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| Titel |
Dissolved and particulate reactive nitrogen in the Elbe River/NW Europe: a 2-yr N-isotope study |
| VerfasserIn |
T. Schlarbaum, K. Dähnke, K. Emeis |
| 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 ; 8, no. 12 ; Nr. 8, no. 12 (2011-12-01), S.3519-3530 |
| Datensatznummer |
250006237
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| Publikation (Nr.) |
 copernicus.org/bg-8-3519-2011.pdf |
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| Zusammenfassung |
| Rivers collect and transport reactive nitrogen to coastal seas as nitrate,
ammonium, dissolved organic nitrogen (DON), or particulate nitrogen. DON is
an important component of reactive nitrogen in rivers and is suspected to
contribute to coastal eutrophication, but little is known about seasonality
of DON loads and turnover within rivers. We measured the concentrations and
the isotope ratios 15N/14N of combined DON + NH4+
(δ15DON + NH4+), nitrate (δ15N − NO3−) and
particulate nitrogen (δ15PN) in the non-tidal Elbe River (SE
North Sea, NW Europe) over a period of 2 yr (June 2005 to December 2007)
at monthly resolution. Combined DON + NH4+ concentrations ranged
from 22 to 75 μM and comprised nearly 23% of total dissolved
nitrogen in the Elbe River in annual mean; PN and nitrate concentrations
ranged from 11 to 127 μM, and 33 to 422 μM, respectively. Combined
PN and DON + NH4+ concentrations were, to a first approximation,
inversely correlated to nitrate concentrations. δ15DON + NH4+,
which varied between from 0.8‰ to 11.5‰, changed in parallel
to δ15PN (range 6 to 10‰), and both were
anti-correlated to δ15N − NO3− (range 6 to 23‰).
Seasonal patterns of DON + NH4+ concentrations and
δ15DON + NH4+ diverge from those expected from biological
DON + NH4+ production in the river alone and suggest that the
elution of organic fertilisers significantly affects the DON + NH4+
pool in the Elbe River. |
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