Sulfur isotope distribution in solfataras, yellowstone national park.

Sulfur isotope data on hydrogen sulfide, native sulfur, and sulfates from acid hot-spring areas at Yellowstone National Park suggest that hydrogen sulfide oxidizes to sulfur abiologically, whereas sulfur undergoes biological oxidation to sulfuric acid. An exception occurs at Mammoth Hot Springs where hydrogen sulfide apparently undergoes biochemical oxidation to sulfur.