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| Titel |
Recovery from acidification of lakes in Finland, Norway and Sweden 1990–1999 |
| VerfasserIn |
B. L. Skjelkvåle, J. Mannio, A. Wilander, T. Andersen |
| 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.327-338 |
| Datensatznummer |
250002557
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| Publikation (Nr.) |
 copernicus.org/hess-5-327-2001.pdf |
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| Zusammenfassung |
| Sulphate deposition has
decreased by about 60% in the Nordic countries since the early 1980s. Nitrogen
deposition has been roughly constant during the past 20
years, with only a minor decrease in the late 1990s. The resulting changes in
the chemistry of small lakes have been followed by
national monitoring programmes initiated in the 1980s in Finland (163 lakes),
Norway (100 lakes) and Sweden (81 lakes). These lakes are
partly a subset from the survey of 5690 lakes in the Northern European lake
survey of 1995. Trend analyses on data for the period 1990-1999
show that the non-marine sulphate concentrations in lakes have decreased
significantly in 69% of the monitored lakes. Changes were
largest in lakes with the highest mean concentrations. Nitrate concentrations,
on the other hand, were generally low and showed no systematic
changes. Concentrations of non-marine base cations decreased in 26% of the
lakes, most probably an ionic-strength effect due to the
lower concentrations of mobile strong-acid anions. Acid neutralising capacity
increased in 32% of the lakes. Trends in recovery were in part
masked by large year-to-year variations in sea-salt inputs and by increases in
total organic carbon concentrations. These changes were most
probably the result of climatic variations. Nordic lakes, therefore, show clear
signs of recovery from acidification. Recovery began in the
1980s and accelerated in the 1990s. Reductions in sulphur deposition are the
major "driving force" in the process of recovery from acidification.
Further recovery can be expected in the next 10 years if the Gothenburg protocol
on emissions of acidifying pollutants is implemented.
Keywords: Nordic countries, sulphur deposition, lakes, recovery |
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