FIG. 3.

Production of sulfate during growth of Metallosphaera sp. strain MK1 in the presence of pyrite and elemental S⁰ (pH 3, 65°C, 0.005% yeast extract). The growth medium contained aqueous sulfate at an initial concentration of 3 mM, and controls revealed that there was little change in sulfate in the absence of microbial growth. The error bars indicate standard errors (n = 3).