Microbially mediated kinetic sulfur isotope fractionation

Microbially mediated kinetic sulfur isotope fractionation: reactive transport modeling benchmark

Cheng, Yiwei (Lawrence Berkeley National Laboratory)
Arora, Bhavna (Lawrence Berkeley National Laboratory)
Şengör, S. Sevinç (Middle East Technical University)
Druhan, Jennifer L. (University of Illinois at Urbana Champaign)
Wanner, Christoph (University of Bern)
van Breukelen, B.M. (TU Delft Sanitary Engineering)
Steefel, Carl I. (Lawrence Berkeley National Laboratory)

2020

Microbially mediated sulfate reduction is a ubiquitous process in many subsurface systems. Isotopic fractionation is characteristic of this anaerobic process, since sulfate-reducing bacteria (SRB) favor the reduction of the lighter sulfate isotopologue (S³²O₄²⁻) over the heavier isotopologue (S³⁴O₄²⁻). Detection of isotopic shifts has been utilized as a proxy for the onset of sulfate reduction in subsurface systems such as oil reservoirs and aquifers undergoing heavy metal and radionuclide bioremediation. Reactive transport modeling (RTM) of kinetic sulfur isotope fractionation has been applied to field and laboratory studies. We developed a benchmark problem set for the simulation of kinetic sulfur isotope fractionation during microbially mediated sulfate reduction. The benchmark problem set is comprised of three problem levels and is based on a large-scale laboratory column experimental study of organic carbon amended sulfate reduction in soils from a uranium-contaminated aquifer. Pertinent processes impacting sulfur isotopic composition such as microbial sulfate reduction and iron-sulfide reactions are included in the problem set. This benchmark also explores the different mathematical formulations in the representation of kinetic sulfur isotope fractionation as employed in the different RTMs. Participating RTM codes are the following: CrunchTope, TOUGHREACT, PHREEQC, and PHT3D. Across all problem levels, simulation results from all RTMs demonstrate reasonable agreement.

Benchmark
Kinetic isotope fractionation
Microbial sulfate reduction
Reactive transport modeling
S isotopes

http://resolver.tudelft.nl/uuid:00728b7d-8386-464f-acdf-99b4b889f650

https://doi.org/10.1007/s10596-020-09988-9

2021-02-28

1420-0597

Computational Geosciences: modeling, simulation and data analysis, 25 (2021) (4), 1379-1391

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

journal article

© 2020 Yiwei Cheng, Bhavna Arora, S. Sevinç Şengör, Jennifer L. Druhan, Christoph Wanner, B.M. van Breukelen, Carl I. Steefel