The Sargasso Sea has been, and continues to be, thefocus for research on new production in the open ocean. The history of theconcept and the evolution of understanding of the mechanisms is reviewed fromits inception in the early 1960s through a controversial period in the 1980sto the current status of a plethora of sources of new nitrogen. Rather thanviewing all processes supplying new nutrients as uniformly distributed overthe Sargasso Sea, it is now clear that new production in the northern or subtropicalarea is primarily sustained by nitrogen injection via mesoscale eddies andwinter convection. In the tropical area, where permanent stratification precludesdeep winter mixing and eddy kinetic energy is low, nitrogen fixation is potentiallythe dominant source along with diapycnal mixing and atmospheric deposition.The timescale of new production measurements has lengthened to an annual basisusing time series measurements and satellite imagery but, in the context ofclimate change, should be lengthened further to greater than decadal scales.