Effects of future climate change on primary productivity and export fluxes in the Beaufort Sea

We present projections of future primary production for the Canadian Beaufort Shelf of the Arctic Ocean, using simulations of future climate change from the Canadian Global Climate Model (CGCM2) to force a coupled sea ice-ocean-biological one-dimensional model. We compare three 18 year simulations, 1975-1992, 2042-2059, and 2082-2099, to describe the impacts of a reduction in sea ice cover duration and thickness and an increase in surface freshwater fluxes. Our results show an increase in average annual primary production of 6% between the period 1975-1992 and the period 2042 -2059 and an increase of 9% between 1975-1992 and 2082-2099. The relative contribution of the ice algal and spring phytoplankton blooms to the annual primary production is reduced in the future runs owing to a reduction in the length of the ice algal growth season (resulting from earlier snow and ice melt) and to a reduction in the replenishment of nutrient to the mixed layer in winter. The duration of the summer subsurface phytoplankton bloom increases, which favors the development of the main copepod species and leads to an increase in export production (16% between 1975-1992 and 2082-2099) that is greater than the increase in primary production.