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| Titel |
Biogenic nitrogen gas production at the oxic–anoxic interface in the Cariaco Basin, Venezuela |
| VerfasserIn |
E. Montes, M. A. Altabet, F. E. Muller-Karger, M. I. Scranton, R. C. Thunell, C. Benitez-Nelson, L. Lorenzoni, Y. M. Astor |
| 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 ; 10, no. 1 ; Nr. 10, no. 1 (2013-01-17), S.267-279 |
| Datensatznummer |
250017471
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| Publikation (Nr.) |
 copernicus.org/bg-10-267-2013.pdf |
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| Zusammenfassung |
| Excess nitrogen gas (N2xs) was measured in samples collected at
six locations in the eastern and western sub-basins of the Cariaco Basin,
Venezuela, in September 2008 (non-upwelling conditions) and March 2009
(upwelling conditions). During both sampling periods, N2xs
concentrations were below detection in surface waters, increasing to
~ 22 μmol N kg−1 at the oxic–anoxic interface
([O2] < ~ 4 μmol kg−1, ~ 250 m). Below
the oxic–anoxic interface (300–400 m), the average concentration of
N2xs was 24.7 ± 1.9 μmol N kg−1 in
September 2008 and 27.5 ± 2.0 μmol N kg−1 in March
2009, i.e., N2xs concentrations within this depth interval were
~ 3 μmol N kg−1 higher (p < 0.001) during the
upwelling season compared to the non-upwelling period. These results suggest
that N-loss in the Cariaco Basin may vary seasonally in response to changes
in the flux of sinking particulate organic matter. We attribute the increase
in N2xs concentrations, or N-loss, observed during upwelling to:
(1) higher availability of fixed nitrogen derived from suspended and sinking
particles at the oxic–anoxic interface and/or (2) enhanced ventilation at the
oxic–anoxic interface during upwelling. |
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