Eddy-induced nutrient supply and new production in the Sargasso Sea

A limited area, eddy resolving coupled physical and biological model is used to examine the role of mesoscale dynamical processes in nutrient cycling in the Sargasso Sea. Upwelling due to the formation of cyclonic eddies and their intensification caused by interaction with surrounding mesoscale features causes spatially and temporally intermittent fluxes of nitrate into the euphotic zone. The annual flux resulting from this eddy upwelling process is of the order of 0.5 mol N m−2 year−1, which is sufficient to sustain a rate of new primary production that is consistent with estimates for this region derived from budgets of oxygen and other dissolved gases.