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An electrochemical study of the influence of Marinobacter aquaeolei on the alteration of hydrothermal chalcopyrite (CuFeS2) and pyrite (FeS2) under circumneutral conditions

An electrochemical study of the influence of Marinobacter aquaeolei on the alteration of hydrothermal chalcopyrite (CuFeS2) and pyrite (FeS2) under circumneutral conditions
An electrochemical study of the influence of Marinobacter aquaeolei on the alteration of hydrothermal chalcopyrite (CuFeS2) and pyrite (FeS2) under circumneutral conditions
Pyrite and chalcopyrite are the two most abundant sulphides observed in seafloor hydrothermal systems. The alteration of sulphides is primarily controlled by reactions on the mineral surfaces and Fe(II)-oxidising bacteria closely related to Marinobacter aquaeolei are thought to play a major role in iron oxidation under circumneutral conditions. We assessed the influence of M. aquaeolei on the electroactivity of FeS2 and CuFeS2 minerals under circumneutral conditions. Samples for the experiments were obtained from the Trans-Atlantic Geotraverse (TAG) hydrothermal mound (field), 26 °N on the Mid-Atlantic Ridge and Ireland (CuFeS2)]. The experimental approach relied on voltammetry and scanning electrochemical microscopy (SECM). The tip-substrate voltammetry mode of SECM was found to be particularly suitable to probe the major redox processes of those minerals and permitted an assessment of the microorganisms influence on these processes. M. aquaeolei was found to enhance FeS2 and CuFeS2 oxidation, particularly under suboxic conditions. M. aquaeolei also significantly enhances Fe dissolution under oxic circumneutral conditions but suppresses the dissolution of most other elements compared to abiotic conditions. Under abiotic conditions the surfaces of the minerals are rapidly passivated when oxygen is available; while addition of M. aquaeolei significantly hinders the passivation of chalcopyrite, no passivation of the pyrite surface is observed. This study demonstrates the ability of Marinobacter aquaeolei to enhance oxidation of FeS2 and CuFeS2 under circumneutral conditions and supports the involvement of Marinobacter species in weathering reactions on the seafloor and the control of the ultimate fate of sulphide deposits.

scanning electrochemical microscopy, secm, voltammetry, alteration, hydrothermal, chalcopyrite, pyrite, marinobacter aquaeolei
0149-0451
373-382
Müller, M.
d806c137-1e7e-48c9-93a9-fea684d8f67e
Mills, R.A.
a664f299-1a34-4b63-9988-1e599b756706
Pearce, R.B.
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Milton, J.A.
9e183221-d0d4-4ddb-aeba-0fdde9d31230
Statham, P.J.
51458f15-d6e2-4231-8bba-d0567f9e440c
Lloyd, J.R.
c353222d-35d0-48d9-a94c-6ab000395e97
Mujahid, A.
203890f0-ef94-4991-900b-8dc32d740f87
Denuault, G.
5c76e69f-e04e-4be5-83c5-e729887ffd4e
Müller, M.
d806c137-1e7e-48c9-93a9-fea684d8f67e
Mills, R.A.
a664f299-1a34-4b63-9988-1e599b756706
Pearce, R.B.
7d772b25-3ad0-4909-9a96-3a1a8111bc2f
Milton, J.A.
9e183221-d0d4-4ddb-aeba-0fdde9d31230
Statham, P.J.
51458f15-d6e2-4231-8bba-d0567f9e440c
Lloyd, J.R.
c353222d-35d0-48d9-a94c-6ab000395e97
Mujahid, A.
203890f0-ef94-4991-900b-8dc32d740f87
Denuault, G.
5c76e69f-e04e-4be5-83c5-e729887ffd4e

Müller, M., Mills, R.A., Pearce, R.B., Milton, J.A., Statham, P.J., Lloyd, J.R., Mujahid, A. and Denuault, G. (2014) An electrochemical study of the influence of Marinobacter aquaeolei on the alteration of hydrothermal chalcopyrite (CuFeS2) and pyrite (FeS2) under circumneutral conditions. Geomicrobiology Journal, 31 (5), 373-382. (doi:10.1080/01490451.2012.711430).

Record type: Article

Abstract

Pyrite and chalcopyrite are the two most abundant sulphides observed in seafloor hydrothermal systems. The alteration of sulphides is primarily controlled by reactions on the mineral surfaces and Fe(II)-oxidising bacteria closely related to Marinobacter aquaeolei are thought to play a major role in iron oxidation under circumneutral conditions. We assessed the influence of M. aquaeolei on the electroactivity of FeS2 and CuFeS2 minerals under circumneutral conditions. Samples for the experiments were obtained from the Trans-Atlantic Geotraverse (TAG) hydrothermal mound (field), 26 °N on the Mid-Atlantic Ridge and Ireland (CuFeS2)]. The experimental approach relied on voltammetry and scanning electrochemical microscopy (SECM). The tip-substrate voltammetry mode of SECM was found to be particularly suitable to probe the major redox processes of those minerals and permitted an assessment of the microorganisms influence on these processes. M. aquaeolei was found to enhance FeS2 and CuFeS2 oxidation, particularly under suboxic conditions. M. aquaeolei also significantly enhances Fe dissolution under oxic circumneutral conditions but suppresses the dissolution of most other elements compared to abiotic conditions. Under abiotic conditions the surfaces of the minerals are rapidly passivated when oxygen is available; while addition of M. aquaeolei significantly hinders the passivation of chalcopyrite, no passivation of the pyrite surface is observed. This study demonstrates the ability of Marinobacter aquaeolei to enhance oxidation of FeS2 and CuFeS2 under circumneutral conditions and supports the involvement of Marinobacter species in weathering reactions on the seafloor and the control of the ultimate fate of sulphide deposits.

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More information

e-pub ahead of print date: 30 July 2012
Published date: 2014
Keywords: scanning electrochemical microscopy, secm, voltammetry, alteration, hydrothermal, chalcopyrite, pyrite, marinobacter aquaeolei
Organisations: Geochemistry, Ocean and Earth Science, Engineering Science Unit, Paleooceanography & Palaeoclimate

Identifiers

Local EPrints ID: 346280
URI: http://eprints.soton.ac.uk/id/eprint/346280
ISSN: 0149-0451
PURE UUID: 8517816d-bed9-4507-9f43-2669a845c5f4
ORCID for R.A. Mills: ORCID iD orcid.org/0000-0002-9811-246X
ORCID for G. Denuault: ORCID iD orcid.org/0000-0002-8630-9492

Catalogue record

Date deposited: 17 Dec 2012 14:41
Last modified: 20 Jul 2019 01:22

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Contributors

Author: M. Müller
Author: R.A. Mills ORCID iD
Author: R.B. Pearce
Author: J.A. Milton
Author: P.J. Statham
Author: J.R. Lloyd
Author: A. Mujahid
Author: G. Denuault ORCID iD

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