1. a Institute of Geography, University of Copenhagen , Øster Voldgade 10, DK-1350 , Copenhagen K. , Denmark
2. b Department of Geography , University of Guelph , Guelph , Ontario , N1G 2W1 , Canada
3. c Scarbrough College Coastal Research Group , University of Toronto at Scarborough , Scarborough , Ontario , M1C 1A4 , Canada