3D Cape Hatteras/ Sargasso Sea 



Charles S. Yentsch 



Bigeiow Laboratory of Ocean Sciences 

 West Boothbay Harbor, Maine 



The density fields of large ocean currents such as the Gulf Stream are 

 baroclinic analogues of upwelling and represent the largest and perhaps 

 most important mechanism in the world's ocean for the vertical transport 

 of nutrients. The conceptual model (49-1) illustrates this mechanism. 

 When the earth's rotation (Ci) is considered as balancing the pressure 

 gradient (Pg), there is a secondary cross-stream flow— that is an 

 aegeostrophic flow— associated with the horizontal advection of the 

 current. This cross-stream flow is transported along lines of equal density 

 from the Sargasso Sea into the slope waters off New England. This flow 

 transports nutrients such as nitrogen and is the reason the slope waters are 

 more heavily populated with phytoplankton than the Gulf Stream proper. 



Cf 



49-1. Conceptual Model of Vertical Transport of Nutrients. 



49 



