FIG 6.

Geomicrobiological model of the Aha watershed profile. The model shows the roles of the major S- and Fe-related bacteria identified in the current study. The color of the arrows indicates the extent of the physiochemical parameters or geochemical process. A transition from saturated to transparent colors in a color ribbon indicates a decrease in the corresponding environmental factor from zone 1 to zone 4 and vice versa. Abbreviations: FeOB, Fe(II)-oxidizing bacteria; FeRB, Fe(III)-reducing bacteria; SOB, sulfur-oxidizing bacteria; SRB, sulfate-reducing bacteria; Fetot: total Fe; PPT, precipitation.