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| Titel |
Technical Note: A comparison of two empirical approaches to estimate in-stream net nutrient uptake |
| VerfasserIn |
D. von Schiller, S. Bernal, E. Martí |
| 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. 4 ; Nr. 8, no. 4 (2011-04-08), S.875-882 |
| Datensatznummer |
250005689
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| Publikation (Nr.) |
 copernicus.org/bg-8-875-2011.pdf |
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| Zusammenfassung |
| To establish the relevance of in-stream processes on nutrient export at
catchment scale it is important to accurately estimate whole-reach net
nutrient uptake rates that consider both uptake and release processes. Two
empirical approaches have been used in the literature to estimate these
rates: (a) the mass balance approach, which considers changes in ambient
nutrient loads corrected by groundwater inputs between two stream locations
separated by a certain distance, and (b) the spiralling approach, which is
based on the patterns of longitudinal variation in ambient nutrient
concentrations along a reach following the nutrient spiralling concept. In
this study, we compared the estimates of in-stream net nutrient uptake rates
of nitrate (NO3) and ammonium (NH4) and the associated uncertainty
obtained with these two approaches at different ambient conditions using a
data set of monthly samplings in two contrasting stream reaches during two
hydrological years. Overall, the rates calculated with the mass balance
approach tended to be higher than those calculated with the spiralling
approach only at high ambient nitrogen (N) concentrations. Uncertainty associated with
these estimates also differed between both approaches, especially for
NH4 due to the general lack of significant longitudinal patterns in
concentration. The advantages and disadvantages of each of the approaches
are discussed. |
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