Physical factors controlling summer distribution of chlorophyll a off southwestern Nova Scotia1

Three cruises were taken in summer off southwestern Nova Scotia to elucidate the mechanisms which contribute to the high levels of biological productivity in this area. Biological processes are dominated during summer by the turbulent dissipation of tidal energy which produces a nutrient-rich inshore zone at the surface which gradually becomes stratified in the offshore region. The center of the transitional zone, which separates well mixed from strongly stratified, is marked by a front where chlorophyll concentrations are usually highest. On three occasions over 4 years these regions of high chlorophyll showed considerable spatial similarity, although concentrations varied by a factor of three.