafrost contains a globally significant pool of organic carbon (OC) that is vulnerable to enhanced warming and subsequent release into the contemporary carbon cycle. OC release by both fluvial and coastal erosion has been reported in the region, but the behaviour of this material in the Arctic Ocean is insufficiently understood. The balance between OC deposition and degradation on the East Siberian Arctic Shelf (ESAS) influences the climate-carbon cycle feedback in this area. In this study we couple measurements of glycerol dialkyl glycerol tetraethers (GDGTs) with bulk geochemical observations to improve knowledge of the sources of OC to the ESAS, the behaviour of specific biomarkers on the shelf and the balance between delivery and removal of different carbon pools. Branched GDGT (brGDGT) concentrations were highest close to river mouths, yet low in “ice complex” permafrost deposits, supporting recent observations that brGDGTs are mostly delivered by fluvial erosion, and may be a tracer for this in complex sedimentary environments. BrGDGT concentrations and the branched and isoprenoidal tetraether (BIT) index reduced quickly offshore, demonstrating a rapid reduction in river in- fluence. Stable carbon isotope ratios changed at a different rate to the BIT index, suggesting not only that OC on the shelf is sourced from fluvial erosion but also that erosion of coastal sediments delivers substantial quantities of OC to the Arctic Ocean. A model of OC export from fluvial, coastal and marine sources is able to recreate the biomarker and bulk observations and provide estimates for the influence of fluvial and coastal OC across the whole shelf. The model shows that coastal erosion delivers 43 % of the OC and 87 % of the mineral sediment to the ESAS, but that rivers deliver 72 % of brGDGTs, indicating that brGDGTs can be used as a proxy for river-derived sediment.
461 _tBiogeosciences
463 _tVol. 12
_v[P. 3753–3768]
_d2015
610 1 _aэлектронный ресурс
610 1 _aтруды учёных ТПУ
701 1 _aSparkes
_bR. B.
701 1 _aSelver
_bA. D.
701 1 _aBischoff
_bJ.
701 1 _aTalbot
_bH. M.
701 1 _aGustafsson
_bO.
701 1 _aSemiletov
_bI. P.
_cgeographer
_cProfessor of Tomsk Polytechnic University, doctor of geographical Sciences
_f1955-
_gIgor Petrovich
_2stltpush
_3(RuTPU)RU\TPU\pers\34220
701 1 _aDudarev
_bO. V.
_cgeologist
_cresearcher of Tomsk Polytechnic University, candidate of geological and mineralogical Sciences
_f1955-
_gOleg Viktorovich
_2stltpush
_3(RuTPU)RU\TPU\pers\35379
701 1 _aDongen
_bB. E. van
712 0 2 _aНациональный исследовательский Томский политехнический университет (ТПУ)
_bИнститут природных ресурсов (ИПР)
_bКафедра геологии и разведки полезных ископаемых (ГРПИ)
_h2181
_2stltpush
_3(RuTPU)RU\TPU\col\18660
712 0 2 _aНациональный исследовательский Томский политехнический университет (ТПУ)
_bИнститут природных ресурсов (ИПР)
_bКафедра геологии и разведки полезных ископаемых (ГРПИ)
_bМеждународная научно-образовательная лаборатория изучения углерода арктических морей (МНОЛ ИУАМ)
_h7398
_2stltpush
_3(RuTPU)RU\TPU\col\20711
801 2 _aRU
_b63413507
_c20170209
_gRCR
856 4 _uhttp://dx.doi.org/10.5194/bg-12-3753-2015
942 _cCF