316 



THE DEEP SEA 



1.00 



ATM 



=#fc 



HMr4 



if 



P. + I.S.W. 



.96 



.77 



P.+ I.D.W. 



A 



N 



T 



A 



R, R 



I «i 



?^S.AS.W. 



96 



f N AS.W. 



.90 



A.D.W. 



Fig. 8. Box model of large-scale oceanic mixing. Arrows indicate allowed modes 

 )f transfer between reservoirs. Numbers refer to relative C^/C^'^ ratios. 



for four of the reservoirs. The value for the deep Pacific is 0.77 of 

 the atmospheric value or —230 on the per mil scale, for the deep 

 Atlantic, 0.90 or — 100 on the per mil scale, for both the surface 

 Pacific and the surface North Atlantic 0.96 or —40 on the per mil 

 scale. This uniquely determines the four unknown rates, Rx, Ro, 

 Rs, and L, and the three undetermined concentrations, the C^^ 

 concentrations in the Arctic, Antarctic, and South Atlantic 

 surface water (SAS\\'), are fixed mathematically. These results 

 are shown in Table IX. The concentrations fixed by the model 

 for the Antarctic, Arctic, and South Atlantic surface water agree 

 satisfactorily with available measurements. The COo exchange 

 rate between atmosphere and ocean agrees well with that of Craig 

 based on a simpler but somewhat similar model. The rate of net 

 northward transport in the Atlantic is consistent with the em- 

 pirical estimate of 430 X 10^'- moles C/year computed from 

 Sverdrup et aL, The Oceans. 



