Evaluating the role of microbial sulfate reduction in the early Archean using quadruple isotope systematics
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Article history: Microscopic pyrites with lo Received 25 August 2008 Received in revised form 2 January 2009 Accepted 6 January 2009 Available online 15 February 2009 Editor: R.W. Carlson
منابع مشابه
The Archean sulfur cycle and the early history of atmospheric oxygen.
The isotope record of sedimentary sulfides can help resolve the history of oxygen accumulation into the atmosphere. We measured sulfur isotopic fractionation during microbial sulfate reduction up to 88 degrees C and show how sulfate reduction rate influences the preservation of biological fractionations in sediments. The sedimentary sulfur isotope record suggests low concentrations of seawater ...
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Mass-independent sulfur isotope signatures are observed in Archean and early Paleoproterozoic sedimentary sulfate and sulfide minerals, and provide the most robust constraints on early atmospheric oxygen levels. Smaller mass-independent sulfur isotope anomalies are observed in ice cores and interpreted as a tracer of stratospheric volcanic loading. Photochemistry of sulfur dioxide (SO 2) has be...
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The phylogenetic positions of sulfate-reducing organisms, as revealed from comparisons of small-subunit ribosomal RNA (SSU rRNA), are spread over both the Archaeal and Bacterial domains, though when they evolved is uncertain. The lowbranching positions of some of these groups on the Tree of Life have inspired the hypothesis that the metabolic innovation of microbial sulfate reduction is of grea...
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Microbial sulfate reduction can impart strong sulfur isotope fractionation by preferentially using the lighter 32SO2! 4 over the heavier 34SO 4 . The magnitude of fractionation depends on a number of factors, including ambient concentrations of sulfate and electron donors. Sulfur isotope compositions in sedimentary rocks thus facilitate reconstruction of past environmental conditions, such as s...
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تاریخ انتشار 2009