Subsurface Biogeochemical Research. Click to return to home page.
Department of Energy Office of Science. Click to visit main DOE SC site.

U.S. Department of Energy Office of Biological and Environmental Research

Searchable Research Highlights for
Subsurface Biogeochemical Research Program



How Sulfur Affects Chemistry of Iron in the Environment
Published: May 30, 2014
Posted: January 06, 2017

Substantial amounts of iron are present in many subsurface environments. This element has a significant effect on both the biogeochemical cycling of carbon and the fate and transport of trace environmental contaminants, because it is readily transformed among several reactive species. The interactions of subsurface iron with various naturally occurring bacteria have a major influence on its environmental impacts, but these interactions are not well understood. Scientists at Argonne National Laboratory and three partner universities have identified a key role for sulfur in how bacteria affect the speciation of subsurface iron. They determined that bacteria unable to reduce ferric iron directly under alkaline conditions can do so indirectly. The bacteria do this by reducing elemental sulfur to sulfide ion, which then reduces the ferric iron in the goethite to ferrous iron. In addition, this ferrous iron can reduce other metal species such as uranyl ion, thus affecting their solubility. The researchers determined that this process is common in alkaline environments such aquifers, especially those in arid regions. This new understanding of this environmental role of iron will enable progress in a wide range of areas, from modeling of potential carbon capture systems to understanding speciation of contaminants such as uranium and arsenic.

References: Flynn, T. M., E. J. O’Loughlin, B. Mishra, T. J. DiChristina, and K. M. Kemner. 2014. “Sulfur-Mediated Electron Shuttling During Bacterial Iron Reduction,”, Science 344, 1039-42. DOI: 10.1126/science.1252066. (Reference link)

Friedrich, M. W., and K. W. Finster. 2014. “How Sulfur Beats Iron,” Science 344, 974-75. DOI: 10.1126/science.1255442. (Reference link)

Contact: Roland F. Hirsch, SC-23.2, roland.hirsch@science.doe.gov, 301-903-9009.

Topic Areas:

  • Research Area: Carbon Cycle, Biosequestration
  • Research Area: Subsurface Biogeochemical Research
  • Research Area: Microbes and Communities
  • Mission Science: Climate
  • Mission Science: Environmental Cleanup

Division: SC-23.1 Climate and Environmental Sciences Division, BER

 

Recent Highlights

Nov 21, 2017
CrunchFlow Receives 2017 R&D 100 Award
Powerful software simulates how chemical reactions occur and change as fluids travel underground. [more...]

Nov 01, 2017
Assembly of Microbial Communities Affects Biogeochemistry
Dispersal varies the relationship between microbial communities and biogeochemical function.
more...]

Sep 29, 2017
How Bacteria Produce Manganese Oxide Nanoparticles
Structural characterization of bacterial enzyme complex sheds light on manganese biomineralizati [more...]

Sep 05, 2017
A Regional Model for Uranium Redox State and Mobility in the Environment
Redox variable sediments mediate uranium mobility in the upper Colorado River Basin. [more...]

Aug 26, 2017
New Approach to Characterize Natural Organic Matter in Belowground Sediments
Efforts to characterize carbon stored in sediments below 1 meter are critical for understanding t [more...]