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| Titel |
Dual nitrate isotopes in the Dutch and German Wadden Sea and its tributary rivers |
| VerfasserIn |
Tina Sanders, Philipp Wiese, Kirstin Dähnke |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250123430
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| Publikation (Nr.) |
 EGU/EGU2016-2680.pdf |
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| Zusammenfassung |
| The Dutch and German Wadden Sea is threatened by the river-induced eutrophication due to
riverine nitrate. Despite reduction of nutrient inputs to rivers in the past decades, nitrate
inputs remain problematic, also because the estuary of one of the main contributing rivers, the
Elbe River, has now developed from a net nitrate sink to a nitrate source.
During a sampling campaign in August 2014 we measured nitrate concentration and dual
isotope signatures in the Wadden Sea and in two contributing rivers, the Ems and the Elbe
River. Our goal was to assess individual riverine contributions and turnover mechanisms of
nitrate in the estuaries and the Wadden Sea itself using dual nitrate isotopes as fingerprint
signatures.
Nitrate concentration in the Ems River and Estuary twice exceeded that of the Elbe River.
δ15N and δ18O of nitrate nevertheless showed that denitrification was active in the Ems
estuary, removing nitrate, whereas nitrification produced new nitrate in the Elbe Estuary.
Surprisingly, Wadden Sea samples appeared not to be entirely dominated by these two
riverine source signatures. This suggests that additional turnover mechanisms in
the Wadden Sea itself or inputs of nitrate from the open North Sea additionally
affect the isotope composition of nitrate in the Dutch and German Wadden Sea. |
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