The polar regions are key areas for climate changes and pollution. Many areas can be defined as cold deserts. There is less biodiversity here and food-chains are direct and less complicated. The low temperature causes decomposition to be very low and the enrichment in food chains is high with respect to anthropogenic pollutants in the terrestrial and fresh water ecosystems due to the low productivity. Flora and fauna exist on the edge of what is possible and the effects of the temperature changes will have a profound effect. The Arctic is therefore an ideal place for research in the fields of climate changes and pollution since the observed effects are relatively great and the Arctic can act as an early warning system.

The presence and distribution in soil, catchment areas and lakes of pollutants such as persistent organic compounds, heavy metals and radioactive substances will be studied. Radioactive substances with well-known and defined sources also act as tracers in time and space.

Organic and inorganic pollutants reach the Arctic by long-range atmospheric and oceanic current transport. Volatile compounds, which evaporate to the atmosphere (global distillation) from other warmer terrestrial and marine areas, are deposited by precipitation in the Arctic. The expedition made it possible to study the geographical distribution in east-west and south-north directions covering different atmospheric transport routes and climate regions.

Some elements behave conservatively or are associated with organic colloids and are transported to the sea from the catchment areas. Other elements will be accumulated in lake and river sediments. The lake sediments consequently act as historical archives for the pollution. The rate at which the sediments grow can be determined by observing the peak fallout period in the early 1960s following the nuclear tests at Novaya Zemlya.

To understand modern climate and past climate change in the Canadian Arctic, a detailed and documented paleoclimatic record of the temporal and spatial patterns of natural climate variability over a long time period is crucial. A new technique employing dendroclimatological analysis of the circumpolar shrub, Cassiope tetragona (L.) D. Don (Ericaceae) provides terrestrial climate information at a resolution of yearly increments for up to 150 years. The Tundra Northwest 1999 expedition made possible the collection of C. tetragona plants from 9 of 17 sites visited. The grid of sites will provide high resolution proxy climate data for a large area of the Canadian Arctic from the end of the Little Ice Age up to the present. It will also lead to greater understanding of the temporal and spatial nature of climate variability and temperature increases in the Arctic by elucidating both regional and large-scale patterns.

Fishes such as Arctic char (land-locked and Canadian chars) only live in freshwaters systems, grow slowly and accumulate chlorinated compounds and radioactive caesium. They therefore act as bio-indicators for these elements. In addition they constitute an important food source for the local population and are thus a potential threat to human health.

Theme E includes multi-disciplinary projects, with both aquatic and terrestrial ecology. The objectives include the demonstration of regional differences in pollution load from long-range airborne pollutants to the Arctic, using uniform techniques for sampling and analyses over a large area. A large number of elements and some not formerly investigated organic contaminants will be determined. The projects will use several sample matrices from the terrestrial and aquatic environment; lichens, mosses, lake water, suspended particles in water, bottom sediments, and fish (Arctic char) in order to define the distribution and transport of substances between these compartments of the catchment. The evaluations are supported by a complete analysis of lake water chemistry and a number of physiological and genetic characteristics which will be determined on the collected fishes. The concentration of metals and organic contaminants related to isotope ratios of nitrogen and carbon in the fish tissues will be used in an assessment of the life-history performance of the Arctic char populations.

The sampling strategy and observations of the expedition attempted, as far as possible, to answer questions related to the issues concerning climate changes and pollution of the Arctic tundra. Although local observations are important for the over-all understanding, most of the sample preparations and analysis will have to be carried out in the laboratories at home.