Long-term changes in acidification and recovery at nine calibrated catchments in Norway, Sweden and Finland

Abstract

International agreements to reduce the emissions of acidifying pollutants have resulted in major changes in deposition of sulphur and nitrogen in southern Scandinavia over the past 25 years. Long-term monitoring of deposition and run-off chemistry over the past 12-25 years at nine small calibrated catchments in Finland, Norway and Sweden provide the basis for analysis of trends with special attention to recovery in response to decreased sulphur and nitrogen deposition in the 1980s and 1990s. During the 1980s and 1990s sulphate deposition in the region decreased by 30 to 60%, whereas inorganic nitrogen deposition showed very little change until the mid-1990s. Deposition of non-marine base cations (especially calcium) declined in the 1990s most markedly in southern Finland. Run-off response to these changes in deposition has been rapid and clear at the nine catchments. Sulphate and base cations (mostly calcium) concentrations declined and acid neutralising capacity increased. Occasional years with unusually high inputs of sea-salt confound the general trends. Trends at all the catchments show the same general picture as that from small lakes in Scandinavia and in acid-sensitive waters elsewhere in Europe.

Keywords

acidification; recovery; Scandinavia; catchment; trend analysis

Published in

Hydrology and Earth System Sciences
2001, volume: 5, number: 3, pages: 339-349

SLU Authors

• Löfgren, Stefan

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

Associated SLU-program

Lakes and watercourses
Forest
Acidification
Use of FOMA data

UKÄ Subject classification

Oceanography, Hydrology, Water Resources
Environmental Sciences
Geochemistry

Publication identifier

• DOI: https://doi.org/10.5194/hess-5-339-2001

Permanent link to this page (URI)

https://res.slu.se/id/publ/39217