The arctic and alpine regions of Europe represent the most remote and least disturbed environments in Europe, yet they are threatened by acid deposition, toxic air pollutants and by climate change. The remote lakes that occur throughout these regions are especially sensitive to these threats for a number of related reasons:

- many have little ability to neutralise acidity because of their low base status;

- nitrate levels are higher because their catchments have little soil and vegetation to take up nitrogen deposition;

- toxic trace metals and trace organics accumulate in the food chain more easily, and some pollutants (e.g. mercury, volatile organics) accumulate preferentially in cold regions;

- climatic warming in Europe is predicted to be greatest in arctic and alpine regions.

Because of this sensitivity remote mountain lakes are not only vulnerable to environmental change they are also excellent sensors of change, and their high quality sediment records can be used to infer the speed, direction and biological impact of changing air quality and climate.

The MOLAR project builds on the success of the EU funded projects AL:PE.1 (Acidification of Remote Mountain Lakes: Palaeolimnology and Ecology) and AL:PE.2 (Remote Mountain Lakes as Indicators of Air Pollution and Climate Change), which represented the first comprehensive study of remote mountain lakes at a European level. A major report of the first phase of this project has been recently published (Wathne et al. 1995) and the conclusions of the second phase have been presented and published at two conferences in Gothenburg and Copenhagen respectively (Wathne et al. in prep., Battarbee et al. in prep.)

The AL:PE project assessed the status of remote mountain lakes throughout Europe on the basis of sediment core records and chemical and biological surveys. The MOLAR project focuses on detailed studies of a smaller number of key sites to provide high resolution data on their temporal dynamics that can then be used to develop and calibrate predictive models.

The project has four overall objectives, each corresponding to a major strand in the proposal:

- to measure and model the dynamic responses of remote mountain lake ecosystems to acid (sulphur plus nitrogen) deposition;

- to quantify and model pollutant (trace metals, trace organics) fluxes and pathways in remote mountain lakes and their uptake by fish;

- to measure and model the temporal responses of remote mountain lake ecosystems to climate variability on seasonal, inter-annual and decadal time-scales.

- to continue the development of a high quality environmental database on remote mountain lake ecosystems in Europe and to disseminate results widely to enhance public awareness, environmental education and environmental decision making.

The main deliverable generated by this project will be the development of predictive models for acidity, pollutant flux and climate variability that can be used in scenario assessment studies, especially those scenarios associated with present and forthcoming UNECE protocols and General Circulation Model (GCM) predictions for Europe. A desirable future objective would be the linking of these models to evaluate the interaction between acidity, trace pollutants and climate. However, this must inevitably wait until a further phase of research.

In addition to model development, much of the field and laboratory work proposed is innovative for studies of such remote sites, especially:

- the focus on the seasonal dynamics of the lake systems;

- the emphasis on nitrogen deposition and its biological impact;

- the study of microbial food webs in relation to acidity;

- the on-site collection and measurement of atmospheric pollutants;

- the use of radio-tracers to validate pollutant transport models;

- the study of trace metal (especially mercury) and trace organic uptake by fish;

- the on-site monitoring of climatic conditions and their relationship to water column behaviour;

- the development of a methodology to infer climate trends from the high resolution analysis of recent sediments.

These objectives were unachievable four years ago because of the almost complete lack of information on remote arctic and alpine lakes. It is now possible to carry out such work because of the knowledge gained about individual sites from the AL:PE project with respect particularly to accessibility, morphometry, chemistry, biology, sediment accumulation rate and pollution status.