WP 8: Environmental evaluation

Targets     Lead Contractor     Lead Partners    

Task 8.1     Task 8.2     Task 8.3     Task 8.4    

Targets

Workpackage 8 is concerned with the external forcings that drive ecological change in the arctic-alpine zone and relates to the Water Framework Directive and to EU, UNECE and national policies on transboundary air pollution. In this workpackage we will use our databases to assess the severity and extent of the impacts of transboundary air pollutants both on mountain lake ecosystems, and, by extension, on mountain ecosystems in general.

Task 8.1.: Sulphur and nitrogen deposition

Mountain lake ecosystems are extremely vulnerable to the effects of acid deposition. Not only are deposition fluxes high and can be enhanced at high altitude but also the relatively thin soils in mountain lake catchments have little ability to retain sulphate and nitrate, and lakes can suffer from severe episodic pollution at the time of spring snow and ice melt. Consequently we will:

1. Use a combination of steady-state, mass balance and catchment models to establish for each mountain region the population of lakes exceeding the critical load, and produce maps of critical loads and critical load exceedance for each mountain Lake District in Europe

2. Use the MAGIC model to test responses to the different S and N emission reduction scenarios proposed by the EU.

3. Use data from representative monitoring stations and sediment records to assess evidence for recovery from acidification.

4. Assess the extent to which the specific inclusion of critical load exceedances from sensitive mountain lakes influences the currently adopted emission abatement targets for EU member states (see WP 9).

Task 8.2.: Toxic trace metals and persistent organic pollutants

In contrast to acidic compounds much less is known about the distribution and fate of these substances in the mountain environment. Consequently we will develop a methodology for assessing critical load exceedance values for metals and POPs in mountain regions and use data from WP 3, WP 5 and WP 6, including our knowledge of the behaviour of radionuclides, to

1. estimate baseline or reference concentrations of trace metals and naturally occurring organic compounds in the water column, sediments and in fish tissue

2. model and map contemporary levels of these pollutants for sites within the Lake Districts across Europe

3. calculate and map the difference between reference and contemporary concentration values as a measure of exceedance

4. use models and on site monitoring at representative sites to derive a relationship between water column, sediment and fish concentrations and the deposition of trace metals and trace organics

5. map critical load exceedances for a range of trace metals and trace organics across Europe

6. validate the results using observations at independent sites

Task 8.3.: Climate change

In addition to the impact of air pollutants, mountain lakes have been significantly influenced over recent decades by rising temperatures and other climate changes. However, it is not clear how much of the climate change at any site is due to greenhouse gas forcing and how much to natural factors such as the North Atlantic Oscillation (NAO). Moreover, because of the inherent natural variability of climate it is difficult to establish simple reference values. On the other hand we have excellent long term meteorological records in Europe and we have robust models for establishing past temperature variations over the last 200 years even in remote mountain regions, while detailed weather patterns can be established from climate re-analysis assimilations for the last 40 years. Consequently we will

1. calculate and map changes in air temperature for alpine regions throughout Europe

2. conduct empirical investigations into the relationship between air temperature, ice cover and surface water temperature based on already available long-term data on air temperature and lake ice cover and the results of the water temperature measurements of WP 1

3. map inter-annual changes in windflow and circulation patterns in Europe since the 1950s

4. assess how daily weather patterns have changed in mountain regions since the 1950s

5. assess the extent to which the observed climate variations in the different regions can be explained by different forcing mechanisms

Task 8.4.: Combining climate change and changes in pollutant loading

Whilst we have good knowledge and promising models for the impact of individual pollutants and climate change on the functioning of remote mountain lakes, we have far less understanding of how lakes respond to combined stresses. Without such understanding it is difficult to generate the process-based models that are needed for scenario testing. Future research projects are needed fully to address this problem, but here we will begin by

1. comparing inter-annual changes in atmospheric pollutant loading with year by year changes in wind patterns and temperature

2. using multivariate statistical analyses to explore the relative importance of geography, climate and pollution in explaining the between site variation in lake biology

3. organising a workshop with relevant national stakeholders to discuss how to use monitoring techniques to identify and explain change, and detect early warning signals

Lead Contractor

1. UIBK-IZL - University of Innsbruck, Institute of Zoology & Limnology, Austria

Lead Partners

• ECRC-UCL - Environmental Change Research Centre, University College London, UK

• UB-DE - Ecology Department, University of Barcelona, Spain

• EAWAG - Department of Environmental Physics, Eidgenoessische Anstalt fur Wasserversorgung, Abwasserreinigung und Gewaesserschutz (EAWAG), Dubendorf, Switzerland