R.: Oceanography of the Canadian Shelf of the Beaufort Sea: A Setting for Marine Life

ABSTRACT. Conservation of marine biodiversity in the Beaufort Sea demands that we understand what individual organisms require of their physical and geochemical environments in order to survive. Specifically, how do the extraordinary spatial and seasonal variations in ice cover, temperature, light, freshwater, turbidity, and currents of the Beaufort Sea define unique places or times critical to marine life? We start with the traditional “bottom-up ” approach, which is to review the strongly seasonal physical forcing of the system, and from it to infer the resultant oceanographic regimes and seasons. This approach, while valuable, remains incomplete: this is due partly to limitations of the data and partly to our limited understanding of this complex system. The oceanographic features (e.g., upwelling regions, recurrent polynyas, coastal currents, sediment types and distributions) define the backdrop that animals “know and understand ” in the sense of interacting with one another and finding food and habitat. We therefore seek clues to the underlying oceanographic processes in the behavioural patterns of fish, marine mammals, and birds. This “top-down ” approach also has limitations, but it offers the opportunity to seek those connections in the system where climate change is likely to have its greatest impact on biological populations. Key words: Beaufort Sea, global warming, upwelling, sea ice, nutrients, sediments RÉSUMÉ. La conservation de la biodiversité marine dans la mer de Beaufort passe par notre compréhension des éléments nécessaires à la survie des organismes individuels au sein de leur environnement physique et géochimique. En particulier, comment les variations spatiales et saisonnières extrêmes dans le couvert glaciel, la température, la lumière, l’eau douce, l