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Titel |
Monitoring strategies of stream phosphorus under contrasting climate-driven flow regimes |
VerfasserIn |
G. Goyenola, M. Meerhoff, F. Teixeira-de Mello, I. González-Bergonzoni, D. Graeber, C. Fosalba, N. Vidal, N. Mazzeo, N. B. Ovesen, E. Jeppesen, Brian Kronvang |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1027-5606
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Digitales Dokument |
URL |
Erschienen |
In: Hydrology and Earth System Sciences ; 19, no. 10 ; Nr. 19, no. 10 (2015-10-08), S.4099-4111 |
Datensatznummer |
250120822
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Publikation (Nr.) |
copernicus.org/hess-19-4099-2015.pdf |
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Zusammenfassung |
Climate and hydrology are relevant control factors determining the timing and amount of nutrient
losses from land to downstream aquatic systems, in particular of phosphorus
(P) from agricultural lands. The main objective of the study was to evaluate
the differences in P export patterns and the performance of alternative
monitoring strategies in streams under contrasting climate-driven flow
regimes. We compared a set of paired streams draining lowland
micro-catchments under temperate climate and stable discharge conditions
(Denmark) and under sub-tropical climate and flashy conditions (Uruguay). We
applied two alternative nutrient sampling programs (high-frequency composite
sampling and low-frequency instantaneous-grab sampling) and estimated the
contribution derived from point and diffuse sources fitting a source
apportionment model. We expected to detect a pattern of higher total and
particulate phosphorus export from diffuse sources in streams in Uruguay
streams, mostly as a consequence of higher variability in flow regime (higher
flashiness). Contrarily, we found a higher contribution of dissolved P in
flashy streams. We did not find a notably poorer performance of the
low-frequency sampling program to estimate P exports in flashy streams
compared to the less variable streams. We also found signs of interaction
between climate/hydrology and land use intensity, in particular in the
presence of point sources of P, leading to a bias towards underestimation of
P in hydrologically stable streams and overestimation of P in flashy streams.
Based on our findings, we suggest that the evaluation and use of more
accurate monitoring methods, such as automatized flow-proportional water
samplers and automatized bankside analyzers, should be prioritized whenever
logistically possible. However, it seems particularly relevant in currently
flashy systems and also in systems where climate change predictions suggest
an increase in stream flashiness. |
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