GULF-STREAM FRONTAL EDDY INFLUENCE ON PRODUCTIVITY OF THE SOUTHEAST UNITED-STATES CONTINENTAL-SHELF

Weekly period meanders and eddies are persistent features of Gulf Stream frontal dynamics from Miami, Florida, to Cape Hatteras, North Carolina. Satellite imagery and moored current and temperature records reveal a spatial pattern of preferred regions for growth and decay of frontal disturbances. Growth regions occur off Miami, Cape Canaveral, and Cape Fear due to baroclinic instability, and decay occurs in the confines of the Straits of Florida between Miami and Palm Beach, between 30-degrees and 32-degrees-N where the stream approaches the topographic feature known as the Charleston bump and between 33-degrees-N and Cape Hatteras. Eddy decay regions are associated with elongation of frontal features, offshore transport of momentum and heat, and onshore transport of nutrients. Onshore transport of new nitrogen from the nutrient-bearing strata beneath the Gulf Stream indicates that frontal eddies serve as a "nutrient pump" for the shelf. New nitrogen flux to the shelf due to Gulf Stream input could support new production of 7.4 x 10(12) g C yr-1 or about 8 million tons carbon per year if all nitrate were utilized. Calculations indicate that approximately 70% of this potential new production is realized, yielding an annual new production for the outer shelf of 4.3 x 10(12) g C.