Mesoscale Distribution of Springtime Waters and Nutrients near the Continental Shelf Break, Beaufort Sea, Alaska

ABSTRACT

Forty two sites on the Alaskan Beaufort Sea shelf break were sampled by helicopter in April 2003 for hydrographic parameters and nutrients. Mesoscale maps delineated two eddies and the Beaufort shelf break current. Higher-salinity nutrient-rich waters upwelled onto the shelf, and the depth of the main pycnocline shoaled to <22 m. A plume of 31.40-31.80 salinity water at 10 m was flowing off the shelf, and maps of Brunt Vaisala frequencies and Richardson numbers showed that its presence weakened the pycnocline stability. The high shelf-break nutrient concentrations could support a spring-bloom productivity of 23 g-C m^-2 y^-1, which, when added to previous summertime productivity measurements, demonstrated significant production along the Beaufort Sea shelf break.