Distribution of dinoflagellate cysts in the Canadian Arctic marine region

The Canadian Arctic is a major gateway for transport of freshwater from the Arctic Ocean to the North Atlantic. This region comprises the Beaufort Sea , the Canadian Arctic Archipelago (CAA) and northern sections of Baffin and Hudson bays. Subregional differences include major freshwater runoff to th e Beaufort Sea and Hudson Bay, presence of Pacific and Atlantic Intermediat e water in the west, and Atlantic Water in Baffin and Hudson bays. Principa l component analysis of 50 core-top samples shows four subregional dinoflag ellate cyst assemblages. Outer Beaufort Shelf Assemblage I is co-dominated by Operculodinium centrocarpum s.l. and Brigantedinium spp., with minor cys ts of Pentapharsodinium dalei, Algidasphaeridium? minutum s.l. and cysts of Polykrikos spp. Assemblage II in the Canadian Arctic Archipelago is co-dom inated by Brigantedinium sop., A.? minutum s.l. and cysts of Polykrikos spp ., including two Arctic morphotypes. Assemblage III in the North Water poly nya exclusively comprises A.? minutum s.l. and Brigantedinium spp. Assembla ge IV in Baffin Bay is dominated by O. centrocarpum s.l. and Spiniferites s pp., with Brigantedinium spp. on the shelves. The ratio of gonyaulacoid to protoperidinioid cysts (G : P) generally decreases with increased sea-ice c over, but it may also decrease in river plumes and in polynyas. Copyright ( C) 2001 John Wiley & Sons, Ltd.