Article Figures & Data
Figures
- FIG 1
Corrosion of carbon steel coupons after 9 days exposure to cultures of Sulfurimonas sp. strain CVO or sterile medium with various initial levels of sulfide and nitrate (i.e., different nitrate-to-sulfide [N/S] ratios). (A) Average general corrosion rates determined by weight loss of 1-cm by 1-cm carbon steel coupons. Error bars represent the standard deviation from the results from nine coupons from triplicate incubations. (B) Maximum pit depth after 9 days measured on duplicate X52 carbon steel coupons.
- FIG 2
(A) Images obtained by white-light interferometry showing pitting corrosion of X52 carbon steel coupons (corrosion products removed). The color scale indicates depth of individual pits. (B) Energy-dispersive X-ray (EDX) microanalysis of corrosion crust deposited on the surface of carbon steel coupons used for weight loss corrosion analysis. High sulfur content (+S, yellow) was detected on the surface and was absent or markedly reduced in mineral structures (–S, white).
- FIG 3
(A to C) Concentration changes of sulfur and nitrogen species in cultures of strain CVO at a nitrate-to-sulfide (N/S) ratio of 2.5. (D) Corrosion rate time series in cultures of Sulfurimonas sp. strain CVO at an N/S ratio of 2.5. See Fig. S5 for weight loss profile and sterile controls.
- FIG 4
Corrosion rates determined by weight loss of carbon steel coupons after 9 days of exposure to sterile anaerobic medium with different concentrations of N and/or S species. Metal coupons were either directly exposed to individual species (white bars) or precorroded in sulfide-containing medium to create an iron sulfide (FeS) layer prior to the 9-day experimental incubations (black bars). Biogenic S0 refers to zero-valent sulfur harvested from cultures of strain CVO. For reference, the dashed line indicates the highest corrosion rate observed in incubations with strain CVO.
- FIG 5
Schematic illustration of biotic and abiotic reactions at carbon steel surfaces in the presence of active soNRB, sulfide, and nitrate. Thickness of arrows indicates relative contribution to corrosion of the individual reactions. Dashed arrows indicate potential catalytic effects. Shift of pH and redox potential, as observed during growth of strain CVO in corrosion experiments, is also depicted. See Discussion for details.
Additional Files
Supplemental material
- Supplemental file 1 -
Depth profile of cleaned carbon steel coupons (Fig. S1); scanning electron micrographs (Fig. S2); X-ray diffraction patterns (Fig. S3); changes in concentrations of sulfur and nitrogen compounds (Fig. S4); weight loss profiles and corrosion rate profiles (Fig. S5); corrosion rates (Fig. S6); amounts of nitrite consumed and amounts of ammonium formed (Fig. S7); experimental setup (Fig. S8); key parameters of individual incubations of Sulfurimonas sp. strain CVO (Table S1); elemental composition determined by EDX of corrosion products formed on carbon steel coupons during incubations with Sulfurimonas sp. strain CVO (Table S2).
PDF, 8.8M
- Supplemental file 1 -
