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| Titel |
Microbial nitrogen cycling on the Greenland Ice Sheet |
| VerfasserIn |
J. Telling, M. Stibal, A. M. Anesio, M. Tranter, I. Nias, J. Cook, C. Bellas, G. Lis, J. L. Wadham, A. Sole, P. Nienow, A. Hodson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 7 ; Nr. 9, no. 7 (2012-07-05), S.2431-2442 |
| Datensatznummer |
250007178
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| Publikation (Nr.) |
 copernicus.org/bg-9-2431-2012.pdf |
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| Zusammenfassung |
| Nitrogen inputs and microbial nitrogen cycling were investigated along a 79 km transect into the Greenland Ice Sheet (GrIS) during the main ablation
season in summer 2010. The depletion of dissolved nitrate and production of
ammonium (relative to icemelt) in cryoconite holes on Leverett Glacier,
within 7.5 km of the ice sheet margin, suggested microbial uptake and
ammonification respectively. Positive in situ acetylene assays indicated
nitrogen fixation both in a debris-rich 100 m marginal zone and up to 5.7 km
upslope on Leverett Glacier (with rates up to 16.3 μmoles
C2H4 m−2 day−1). No positive acetylene assays were
detected > 5.7 km into the ablation zone of the ice sheet. Potential
nitrogen fixation only occurred when concentrations of dissolved and
sediment-bound inorganic nitrogen were undetectable. Estimates of nitrogen
fluxes onto the transect suggest that nitrogen fixation is likely of minor
importance to the overall nitrogen budget of Leverett Glacier and of
negligible importance to the nitrogen budget on the main ice sheet itself.
Nitrogen fixation is however potentially important as a source of nitrogen
to microbial communities in the debris-rich marginal zone close to the
terminus of the glacier, where nitrogen fixation may aid the colonization of
subglacial and moraine-derived debris. |
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