Microbial communities acclimate to recurring changes in soil redox potential status

Authors

  • Kristen M. DeAngelis,

    Corresponding author
    1. Ecology Department, Earth Sciences Division, Lawrence Berkeley National Lab, One Cyclotron Road MS-70A3317, Berkeley, CA 94720, USA
    2. Ecosystem Sciences Division, Department of Environmental Science, Policy, and Management, 137 Mulford Hall 3114, University of California, Berkeley, CA 94720, USA
      E-mail kristen@post.harvard.edu; Tel. (+1) 510 486 5246; Fax (+1) 510 486 7152.
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  • Whendee L. Silver,

    1. Ecology Department, Earth Sciences Division, Lawrence Berkeley National Lab, One Cyclotron Road MS-70A3317, Berkeley, CA 94720, USA
    2. Ecosystem Sciences Division, Department of Environmental Science, Policy, and Management, 137 Mulford Hall 3114, University of California, Berkeley, CA 94720, USA
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  • Andrew W. Thompson,

    1. Ecosystem Sciences Division, Department of Environmental Science, Policy, and Management, 137 Mulford Hall 3114, University of California, Berkeley, CA 94720, USA
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  • Mary K. Firestone

    1. Ecology Department, Earth Sciences Division, Lawrence Berkeley National Lab, One Cyclotron Road MS-70A3317, Berkeley, CA 94720, USA
    2. Ecosystem Sciences Division, Department of Environmental Science, Policy, and Management, 137 Mulford Hall 3114, University of California, Berkeley, CA 94720, USA
    Search for more papers by this author

E-mail kristen@post.harvard.edu; Tel. (+1) 510 486 5246; Fax (+1) 510 486 7152.

Summary

Rapidly fluctuating environmental conditions can significantly stress organisms, particularly when fluctuations cross thresholds of normal physiological tolerance. Redox potential fluctuations are common in humid tropical soils, and microbial community acclimation or avoidance strategies for survival will in turn shape microbial community diversity and biogeochemistry. To assess the extent to which indigenous bacterial and archaeal communities are adapted to changing in redox potential, soils were incubated under static anoxic, static oxic or fluctuating redox potential conditions, and the standing (DNA-based) and active (RNA-based) communities and biogeochemistry were determined. Fluctuating redox potential conditions permitted simultaneous CO2 respiration, methanogenesis, N2O production and iron reduction. Exposure to static anaerobic conditions significantly changed community composition, while 4-day redox potential fluctuations did not. Using RNA : DNA ratios as a measure of activity, 285 taxa were more active under fluctuating than static conditions, compared with three taxa that were more active under static compared with fluctuating conditions. These data suggest an indigenous microbial community adapted to fluctuating redox potential.

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