Microbial U Isotope Fractionation Depends on the U(VI) Reduction Rate

Basu, Anirban; Wanner, Christoph; Johnson, Thomas M; Lundstrom, Craig C; Sanford, Robert A; Sonnenthal, Eric L; Boyanov, Maxim I; Kemner, Kenneth M (2020). Microbial U Isotope Fractionation Depends on the U(VI) Reduction Rate. Environmental science & technology, 54(4), pp. 2295-2303. ACS Publications 10.1021/acs.est.9b05935

[img] Text
BasuEtAlES&T'20.pdf - Published Version
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (1MB) | Request a copy
[img]
Preview
Text
BasuEtAl_Accepted.pdf - Accepted Version
Available under License Publisher holds Copyright.

Download (2MB) | Preview

U isotope fractionation may serve as an accurate proxy for U(VI) reduction in both modern and ancient environments, if the systematic controls on the magnitude of fractionation (ε) are known. We model the effect of U(VI) reduction kinetics on U isotopic fractionation during U(VI) reduction by a novel Shewanella isolate, Shewanella sp. (NR), in batch incubations. The measured ε values range from 0.96 ± 0.16 to 0.36 ± 0.07‰ and are strongly dependent on the U(VI) reduction rate. The ε decreases with increasing reduction rate constants normalized by cell density and initial U(VI). Reactive transport simulations suggest that the rate dependence of ε is due to a two-step process, where diffusive transport of U(VI) from the bulk solution across a boundary layer is followed by enzymatic reduction. Our results imply that the spatial decoupling of bulk U(VI) solution and enzymatic reduction should be taken into account for interpreting U isotope data from the environment.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences
08 Faculty of Science > Institute of Geological Sciences > Rock-Water Interaction

UniBE Contributor:

Wanner, Christoph

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

0013-936X

Publisher:

ACS Publications

Language:

English

Submitter:

Christoph Wanner

Date Deposited:

04 Feb 2020 14:15

Last Modified:

08 Jan 2021 02:30

Publisher DOI:

10.1021/acs.est.9b05935

BORIS DOI:

10.7892/boris.139672

URI:

https://boris.unibe.ch/id/eprint/139672

Actions (login required)

Edit item Edit item
Provide Feedback