Early Archaean microorganisms preferred elemental sulfur, not sulfate | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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  Early Archaean microorganisms preferred elemental sulfur, not sulfate

Publication Type:

Journal Article

Source:

Science, Volume 317, Issue 5844, p.1534-1537 (2007)

ISBN:

0036-8075

Keywords:

OCEAN; DISPROPORTIONATION; ATMOSPHERE; MECHANISM; EVOLUTION; SULPHATE

Abstract:

<p>
Microscopic sulfides with low S-34/S-32 ratios in marine sulfate deposits from the 3490-million-year-old Dresser Formation, Australia, have been interpreted as evidence for the presence of early sulfate-reducing organisms on Earth. We show that these microscopic sulfides have a massin-dependently fractionated sulfur isotopic anomaly (Delta S-33) that differs from that of their host sulfate (barite). These microscopic sulfides could not have been produced by sulfate-reducing microbes, nor by abiologic processes that involve reduction of sulfate. Instead, we interpret the combined negative delta S-34 and positive Delta S-33 signature of these microscopic sulfides as evidence for the early existence of organisms that disproportionate elemental sulfur.</p>

Notes:

SciencePhilippot, Pascal Van Zuilen, Mark Lepot, Kevin Thomazo, Christophe Farquhar, James Van Kranendonk, Martin J. 33 AMER ASSOC ADVANCEMENT SCIENCE