Ecological Consequences of Upwelling in the Southeast Beaufort Sea

Assessing the current and future primary productivity of the Arctic Ocean in the context of rapid climate change is a challenging task. The main issues are to (1) adequately estimate primary production in a dynamic-ice environment, (2) tease apart the effects of directional change and climate oscillations against a backdrop of high inter-annual variability, (3) assess the relative importance of light and nutrients in controlling primary production in the upper mixed layer (visible to orbiting sensors) and underneath in subsurface chlorophyll maxima, and (4) evaluate the impact of these limitations on the success of different functional groups of primary producers. A hierarchy of factors is proposed, whereby order-of-magnitude differences in primary productivity at the pan-arctic scale are controlled by the dominant stratification regime and the nature of periodic nutrient subsidies, whereas smaller changes within a region are due to synergistic interactions between light and episodic nutrient inputs into the upper euphotic zone. Potentially important episodic sources of nutrients in the strongly stratified sectors of the Arctic include eddies and different types of upwelling. The far-reaching implications of upwelling on the coastal ecosystem of the southeast Beaufort Sea are addressed using recent data from the fourth International Polar Year.