Canfield D E, Thamdrup B
Max Planck Institute for Marine Microbiology, Bremen, Germany.
Science. 1994 Dec 23;266:1973-5. doi: 10.1126/science.11540246.
Bacteria that disproportionate elemental sulfur fractionate sulfur isotopes such that sulfate is enriched in sulfur-34 by 12.6 to 15.3 per mil and sulfide is depleted in sulfur-34 by 7.3 to 8.6 per mil. Through a repeated cycle of sulfide oxidation to S0 and subsequent disproportionation, these bacteria can deplete sedimentary sulfides in sulfur-34. A prediction, borne out by observation, is that more extensive sulfide oxidation will lead to sulfides that are more depleted in sulfur-34. Thus, the oxidative part of the sulfur cycle creates circumstances by which sulfides become more depleted in sulfur-34 than would be possible with sulfate-reducing bacteria alone.
能使元素硫歧化的细菌会分馏硫同位素，使得硫酸盐中硫-34富集12.6‰至15.3‰，而硫化物中硫-34贫化7.3‰至8.6‰。通过硫化物氧化为单质硫以及随后的歧化这一重复循环，这些细菌会使沉积硫化物中的硫-34减少。一个经观察证实的预测是，更广泛的硫化物氧化会导致硫-34含量更低的硫化物。因此，硫循环的氧化部分创造了这样的条件，即硫化物在硫-34中的贫化程度比仅靠硫酸盐还原细菌时可能达到的程度更高。
