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| Titel |
Riparian zone control on base cation concentration in boreal streams |
| VerfasserIn |
J. L. J. Ledesma, T. Grabs, M. N. Futter, K. H. Bishop, H. Laudon, S. J. Köhler |
| 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 ; 10, no. 6 ; Nr. 10, no. 6 (2013-06-14), S.3849-3868 |
| Datensatznummer |
250018288
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| Publikation (Nr.) |
 copernicus.org/bg-10-3849-2013.pdf |
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| Zusammenfassung |
| Riparian zones (RZ) are a major factor controlling water chemistry in forest
streams. Base cations' (BC) concentrations, fluxes, and cycling in the RZ
merit attention because a changing climate and increased forest harvesting
could have negative consequences, including re-acidification, for boreal
surface waters. We present a two-year study of BC and silica (Si)
flow-weighted concentrations from 13 RZ and 14 streams in different landscape
elements of a boreal catchment in northern Sweden. The spatial variation in
BC and Si dynamics in both RZ and streams was explained by differences in
landscape element type, with highest concentrations in silty sediments and
lowest concentrations in peat-dominated wetland areas. Temporal stability in
BC and Si concentrations in riparian soil water, remarkably stable Mg/Ca
ratios, and homogeneous mineralogy suggest that patterns found in the RZ are
a result of a distinct mineralogical upslope signal in groundwater. Stream
water Mg/Ca ratios indicate that the signal is subsequently maintained in the
streams. Flow-weighted concentrations of Ca, Mg, and Na in headwater streams
were represented by the corresponding concentrations in the RZ, which were
estimated using the Riparian Flow-Concentration Integration Model (RIM)
approach. Stream and RZ flow-weighted concentrations differed for K and Si,
suggesting a stronger biogeochemical influence on these elements, including K
recirculation by vegetation and retention of Si within the RZ. Potential
increases in groundwater levels linked to forest harvesting or changes in
precipitation regimes would tend to reduce BC concentrations from RZ to
streams, potentially leading to episodic acidification. |
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