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| Titel |
Are there signs of acidification reversal in freshwaters of the low mountain ranges in Germany? |
| VerfasserIn |
C. Alewell, M. Armbruster, J. Bittersohl, C. D. Evans, H. Meesenburg, K. Moritz, A. Prechtel |
| 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 ; 5, no. 3 ; Nr. 5, no. 3, S.367-378 |
| Datensatznummer |
250002560
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| Publikation (Nr.) |
 copernicus.org/hess-5-367-2001.pdf |
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| Zusammenfassung |
| The reversal of freshwater acidification in
the low mountain ranges of Germany is of public, political and scientific
concern, because these regions are near natural ecosystems
and function as an important drinking water supply. The aim of this study was to
evaluate the status and trends of acidification reversal
after two decades of reduced anthropogenic deposition in selected freshwaters of
the low mountain ranges in the Harz, the Fichtelgebirge,
the Bavarian Forest, the Spessart and the Black Forest. In response to decreased
sulphate deposition, seven out of nine streams
investigated had significantly decreasing sulphate concentrations (all trends
were calculated with the Seasonal Kendall Test). The
decrease in sulphate concentration was only minor, however, due to the release
of previously stored soil sulphur. No increase was found in
pH and acid neutralising capacity (defined by Reuss and Johnson, 1986). Aluminum
concentrations in the streams did not decrease. Thus, no
major acidification reversal can currently be noted in spite of two decades of
decreased acid deposition. Nevertheless, the first signs of improvement
in water quality were detected as there was a decrease in the level and
frequency of extreme values of pH, acid neutralising capacity
and aluminium concentrations in streams. With respect to nitrogen, no change was
determined for either nitrate or ammonium concentrations
in precipitation or stream water. Base cation fluxes indicate increasing net
loss of base cations from all ecosystems investigated, which
could be interpreted as an increase in soil acidification. The latter was due to
a combination of continued high anion leaching and significant
reduction of base cation deposition. No major improvement was noted in
biological recovery, however, initial signs of recovery were
detectable as there was re-occurrence of some single macroinvertebrate species
which were formerly extinct. The results of this study have
important implications for water authorities, forest managers and policy makers:
the delay in acidification reversal suggests a need for ongoing
intensive amelioration of waters, a careful selection of management tools to
guarantee sustainable management of forests and the reduction
of nitrogen deposition to prevent further acidification of soils and waters.
Keywords: freshwater,
acidification reversal, drinking water supply, forested catchments, Germany |
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