气候变化领域集成服务门户(CCPortal): Distinguishing between old and modern permafrost sources in the northeast Siberian land-shelf system with compound-specific δ2H analysis

CCPortal

DOI	10.5194/tc-11-1879-2017
	Distinguishing between old and modern permafrost sources in the northeast Siberian land-shelf system with compound-specific δ2H analysis
	Vonk J.E.; Tesi T.; Bröder L.; Holmstrand H.; Hugelius G.; Andersson A.; Dudarev O.; Semiletov I.; Gustafsson Ö.
发表日期	2017
ISSN	19940416
卷号	11 期号:4
英文摘要	Pleistocene ice complex permafrost deposits contain roughly a quarter of the organic carbon (OC) stored in permafrost (PF) terrain. When permafrost thaws, its OC is remobilized into the (aquatic) environment where it is available for degradation, transport or burial. Aquatic or coastal environments contain sedimentary reservoirs that can serve as archives of past climatic change. As permafrost thaw is increasing throughout the Arctic, these reservoirs are important locations to assess the fate of remobilized permafrost OC. We here present compound-specific deuterium (δ2H) analysis on leaf waxes as a tool to distinguish between OC released from thawing Pleistocene permafrost (ice complex deposits; ICD) and from thawing Holocene permafrost (from near-surface soils). Bulk geochemistry (%OC; δ13C; %total nitrogen, TN) was analyzed as well as the concentrations and δ2H signatures of long-chain n-alkanes (C21 to C33) and mid- to long-chain n-alkanoic acids (C16 to C30) extracted from both ICD-PF samples (n Combining double low line 9) and modern vegetation and O-horizon (topsoil-PF) samples (n Combining double low line 9) from across the northeast Siberian Arctic. Results show that these topsoil-PF samples have higher %OC, higher OC/TN values and more depleted δ13C-OC values than ICD-PF samples, suggesting that these former samples trace a fresher soil and/or vegetation source. Whereas the two investigated sources differ on the bulk geochemical level, they are, however, virtually indistinguishable when using leaf wax concentrations and ratios. However, on the molecular isotope level, leaf wax biomarker δ2H values are statistically different between topsoil PF and ICD PF. For example, the mean δ2H value of C29 n-alkane was -246±13‰ (mean±SD) for topsoil PF and -280±12‰ for ICD PF. With a dynamic isotopic range (difference between two sources) of 34 to 50‰; the isotopic fingerprints of individual, abundant, biomarker molecules from leaf waxes can thus serve as endmembers to distinguish between these two sources. We tested this molecular δ2H tracer along with another source-distinguishing approach, dual-carbon (δ13C-Δ14C) isotope composition of bulk OC, for a surface sediment transect in the Laptev Sea. Results show that general offshore patterns along the shelf-slope transect are similar, but the source apportionment between the approaches vary, which may highlight the advantages of either. This study indicates that the application of δ2H leaf wax values has potential to serve as a complementary quantitative measure of the source and differential fate of OC thawed out from different permafrost compartments.
学科领域	biomarker; concentration (composition); deuterium; geochemistry; Holocene; isotopic composition; leaf; organic carbon; permafrost; Pleistocene; remobilization; source apportionment; thawing; topsoil; wax; Arctic; Arctic Ocean; Laptev Sea; Siberia
语种	英语
scopus关键词	biomarker; concentration (composition); deuterium; geochemistry; Holocene; isotopic composition; leaf; organic carbon; permafrost; Pleistocene; remobilization; source apportionment; thawing; topsoil; wax; Arctic; Arctic Ocean; Laptev Sea; Siberia
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/119358
作者单位	Department of Earth Sciences, Vrije Universiteit Amsterdam, Amsterdam, Netherlands; Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm, Sweden; ISMAR Institute of Marine Sciences, Bologna, Italy; Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden; Department of Physical Geography, Stockholm University, Stockholm, Sweden; Pacific Oceanological Institute FEBRAS, Vladivostok, Russian Federation; Tomsk National Research Polytechnical University, Tomsk, Russian Federation; International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, United States
推荐引用方式 GB/T 7714	Vonk J.E.,Tesi T.,Bröder L.,et al. Distinguishing between old and modern permafrost sources in the northeast Siberian land-shelf system with compound-specific δ2H analysis[J],2017,11(4).
APA	Vonk J.E..,Tesi T..,Bröder L..,Holmstrand H..,Hugelius G..,...&Gustafsson Ö..(2017).Distinguishing between old and modern permafrost sources in the northeast Siberian land-shelf system with compound-specific δ2H analysis.Cryosphere,11(4).
MLA	Vonk J.E.,et al."Distinguishing between old and modern permafrost sources in the northeast Siberian land-shelf system with compound-specific δ2H analysis".Cryosphere 11.4(2017).