Multimolecular tracers of terrestrial carbon transfer across the pan-Arctic: 14C characteristics of sedimentary carbon components and their environmental controls

Xiaojuan Feng, Örjan Gustafsson, R. Max Holmes, Jorien E. Vonk, Bart E. Van Dongen, Igor P. Semiletov, Oleg V. Dudarev, Mark B. Yunker, Robie W. Macdonald, Lukas Wacker, Daniel B. Montluçon, Timothy I. Eglinton

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Distinguishing the sources, ages, and fate of various terrestrial organic carbon (OC) pools mobilized from heterogeneous Arctic landscapes is key to assessing climatic impacts on the fluvial release of carbon from permafrost. Through molecular 14C measurements, including novel analyses of suberin- and/or cutin-derived diacids (DAs) and hydroxy fatty acids (FAs), we compared the radiocarbon characteristics of a comprehensive suite of terrestrial markers (including plant wax lipids, cutin, suberin, lignin, and hydroxy phenols) in the sedimentary particles from nine major arctic and subarctic rivers in order to establish a benchmark assessment of the mobilization patterns of terrestrial OC pools across the pan-Arctic. Terrestrial lipids, including suberin-derived longer-chain DAs (C24,26,28), plant wax FAs (C24,26,28), and n-alkanes (C27,29,31), incorporated significant inputs of aged carbon, presumably from deeper soil horizons. Mobilization and translocation of these "old" terrestrial carbon components was dependent on nonlinear processes associated with permafrost distributions. By contrast, shorter-chain (C16,18) DAs and lignin phenols (as well as hydroxy phenols in rivers outside eastern Eurasian Arctic) were much more enriched in 14C, suggesting incorporation of relatively young carbon supplied by runoff processes from recent vegetation debris and surface layers. Furthermore, the radiocarbon content of terrestrial markers is heavily influenced by specific OC sources and degradation status. Overall, multitracer molecular 14C analysis sheds new light on the mobilization of terrestrial OC from arctic watersheds. Our findings of distinct ages for various terrestrial carbon components may aid in elucidating fate of different terrestrial OC pools in the face of increasing arctic permafrost thaw.

Original languageEnglish
Pages (from-to)1855-1873
Number of pages19
JournalGlobal Biogeochemical Cycles
Volume29
Issue number11
DOIs
Publication statusPublished - 1 Nov 2015

Keywords

  • compound-specific radiocarbon analysis
  • diacids
  • lignin
  • pan-arctic rivers
  • plant wax lipids
  • terrestrial carbon markers

ASJC Scopus subject areas

  • Global and Planetary Change
  • Atmospheric Science
  • Environmental Science(all)
  • Environmental Chemistry

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  • Cite this

    Feng, X., Gustafsson, Ö., Holmes, R. M., Vonk, J. E., Van Dongen, B. E., Semiletov, I. P., Dudarev, O. V., Yunker, M. B., Macdonald, R. W., Wacker, L., Montluçon, D. B., & Eglinton, T. I. (2015). Multimolecular tracers of terrestrial carbon transfer across the pan-Arctic: 14C characteristics of sedimentary carbon components and their environmental controls. Global Biogeochemical Cycles, 29(11), 1855-1873. https://doi.org/10.1002/2015GB005204