Research ArticleCLIMATOLOGY

Mountain glaciation drives rapid oxidation of rock-bound organic carbon

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Science Advances  04 Oct 2017:
Vol. 3, no. 10, e1701107
DOI: 10.1126/sciadv.1701107
  • Fig. 1 The western Southern Alps, New Zealand.

    (A) Watersheds for the central part of the study area where glacier area varies most, with watershed boundaries marked in white. The black line is the Alpine Fault trace. Image is from Landsat ETM (Enhanced Thematic Mapper) (31 December 2002), shown to illustrate glacial coverage. The watershed-averaged dissolved Re concentration, [Re]diss (pmol liter−1), is shown as the circle size, and the shading reflects the percentage watershed area with glaciers (23). Inset shows the location of the study area on South Island, New Zealand. (B) Positive relationship between watershed-averaged [Re]diss and the percentage of the watershed area covered by glaciers (n = 13, r = 0.93, r2 = 0.87, P < 0.001). Gray whiskers are ±2 SE on the mean [Re]diss values.

  • Fig. 2 Dissolved Re yield in mountain watersheds around the world draining sedimentary rocks as a function of suspended sediment yield.

    Dissolved Re yields (mol km−2 year−1) have been normalized to river bed material Re concentration ([Re]BM, pmol kg−1) to account for lithological variability between watersheds (table S6). Gray whiskers show ±50% of the values. Gray symbols represent watersheds with <0.05% of their area covered by glaciers, with the power law best fit to data shown by the black line and the 95% confidence intervals shown in gray [y = (4.1 ± 3.4 × 10−9)x(0.7 ± 0.1), r2 = 0.82, P < 0.001, n = 12]. Blue symbols represent watersheds with glaciers covering >1% of the watershed area, and purple symbols represent watersheds with the highest coverage of glaciers (>40%).

  • Fig. 3 Net carbon balance due to erosion and weathering in the western Southern Alps.

    Two watersheds with contrasting glacial coverage area are shown: the Whataroa (9.7% glacier coverage) and the Waiho (57.6% glacier coverage). The CO2 release to the atmosphere by OCpetro weathering (this study; from dissolved Re measurements) is shown alongside the CO2 drawdown by erosion and burial of biospheric particulate OC (POCbiosphere) (22) and silicate weathering (20, 24).

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/10/e1701107/DC1

    fig. S1. Weathered colluvium from the western Southern Alps.

    fig. S2. Dissolved major ion concentrations in the western Southern Alps.

    table S1. River bed materials.

    table S2. Re and OCpetro in weathered colluvium.

    table S3. Major ion and Re concentration data for water samples from the Southern Alps, New Zealand.

    table S4. Western Southern Alps watershed average data and dissolved Re yield estimates.

    table S5. Hydrological data for watersheds with river gauging stations.

    table S6. Global watershed averaged Re measurements from mountain rivers draining sedimentary rocks.

    Reference (6266)

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. Weathered colluvium from the western Southern Alps.
    • fig. S2. Dissolved major ion concentrations in the western Southern Alps.
    • table S1. River bed materials.
    • table S2. Re and OCpetro in weathered colluvium.
    • table S3. Major ion and Re concentration data for water samples from the Southern Alps, New Zealand.
    • table S4. Western Southern Alps watershed average data and dissolved Re yield estimates.
    • table S5. Hydrological data for watersheds with river gauging stations.
    • table S6. Global watershed averaged Re measurements from mountain rivers draining sedimentary rocks.
    • Reference (62–66)

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