1. WGE 27.-29. September 20111Brit Lisa Skjelkvåle Trends in precipitation chemistry, surface water chemistry and aquatic biota in acidified areas in Europe and North America from 1990 to 2008 ICP Waters Programme Centre Norwegian Institute for Water Research

2. WGE 27.-29. September 20112Brit Lisa Skjelkvåle Aim of the report Describe the changes in acid sensitive aquatic ecosystems in Europe and North America due to emission reductions

3. WGE 27.-29. September 20113Brit Lisa Skjelkvåle The last 50 years 60s – 70s: increase in deposition - severe acidification – fish deaths – forest dieback – concerns leading to establishment of the LRTAP Convention 80s : decrease in deposition - small (no) changes in water chemistry and no changes in biota 90s : large decrease in deposition - large changes in water chemistry and small positive changes (recovery) in biota 00s : ?? – Does the positive development in water chemistry continue? and at what rate? – What is the rate of change in the biological recovery?

4. WGE 27.-29. September 20114Brit Lisa Skjelkvåle Chain of effects Emission reductions of S and N  changes in precipitation chemistry  changes in water chemistry  possible effects on aquatic biota (recovery)

5. WGE 27.-29. September 20115Brit Lisa Skjelkvåle Responsible for the different parts of the report Emissions: From EMEP reports Precipitation: EMEP CCC contribution Water chemistry: ICP Waters database and all Task Force members Biology: National contributions from 6 countries

6. WGE 27.-29. September 20116Brit Lisa Skjelkvåle Time spans in the report 1990 – 1999 = 90s 1999 – 2008 = 00s and the whole period together 1990 - 2008

7. WGE 27.-29. September 20117Brit Lisa Skjelkvåle Emissions reductions Changes in concentrations in precipitation S

8. WGE 27.-29. September 20118Brit Lisa Skjelkvåle Emissions reductions NO x Changes in concentrations in precipitation

9. WGE 27.-29. September 20119Brit Lisa Skjelkvåle EMEP CCC monitoring network used for the analysis

10. WGE 27.-29. September 201110Brit Lisa Skjelkvåle ICP Waters network Chemistry at all sites Biology at selected sites and not in all countries

11. WGE 27.-29. September 201111Brit Lisa Skjelkvåle Changes in sulphate* concentrations in surface waters ÷ ÷ ÷ ÷ ÷ ÷ ÷ ÷ + + + ÷

12. WGE 27.-29. September 201112Brit Lisa Skjelkvåle Trends in ANC 1990-1999 and 1999-2008 ICP Waters sites All median trend slopes in all regions are positiv Slightly lower increase 1999-2008 than 1990-1999

13. WGE 27.-29. September 201113Brit Lisa Skjelkvåle Main conclusions of changes in water chemistry Sulphate: About 70 % of nearly 200 sites, and 11 of 12 regions show significant declines in non-marine sulphate in the 90s and the 00s. Decrease has slowed down in the 00 compared to the 90s Nitrogen: Most sites show no significant trends in nitrate The relative importance of NO3 for acidification of surface waters has increased The changes in N is the same for the 90s and the 00s

14. WGE 27.-29. September 201114Brit Lisa Skjelkvåle Main conclusions of changes in water chemistry Alkalinity/ANC: Increase has slowed down in most regions pH: Most European regions show more improvements in the 00s while in North America the changes it is much of the same Organic carbon: No evident differences between the two periods – still increase

15. WGE 27.-29. September 201115Brit Lisa Skjelkvåle Biological recovery

16. WGE 27.-29. September 201116Brit Lisa Skjelkvåle Conclusions Improvements in acidification of surface waters are related to lower acid deposition The reductions of acidifying components in precipitation are larger and quicker than the observed improvements in water chemistry Increase in pH, alkalinity and ANC indicate that biological recovery can be expected Biological recovery is documented in many regions in Europe – Full recovery is not documented anywhere. – A return to pre-industrial biodiversity is unlikely Several areas in Europe will never achieve good (non-acidified) water quality with current legislation of emissions of acidifying components. Future reductions of both S and N deposition would be necessary to achieve biological recovery not influenced by acidification.

17. WGE 27.-29. September 201117Brit Lisa Skjelkvåle The last 50 years 60s – 70s: increase in deposition - severe acidification – fish deaths – forest dieback – concerns leading to establishment of the LRTAP Convention 80s : decrease in deposition - small (no) changes in water chemistry and no changes in biota 90s : large decrease in deposition - large changes in water chemistry and small positive changes (recovery) in biota 00s : less decrease in deposition - chemical recovery is slowing down, more signs of biological recovery, but ecosystems are still fragile

18. WGE 27.-29. September 201118Brit Lisa Skjelkvåle www.icp-waters.no www.icp-waters.no the report will be avilable in October