Encyclopedia of Geobiology

2011 Edition
| Editors: Joachim Reitner, Volker Thiel


  • John F. Stolz
  • Ronald S. Oremland
Reference work entry
DOI: https://doi.org/10.1007/978-1-4020-9212-1_180


Selenium, element 34, is a metalloid in row VIB of the periodic table. The main oxidation states are selenide (−2), elemental selenium (0), selenite (+4), and selenate (+6). Selenate and selenite are found in the oxic zone, while Se(0) is more abundant in the anoxic zone. Although hydrogen selenide may be produced by microorganisms, it is highly toxic. Se(-II) is more often found as organoselenium in the form of selenoproteins. The common methylated species (e.g., dimethylselenide, dimethyldiselenide) are volatile. Selenium can be a substitute for sulfur and is often found as metal selenide (e.g., Clausthalite, Crookesite). Selenium occurs in eight stable isotopes, the most common of which are Se80 (∼50%) and Se78 (∼24%), and nine radioactive isotopes.

The microbial oxidation of selenium is a slow process, whereas the dissimilatory reduction of selenate via selenite to Se(0) is rapid (Dowdle and Oremland, 1998). Selenate and selenite may also methylated, and Se(0) can be...


Isotope Fractionation Formate Dehydrogenase Thiopurine Methyltransferase Oxic Zone Hydrogen Selenide 
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  1. Dowdle, P. R., and Oremland, R. S., 1998. Microbial oxidation of elemental selenium in soil slurries and bacterial cultures. Environmental Science & Technology, 32, 3749–3755.CrossRefGoogle Scholar
  2. Herbel, M. J., Johnson, T. M., Oremland, R. S., and Bullen, T. D., 2000. Fractionation of selenium isotopes during bacterial respiratory reduction of selenium oxyanions. Geochimica et Cosmochimica Acta, 64, 3701–3709.CrossRefGoogle Scholar
  3. Oremland, R. S., Herbel, M. J., Switzer Blum, J., Langley, S., Beveridge, T. J., Sutto, T., Ajayan, P. M., Ellis, A., and Curran, S., 2004. Structural and spectral features of selenium nanospheres formed by Se-respiring bacteria. Applied and Environmental Microbiology, 70, 52–60.CrossRefGoogle Scholar
  4. Stolz, J. F., Basu, P., Santini, J. M., and Oremland, R. S., 2006. Selenium and arsenic in microbial metabolism. Annual Review of Microbiology, 60, 107–130.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • John F. Stolz
    • 1
  • Ronald S. Oremland
    • 2
  1. 1.Bayer School of Natural & Environmental Sciences Department of Biological SciencesDuquesne UniversityPittsburghUSA
  2. 2.Water Resources Division, MS 480United States Geological SurveyMenlo ParkUSA