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| Titel |
Impact of changing DOC concentrations on the potential distribution of acid sensitive biota in a boreal stream network |
| VerfasserIn |
H. Laudon, I. Buffam |
| 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 ; 12, no. 2 ; Nr. 12, no. 2 (2008-03-05), S.425-435 |
| Datensatznummer |
250010566
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| Publikation (Nr.) |
 copernicus.org/hess-12-425-2008.pdf |
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| Zusammenfassung |
| DOC concentrations have increased in many surface waters in Europe and North
America over the past few decades. As DOC exudes a strong influence on pH
this DOC increase could have detrimental effects on acid sensitive biota in
many streams and lakes. To investigate the potential implications of changes
in the DOC concentration on stream water biota, we have used a mesoscale
boreal stream network in northern Sweden as a case study. The network was
sampled for stream water chemistry at 60 locations during both winter base
flow and spring flood periods, representing the extremes experienced
annually in these streams both in terms of discharge and acidity. The effect
of changing DOC on pH was modeled for all sampling locations using an
organic acid model, with input DOC concentrations for different scenarios
adjusted by between −30% and +50% from measured present
concentrations. The resulting effect on pH was then used to quantify the
proportion of stream length in the catchment with pH below the acid
thresholds of pH 5.5 and pH 5.0. The results suggest that a change in stream
water DOC during base flow would have only a limited effect on pH and hence
on the stream length with pH below the acid thresholds. During the spring
flood on the other hand a change in DOC would strongly influence pH and the
stream length with pH below the acid thresholds. For example an increase in
DOC concentration of 30% at all sites would increase the proportion of
stream length with pH below 5.5 from 37% to 65%, and the proportion of
stream length with pH below 5.0 would increase from 18% to 27%. The
results suggest that in high DOC waters, even a marginal change in the DOC
concentration could impact acid sensitive biota in a large portion of the
aquatic landscape. |
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