The Mackenzie Shelf-budgets and problems
Robie W. Macdonald
Institute of Ocean Sciences 9860 West Saanich Road
P.O. Box 6000, Sidney, B.C.Canada,V8L 4B2
Tel: 1-250-363-6409
Fax: 1-250-363-6807
MacDonaldRob@dfo-mpo.gc.ca
K.C. Ruttenberg, C. Gobeil
The Mackenzie Shelf is unique for the North American side of the Arctic Ocean in that it comprises a wide shelf dominated by input from a large, sediment rich river. Here, we examine budgets for fresh water, sediments, organic carbon and nutrients. The Mackenzie River clearly dominates the region, but the formation of ice is also crucial in controlling how the shelf interfaces land and ocean. The shelf can by no means be considered a passive receptor of terrestrial and marine inputs; it reprocesses those inputs exporting some and sequestering others. Although present data allow one to contrain quite well the input of materials from land, our understanding of partitioning between delta and shelf and the exchange at the shelf edge is not sufficient to provide an accurate budget for some components. The greatest leverage for climate change in the Arctic Ocean is arguably on the shelves yet we do not know enough to predict even the direction of that change insofar as impact on biogeochemical cycling.
