1. Institute for Environmental Studies (IVM), VU University Amsterdam, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands
2. Department of Biology, Norwegian University of Science and Technology (NTNU), Høgskoleringen 5, NO-7491 Trondheim, Norway
3. Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science (NVH), NO-0033 Oslo, Norway
4. Norwegian Polar Institute (NPI), Fram Centre, NO-9296 Tromsø, Norway