1. a Norwegian Polar Institute , Tromsø , Norway
2. b Norwegian College of Fishery Science , University of Tromsø , Tromsø , Norway
3. c CNRS-INSU, Observatoire Océanologique , Laboratoire d'Océanographie de Villefranche , Villefranche-sur-Mer , France
4. d Alfred Wegener Institute for Polar and Marine Research , Bremerhaven , Germany
5. e University of Stirling , Stirling , Scotland , UK