1. Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
2. Arctic Research Centre, Aarhus University, Ny Munkegade 116, 8000 Aarhus C, Denmark
3. Natural Resource Sciences, McGill University, Ste Anne de Bellevue, Quebec Canada, H9X 3V9
4. Greenland Institute of Natural Resources, 3900 Nuuk, Greenland
5. Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK, USA
6. Cooperative Institute for Research in the Atmosphere, Colorado State University, Fort Collins, CO, USA