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| Titel |
Distribution of N2O in the Baltic Sea during transition from anoxic to oxic conditions |
| VerfasserIn |
S. Walter, U. Breitenbach, H. W. Bange, G. Nausch, D. W. R. Wallace |
| 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 ; 3, no. 4 ; Nr. 3, no. 4 (2006-11-21), S.557-570 |
| Datensatznummer |
250001165
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| Publikation (Nr.) |
 copernicus.org/bg-3-557-2006.pdf |
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| Zusammenfassung |
In January 2003, a major inflow of cold and oxygen-rich North Sea Water
terminated an ongoing stagnation period in parts of the central Baltic Sea.
In order to investigate the role of North Sea Water inflow in the production
of nitrous oxide (N2O), we measured dissolved and atmospheric N<2O
at 26 stations in the southern and central Baltic Sea in October 2003.
At the time of our cruise, water renewal had proceeded to the eastern
Gotland Basin, whereas the western Gotland Basin was still unaffected by the
inflow. The deep water renewal was detectable in the distributions of
temperature, salinity, and oxygen concentrations as well as in the
distribution of the N2O concentrations: Shallow stations in the Kiel
Bight and Pomeranian Bight were well-ventilated with uniform N2O
concentrations near equilibrium throughout the water column. In contrast,
stations in the deep basins, such as the Bornholm and the Gotland Deep,
showed a clear stratification with deep water affected by North Sea Water.
Inflowing North Sea Water led to changed environmental conditions,
especially enhanced oxygen (O2) or declining hydrogen sulphide
(H2S) concentrations, thus, affecting the conditions for the production
of N2O. Pattern of N2O profiles and correlations with parameters
like oxygen and nitrate differed between the basins. Because of the positive
correlation between ΔN2O and AOU in oxic waters the dominant
production pathway seems to be nitrification rather than denitrification.
Advection of N2O by North Sea Water was found to be of minor
importance. A rough budget revealed a significant surplus of in situ
produced N2O after the inflow. However, due to the permanent halocline,
it can be assumed that the N2O produced does not reach the atmosphere.
Hydrographic aspects therefore are decisive factors determining the final
release of N2O produced to the atmosphere. |
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