Research ArticleGEOLOGY

Remobilization of dormant carbon from Siberian-Arctic permafrost during three past warming events

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Science Advances  16 Oct 2020:
Vol. 6, no. 42, eabb6546
DOI: 10.1126/sciadv.abb6546
  • Fig. 1 Paleoenvironment of the LGM (20 ka B.P.) with the location of core 31-PC (red star; SWERUS-C3 expedition 2014).

    Bathymetry of the Arctic and Northern Pacific Ocean are from GEBCO 2014. The beige shade marks the additional-to-present permafrost-covered land surface during the LGM, purple marks the area flooded during the EH (11 to 7.6 ka B.P.; based on shelf bathymetry and global sea-level rise) (5, 31), and dark gray marks the modern land surface. The orange color indicates the distribution of ICDs in periglacial regions of Siberia and Alaska (10). LIS, Laurentide Ice Sheet; BS, Bering Sea; CS, Chukchi Sea; ESS, East Siberian Sea; LS, Laptev Sea; BKIS, Barents-Kara Sea Ice Sheet; OS, Sea of Okhotsk; NSI, New Siberian Islands. Red triangles indicate the location of cores described in previous studies on the Arctic shelves, the 4-PC (13), GC-58 (17), and PC-23 (11). Yellow triangles indicate the location of cores located in the Pacific realm; the cores SO202-18-3/6, SO201-2-114KL, and SO201-2-12KL in the Bering Sea (18); as well as the cores SO178-13-6 and LV28-4-4 in the Sea of Okhotsk (14).

  • Fig. 2 Bulk carbon characteristics and biomarkers in sediments of core 31-PC over the past 27 ka B.P., which covers the Dansgaard-Oeschger event 3 (DO-3), the cold Last Glacial Maximum (LGM), the Heinrich Stadial 1 (HS-1), the Bølling-Allerød (BA) warm interstadial, the cold Younger Dryas (YD) stadial, and the warm Holocene/Interglacial [including the EH Preboreal (PB)].

    The curves show (A) the North Greenland Ice Core Project (NGRIP) δ18O record (39), (B) the total OC flux to the 31-PC location (g m−2 year−1), (C) δ13C of OC, and (D) the predepositional 14C age of OC. It further shows (E) terrestrial biomarker fluxes of lignin phenols, HMW n-alkanes and n-alkanoic acids (μg m−2 year−1), as well as (F) fractions of the total OC flux (g m−2 year−1) and the 1σ uncertainties based on statistical source apportionment of OC mobilized from the two permafrost pools ICDs and permafrost active layer (AL). *The range bar indicates extent of possible delay in arrival of the PF-C signal from EH warming, due to the large increase of cross-shelf transport times (text S2) (40).

  • Fig. 3 Lignin source diagnostics of terrigenous material in the 31-PC (80 samples) compared with previously studied sediment cores from the Siberian Shelf 4-PC (13), GC-58 (17), and PC-23 (11), as well as coastal ICD, AL permafrost (32), and Lena river particulate OC (25).

    The size of the 31-PC circles is proportional to the magnitude of the respective lignin flux (0.01 to 6.6 mg year−1 m−2). The abundance ratio of syringyl over vanillyl (S/V) indicates contributions of angiosperm compared to gymnosperm plants, and the ratio between cinnamyl and vanillyl (C/V) distinguishes between woody (e.g., stems) and nonwoody (e.g. leaves) plant tissues (24).

  • Fig. 4 The observational record of permafrost OC fluxes to sediment cores of the ESAS compared with (A) the Greenland ice core δ18O record (39), (B) the atmospheric CO2 concentration (7), and (C) Northern Hemisphere temperature rise (6).

    The other panels show transport time corrected permafrost OC fluxes from ICDs to the 31-PC (D) and (uncorrected) peaks of ICD fluxes to the ESAS cores (E) 4-PC (13), PC-23 (11), and GC-58 (17). Furthermore, permafrost OC release by AL is shown for (F) the 31-PC and the other cores from the ESAS (G). The abbreviated time intervals are the DO-3, the LGM, the HS-1, the BA warm interstadial, the cold YD stadial, and the warm Holocene/Interglacial (including the EH PB). *The shown fluxes of the 31-PC include a correction for cross-shelf transport times due to increasing offshore distance with global sea-level rise during the EH (text S2). The ICD and AL fluxes indicate the minimum estimate, while pale peak shadows show the possible maximum estimate.

Supplementary Materials

  • Supplementary Materials

    Remobilization of dormant carbon from Siberian-Arctic permafrost during three past warming events

    Jannik Martens, Birgit Wild, Francesco Muschitiello, Matt O’Regan, Martin Jakobsson, Igor Semiletov, Oleg V. Dudarev, Örjan Gustafsson

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    • Texts S1 and S2
    • Figs. S1 to S5
    • Tables S1 to S5

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