The Zackenberg station in the evening and northern lights in autumn. Since 2007 the station has extended its season from June, July and August to March/April to October. The sun goes below the horizon on 6-7 November and does not reappear before February 4. (Photo: Lars Holst Hansen © Aarhus University)

Ten modest buildings with laboratories, offices, storage rooms, a canteen and all other facilities that you may need make up Zackenberg research station, far up in North-East Greenland.

These days, the station celebrates its 20th anniversary and we seize the opportunity to look back at some of the discoveries made at the remote station, operated by the Department of Bioscience at Aarhus University.

Every summer the station attracts scientists from all around the world, studying, among other topics, climate change, Arctic biology and ecosystem interactions.

One of the advantages of studying climate change and ecosystems in extreme environments is that many of the changes taking place with a warming climate are particularly evident up there. Therefore, research into Arctic environments may enable the scientists to discover a number of mechanisms that the rest of the world will experience in the future when the climate changes take effect.

Over the years, the scientists have discovered that:

Temperature decides which animals are included in the food chain
Previously, focus has been directed at the ability of the individual species to survive in an ever warmer Arctic; however, a study from 2014 has shown that climate change affects the entire food chain. Along with studies of food chains in the African Savannah, the scientists are approaching a revelation of the principle of how food chains are composed and how they work.

Key species are of great importance for the entire ecosystem
A collapse of the population of northern collared lemming in Greenland has had surprisingly great importance for the predators that have it on their menu. It may eventually lead to the complete disappearance of species such as snowy owl, ermine and small skua from the Arctic.

Warmer weather may fundamentally change the conditions of life in the Arctic
As temperatures rise in the Arctic, the area's plant communities change dramatically, with major consequences for ecosystems. In the low Arctic region, the temperature increases are already observable in that dwarf shrubs spread and become higher. The same phenomenon is also expected to occur in the high Arctic.

Flowers and their pollinators becoming out of sync
The responses by Arctic flowers to increased temperatures are quite different from the insects that pollinate them. The more differently they develop, the greater the risk that both will disappear completely.

Arctic lakes are full of life – even in winter
Although the Arctic lakes may be covered by several metres of ice and snow for 8-9 months a year, they still contain plenty of life. Studies have even shown that some species perform better in the deep dark lakes when winter is at its hardest. These include copepods, which in winter can wave goodbye to most of their enemies that have gone dormant. Therefore, they may use winter to grow large and become mature.

The richness of life in the ocean is directly related to the amount of sea ice
In just over 60 years, the ice-free period at Young Sound fjord near Zackenberg has increased by 14 days. The fewer ice-free days per year reduce the growth of algae, which again inhibits the growth of mussels and sea urchins, and a study thus concludes that changes in sea ice will have a direct impact on plant and animal life in the Arctic ocean.

Surprisingly large amounts of methane released when autumn sets in
It is not only in summer that considerable amounts of the greenhouse gas methane are released into the atmosphere, when autumn sets in and the tundra freezes the release is just as high or in some cases even higher. This knowledge can help increase our understanding of seasonal variations for the emission of greenhouse gases.

Grazing musk oxen enhance global warming
Arctic wetlands are major producers of the highly potent greenhouse gas methane. When the large musk oxen graze, plant biomass is removed, and this impacts the uptake and release of CO₂. At the same time, grazing affects the composition of plant species in the areas and may result in increased emissions of methane.

The content of water in the permafrost has a direct impact on greenhouse gas emissions
Permafrost thaws, thus contributing to the release of carbon dioxide and other greenhouse gases into the atmosphere. However, a study has shown that emissions of carbon dioxide and other greenhouse gases relate directly to the content of water in the soil. If the permafrost is saturated by water after thawing, greenhouse gases will be released significantly slower than usual. This knowledge is now included directly in climate models.

Canadian Noémie Boulanger-Lapointe worked as a field biologist for The Biobasis programme in 2011. Here, she is about to bring back marker sticks used to systematically search an area for winter nests left by the northern collared lemming, now visible in summer. The number of winter nests is used as an indirect measure of the number of northern collared lemming, an important prey for small skua, polar fox and ermines. Their number may have indirect consequences for alternative items of prey such as eggs and young of wading birds. (Photo: Lars Holst Hansen © Aarhus University)