Druffel,-E.R.M.  Decade time scale variability of ventilation 
	in the North Atlantic: High-precision measurements of `
	bomb radiocarbon in banded corals.  J.-GEOPHYS.-RES.-C-
	OCEANS. 1989. vol. 94, no. C3, pp. 3271-3285.

High-precision radiocarbon data for the upper ocean are 
presented for banded corals from 2 North Atlantic sites. 
Dissimilarities between post-1950 records at Bermuda 
(Sargasso Sea) and the Florida Straits (Gulf Stream) show the 
different mixing processes. Convective overturn associated 
with 18 degree  water formation during late winter in the 
northern Sargasso facilitates storage of considerable 
quantities of bomb radiocarbon at depth, which accounts for 
the damping of the  Delta  super(14)C signal at Bermuda 
during the 1960's. A multibox isopycnal mixing model 
estimates the ventilation rate of the upper 700 m of the 
water column in the Sargasso from 1950-83. An inverse model 
is used; i.e. water mass renewal rate was calculated for the 
post-bomb period to satisfy the bomb radiocarbon time history 
in the corals. Sea water radiocarbon data from GEOSECS (1972-
1973) and Transient Tracers in the Ocean (1980-1981) surveys 
are used to constrain the subsurface radiocarbon values 
calculated by the model. Water mass renewal in the Sargasso 
was high during 1963-64, fell in the late 1960s, remaining 
low during the 1970s. The  super(14)C-derived record of water 
mass renewal precedes by about 4 yr that derived from 
isopycnal salinity in the Sargasso, illustrating that coral  
super(14)C record is controlled to a large extent by ocean 
circulation rather than atmospheric exchange of CO sub(2).