The western edge of the Gulf Stream has long interested oceanographers because of the dynamic biological and physical nature of its associated frontal region. Not only does the Gulf Stream meander as it flows northeast, but the physical and biological characteristics of the frontal region change within meanders. The dynamics associated with these meanders control the transition between the warmer, more oligotrophic Sargasso Sea water and the colder, seasonally nutrient-rich Slope Water. Rossby et al.  and Levine et al.  used isopycnal floats to track water motion along constant density surfaces and have shown upwelling in anticyclonic/divergent regions of meanders and downwelling in cyclonic/convergent regions.