Dissimilatory Bacterial Reduction of Al-Substituted Goethite in Subsurface Sediments
Microbiologic reduction of the 0.2-2.0 mm size fraction of an Atlantic coastal plain sediment (Eatontown) was investigated using a dissimilatory Fe(III)-reducing bacterium (Shewanella putrefaciens, strain CN32) to evaluate mineralogic controls on the rate and extent of Fe(III) reduction and resulting distribution of biogenic Fe(II). Mössbauer spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) was used to show that the sedimentary Fe(III) oxide was Al-substituted goethite (11-17% Al) that existed as 1-5 mm aggregates of indistinct morphology. Bioreduction experiments were performed in two buffers [HCO3-, 1,4-piperazinediethansulfonic acid (PIPES)] both without and with 2,6-anthraquinone disulfonate (AQDS), an electron shuttle. The production of biogenic Fe(II) and the distribution of Al (aqueous and sorbed) were followed over time, as was formation of Fe(II) biominerals and physical/chemical changes to the goethite.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1025702
- Report Number(s):
- PNNL-SA-33140; KP1301010
- Journal Information:
- Geochimica et Cosmochimica Acta, 65(17):2913-2924, Journal Name: Geochimica et Cosmochimica Acta, 65(17):2913-2924 Journal Issue: 17 Vol. 65; ISSN 0016-7037
- Country of Publication:
- United States
- Language:
- English
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