1. Department of Environmental BiologyUniversity of Guelph Bovey Building, Guelph, Ontario N1G 2W1 Canada
2. National Water Research Institute Environment Canada 867 Lakeshore Road, Burlington, Ontario L7R 4A6 Canada
3. Department of ChemistryUniversity of Toronto 80 St. George Street, Toronto, Ontario M5S 3H6 Canada
4. National Environmental Research Institute of Denmark P.O. Box 358, Frederiksborgvej 399, DK‐4000, Roskilde Denmark
5. Greenland Institute of Natural Resources P.O. Box 570, DK‐3900 Nuuk, Greenland Denmark
6. National Wildlife Research CentreCarleton University 1125 Colonel By Drive, Raven Road, Ottawa, Ontario K1A 0H3 Canada