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Large sulfur isotope fractionation by bacterial sulfide oxidation

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Science Advances  24 Jul 2019:
Vol. 5, no. 7, eaaw1480
DOI: 10.1126/sciadv.aaw1480
  • Fig. 1 Compilation of 34ε or the difference between δ34S of sulfate and sulfide (Δ34SSO4−HS−) from this study (red bar), as well as those reported by previous studies (black bars) of microbial sulfide oxidizers that can oxidize sulfide to sulfate (table S1).

    The solid bar for DA represents the average 34ε measured for cells growing in the exponential phase, whereas the broken line is when the maximum Δ34SSO4−HS− obtained when cells in stationary phase are transferred to fresh medium. The gray background outlines the range observed in past studies. When the product is enriched in 32S relative to the substrate, the values are negative, whereas when the product is enriched in 34S relative to the substrate, the values are positive. Only experiments with sulfide as substrate are included in this compilation.

  • Table 1 Growth parameters and sulfur isotope effects during the growth of DA on sulfide and nitrate in three replicate experiments.

    Substrate consumption ratios, yields, and cell-specific consumption rates highlight the differences in nitrate and sulfide consumption. Calculated 34ε values varied depending on whether the substrate (sulfide) or product (sulfate) was used. Uncertainty was propagated from regression uncertainties (see the Supplementary Materials).

    ExperimentGrowth rate
    (day−1)
    Substrate
    consumption ratio
    Yield estimates
    [mol C (mol NO3)−1]
    Cell-specific consumption rates
    (fmol cell−1 day−1)
    Sulfur
    isotope
    enrichment
    factor*
    kσHS:NO3σYsσYcσHSσNO3σ34εσ
    10.140.011.420.030.840.060.200.019.80.56.90.3+13.10.7
    20.250.021.410.050.840.090.390.039.00.86.40.6
    30.240.031.450.030.900.070.360.029.41.16.40.8+12.00.5

    *34ε reported in this table is based on Rayleigh enrichment of the substrate pool. See Supplementary Materials and Materials and Methods.

    Supplementary Materials

    • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/7/eaaw1480/DC1

      Fig. S1. Growth experiment 1.

      Fig. S2. Growth experiment 2.

      Fig. S3. Growth experiment 3.

      Fig. S4. Plot of δ34S as a function of ln(f) for the sulfide or [f/(1 − f)]ln(f) for the sulfate for experiments 1 and 3 (see Materials and Methods).

      Fig. S5. Plot of δ34S as a function of the sulfide consumed (f).

      Fig. S6. Water (black bars) and equilibrium sulfate (gray bars) δ18O in respective water enrichment experiments A to D.

      Table S1. Compilation of sulfur isotope enrichments during MSO used for the construction of Fig. 1 and additional information on growth conditions.

      References (4353)

    • Supplementary Materials

      This PDF file includes:

      • Fig. S1. Growth experiment 1.
      • Fig. S2. Growth experiment 2.
      • Fig. S3. Growth experiment 3.
      • Fig. S4. Plot of δ34S as a function of ln(f) for the sulfide or f/(1 − f)ln(f) for the sulfate for experiments 1 and 3 (see Materials and Methods).
      • Fig. S5. Plot of δ34S as a function of the sulfide consumed (f).
      • Fig. S6. Water (black bars) and equilibrium sulfate (gray bars) δ18O in respective water enrichment experiments A to D.
      • Table S1. Compilation of sulfur isotope enrichments during MSO used for the construction of Fig. 1 and additional information on growth conditions.
      • References (4353)

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