Contribution of under-ice primary production to an ice-edge upwelling phytoplankton bloom in the Canadian Beaufort Sea

Abstract

The Canadian Beaufort Sea has been categorized as an oligotrophic system with the potential for enhanced production due to a nutrient-rich intermediate layer of Pacific-origin waters. Using under-ice hydrographie data collected near the ice-edge of a shallow Arctic bay, we documented an ice-edge upwelling event that brought nutrient-rich waters to the surface during June 2008. The event resulted in a 3-week long phytoplankton bloom that produced an estimated 31 g C m -2 of new production. This value was approximately twice that of previous estimates for annual production in the region, demonstrating the importance of ice-edge upwelling to the local marine ecosystem. Under-ice primary production estimates of up to 0.31 g C m -2 d -1 showed that this production was not negligible, contributing up to 22% of the daily averaged production of the ice-edge bloom. It is suggested that under-ice blooms are a widespread yet under-documented phenomenon in polar regions, which could increase in importance with the Arctic's thinning ice cover and subsequent increase in transmitted irradiance to the under-ice environment, Copyright 2009 by the American Geophysical Union.