Organic sulfur was integral to the Archean sulfur cycle
Organic sulfur was integral to the Archean sulfur cycle
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DOI：
10.1038/s41467-019-12396-y
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发表时间：
2019-10-07
影响因子：
16.6
通讯作者：
Katsev, Sergei
中科院分区：
文献类型：
--
作者：
Fakhraee, Mojtaba;Katsev, Sergei
早期地球的化学成分被广泛地从硫化物沉积岩的元素和同位素组成中推断出来，这些硫化物沉积岩被认为是通过海水硫酸盐的还原在全球范围内形成的，或者是从热液供应的硫化物中形成的。在这里，我们认为，在缺氧的太古代海洋中，黄铁矿可以形成在没有环境硫酸盐的活细胞内所含的有机硫。硫化物可以通过还原硫化合物的矿化或有机源亚硫酸盐的还原来产生。反应输运模型表明，硫酸盐浓度高达几十微摩尔，有机硫将支持20至100%的沉积黄铁矿沉淀和高达75%的微生物硫还原。这一结果为太古代硫化物中δ S-3（4）的低幅度提供了另一种解释，并提出了硫酸盐稀缺延迟异化硫酸盐还原演化直到2.7 Ga左右初始海洋氧化的可能性。
The chemistry of the Early Earth is widely inferred from the elemental and isotopic compositions of sulfidic sedimentary rocks, which are presumed to have formed globally through the reduction of seawater sulfate or locally from hydrothermally supplied sulfide. Here we argue that, in the anoxic Archean oceans, pyrite could form in the absence of ambient sulfate from organic sulfur contained within living cells. Sulfides could be produced through mineralization of reduced sulfur compounds or reduction of organic-sourced sulfite. Reactive transport modeling suggests that, for sulfate concentrations up to tens of micromolar, organic sulfur would have supported 20 to 100% of sedimentary pyrite precipitation and up to 75% of microbial sulfur reduction. The results offer an alternative explanation for the low range of delta S-3(4) in Archean sulfides, and raise a possibility that sulfate scarcity delayed the evolution of dissimilatory sulfate reduction until the initial ocean oxygenation around 2.7 Ga.