Sea-air exchange patterns along the central and outer East Siberian Arctic Shelf as inferred from continuous CO2, stable isotope, and bulk chemistry measurements

Christoph Humborg, Marc C. Geibel, Leif G. Anderson, Göran Björk, Carl Magnus Mörth, Marcus Sundbom, Brett F. Thornton, Barbara Deutsch, Erik Gustafsson, Bo Gustafsson, Jörgen Ek, Igor Semiletov

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2 Citations (Scopus)

Abstract

This large-scale quasi-synoptic study gives a comprehensive picture of sea-air CO2 fluxes during the melt season in the central and outer Laptev Sea (LS) and East Siberian Sea (ESS). During a 7 week cruise we compiled a continuous record of both surface water and air CO2 concentrations, in total 76,892 measurements. Overall, the central and outer parts of the ESAS constituted a sink for CO2, and we estimate a median uptake of 9.4 g C m−2 yr−1 or 6.6 Tg C yr−1. Our results suggest that while the ESS and shelf break waters adjacent to the LS and ESS are net autotrophic systems, the LS is a net heterotrophic system. CO2 sea-air fluxes for the LS were 4.7 g C m−2 yr−1, and for the ESS we estimate an uptake of 7.2 g C m−2 yr−1. Isotopic composition of dissolved inorganic carbon (δ13CDIC and δ13CCO2) in the water column indicates that the LS is depleted in δ13CDIC compared to the Arctic Ocean (ArcO) and ESS with an offset of 0.5‰ which can be explained by mixing of δ13CDIC-depleted riverine waters and 4.0 Tg yr−1 respiration of OCter; only a minor part (0.72 Tg yr−1) of this respired OCter is exchanged with the atmosphere. Property-mixing diagrams of total organic carbon and isotope ratio (δ13CSPE-DOC) versus dissolved organic carbon (DOC) concentration diagram indicate conservative and nonconservative mixing in the LS and ESS, respectively. We suggest land-derived particulate organic carbon from coastal erosion as an additional significant source for the depleted δ13CDIC.

Original languageEnglish
Pages (from-to)1173-1191
Number of pages19
JournalGlobal Biogeochemical Cycles
Volume31
Issue number7
DOIs
Publication statusPublished - 1 Jul 2017

Fingerprint

Organic carbon
Isotopes
stable isotope
air
Air
Water
Carbon Isotopes
Fluxes
Surface waters
Erosion
Carbon
sea
dissolved organic carbon
Chemical analysis
diagram
coastal erosion
dissolved inorganic carbon
particulate organic carbon
shelf break
total organic carbon

Keywords

  • air-sea flux
  • carbon
  • carbon isotope
  • climate change
  • respiration
  • Siberian Shelf

ASJC Scopus subject areas

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

Cite this

Sea-air exchange patterns along the central and outer East Siberian Arctic Shelf as inferred from continuous CO2, stable isotope, and bulk chemistry measurements. / Humborg, Christoph; Geibel, Marc C.; Anderson, Leif G.; Björk, Göran; Mörth, Carl Magnus; Sundbom, Marcus; Thornton, Brett F.; Deutsch, Barbara; Gustafsson, Erik; Gustafsson, Bo; Ek, Jörgen; Semiletov, Igor.

In: Global Biogeochemical Cycles, Vol. 31, No. 7, 01.07.2017, p. 1173-1191.

Research output: Contribution to journalArticle

Humborg, C, Geibel, MC, Anderson, LG, Björk, G, Mörth, CM, Sundbom, M, Thornton, BF, Deutsch, B, Gustafsson, E, Gustafsson, B, Ek, J & Semiletov, I 2017, 'Sea-air exchange patterns along the central and outer East Siberian Arctic Shelf as inferred from continuous CO2, stable isotope, and bulk chemistry measurements', Global Biogeochemical Cycles, vol. 31, no. 7, pp. 1173-1191. https://doi.org/10.1002/2017GB005656
Humborg, Christoph ; Geibel, Marc C. ; Anderson, Leif G. ; Björk, Göran ; Mörth, Carl Magnus ; Sundbom, Marcus ; Thornton, Brett F. ; Deutsch, Barbara ; Gustafsson, Erik ; Gustafsson, Bo ; Ek, Jörgen ; Semiletov, Igor. / Sea-air exchange patterns along the central and outer East Siberian Arctic Shelf as inferred from continuous CO2, stable isotope, and bulk chemistry measurements. In: Global Biogeochemical Cycles. 2017 ; Vol. 31, No. 7. pp. 1173-1191.
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AU - Björk, Göran

AU - Mörth, Carl Magnus

AU - Sundbom, Marcus

AU - Thornton, Brett F.

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