Diversity, abundance, and potential activity of nitrifying and nitrate-reducing microbial assemblages in a subglacial ecosystem

Eric S. Boyd, Rachel K. Lange, Andrew C. Mitchell, Jeff R. Havig, Trinity L. Hamilton, Melissa J. Lafrenière, Everett Shock, John W. Peters, Mark Skidmore

Research output: Contribution to journalArticle

58 Citations (Scopus)

Abstract

Subglacial sediments sampled from beneath Robertson Glacier (RG), Alberta, Canada, were shown to harbor diverse assemblages of potential nitrifiers, nitrate reducers, and diazotrophs, as assessed by amoA, narG, and nifH gene biomarker diversity. Although archaeal amoA genes were detected, they were less abundant and less diverse than bacterial amoA, suggesting that bacteria are the predominant nitrifiers in RG sediments. Maximum nitrification and nitrate reduction rates in microcosms incubated at 47deg;C were 280 and 18.5 nmol of N per g of dry weight sediment per day, respectively, indicating the potential for these processes to occur in situ. Geochemical analyses of subglacial sediment pore waters and bulk subglacial meltwaters revealed low concentrations of inorganic and organic nitrogen compounds. These data, when coupled with a C/N atomic ratio of dissolved organic matter in subglacial pore waters of ~210, indicate that the sediment communities are N limited. This may reflect the combined biological activities of organic N mineralization, nitrification, and nitrate reduction. Despite evidence of N limitation and the detection of nifH, we were unable to detect biological nitrogen fixation activity in subglacial sediments. Collectively, the results presented here suggest a role for nitrification and nitrate reduction in sustaining microbial life in subglacial environments. Considering that ice currently covers 11% of the terrestrial landmass and has covered significantly greater portions of Earth at times in the past, the demonstration of nitrification and nitrate reduction in subglacial environments furthers our understanding of the potential for these environments to contribute to global biogeochemical cycles on glacial-interglacial timescales.

Original languageEnglish (US)
Pages (from-to)4778-4787
Number of pages10
JournalApplied and Environmental Microbiology
Volume77
Issue number14
DOIs
StatePublished - Jul 2011

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Nitrification
Nitrates
Ecosystem
Ice Cover
nitrate reduction
nitrates
nitrate
nitrification
sediments
ecosystems
ecosystem
subglacial environment
sediment
glaciers
Archaeal Genes
porewater
glacier
Nitrogen Compounds
organic nitrogen compounds
Alberta

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Food Science
  • Biotechnology
  • Ecology

Cite this

Boyd, E. S., Lange, R. K., Mitchell, A. C., Havig, J. R., Hamilton, T. L., Lafrenière, M. J., ... Skidmore, M. (2011). Diversity, abundance, and potential activity of nitrifying and nitrate-reducing microbial assemblages in a subglacial ecosystem. Applied and Environmental Microbiology, 77(14), 4778-4787. https://doi.org/10.1128/AEM.00376-11

Diversity, abundance, and potential activity of nitrifying and nitrate-reducing microbial assemblages in a subglacial ecosystem. / Boyd, Eric S.; Lange, Rachel K.; Mitchell, Andrew C.; Havig, Jeff R.; Hamilton, Trinity L.; Lafrenière, Melissa J.; Shock, Everett; Peters, John W.; Skidmore, Mark.

In: Applied and Environmental Microbiology, Vol. 77, No. 14, 07.2011, p. 4778-4787.

Research output: Contribution to journalArticle

Boyd, ES, Lange, RK, Mitchell, AC, Havig, JR, Hamilton, TL, Lafrenière, MJ, Shock, E, Peters, JW & Skidmore, M 2011, 'Diversity, abundance, and potential activity of nitrifying and nitrate-reducing microbial assemblages in a subglacial ecosystem', Applied and Environmental Microbiology, vol. 77, no. 14, pp. 4778-4787. https://doi.org/10.1128/AEM.00376-11
Boyd, Eric S. ; Lange, Rachel K. ; Mitchell, Andrew C. ; Havig, Jeff R. ; Hamilton, Trinity L. ; Lafrenière, Melissa J. ; Shock, Everett ; Peters, John W. ; Skidmore, Mark. / Diversity, abundance, and potential activity of nitrifying and nitrate-reducing microbial assemblages in a subglacial ecosystem. In: Applied and Environmental Microbiology. 2011 ; Vol. 77, No. 14. pp. 4778-4787.
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