Article Figures & Data
Figures
- Fig. 1.
Distribution of Fe(II), particulate Fe(III) oxides, O2, and bacteria in two Fe(II)-oxidizing cultures. (B and D) TW1 and TW2 cultures, respectively. (A and C) Abiotic controls for the cultures shown in B and D, respectively. Note that Fe(II) profiles determined by densitometry in diffusion probes are confounded by the presence of Fe(III) compounds in the probe (see text). O2profiles are averages of triplicate measurements. (A and B) Representative Fe(II) profile from triplicate profiles obtained from a single probe. (C and D) Fe(II) profiles are averages of single measurements from probes in triplicate cultures. No error bars are shown. Bacterial numbers in A and B are averages of counts on triplicate slides from a single culture (A and B) or averages of counts from a single slide from each of triplicate cultures (C and D); error bars were omitted for clarity. In control cultures, bacterial numbers were never significantly different from zero.
- Fig. 2.
Relationship between O2 penetration depth and the base of the oxide band in control and TW1-inoculated cultures. Data represent averages of triplicate cultures, and error bars show 95% confidence intervals.
- Fig. 3.
Comparison of soluble Fe(II) concentration determined by microprobe technique and Ferrozine in control (A) and TW1-inoculated (B) cultures. Ferrozine data are averages of triplicate cores, and error bars represent the 95% confidence interval; they are omitted if smaller than the size of the symbol. For the microprobes, a single representative profile from three different measurements from a single probe is shown.
- Fig. 4.
Photo of K3Fe(CN)6-fixed microprobes from control and Fe(II)-oxidizing organism-inoculated cultures shown in Fig. 1. Superimposed black bars indicate the positioning of Fe(III) oxide bands, measured independently, in the cultures; white bars denote oxic zones. Arrows indicate the approximate position of the bacterial number peaks (live cultures only). Standards were photographed under different light conditions and may not be directly comparable with the microprobes.
- Fig. 5.
Fe(II) and Fe(III) in whole medium samples and diffusion probes. (A) Comparison among probes and the medium in TW2 and control cultures; (B) comparison between washed and unwashed probes from TW2 and control cultures. Data represent averages of triplicate cultures, and error bars show 95% confidence intervals.
