Fig. 4: Cell-specific sulfate reduction.

Cell abundance (gray bars) and relative abundance (yellow dots) of sulfate-reducing bacteria (SRB) (a, c) and cell-specific sulfate reduction rates (SRR, mean of all treatments) (b, d) in Samail Ophiolite and Coast Range Ophiolite fluids. Wells are grouped according to their classification by pH and fluid origin (light red background: gabbro/peridotite contact fluids; light blue background: alkaline peridotite fluids, dark blue background: hyperalkaline peridotite fluids, green background: meteoric/surface water).