Radiocarbon decay and oxygen utilization in the Deep Atlantic Ocean

A parameter based on the sum of the concentrations of PO 4 and O 2 (divided by the Redfield coefficient‐ΔO 2 /δPO 4 ) is used to separate the contributions of the northern and southern components to deep waters in the Atlantic. This separation allows the amount of radiocarbon lost by radiodecay and the amount of oxygen lost to respiration during residence in the deep Atlantic to be calculated. Maps of these quantities reveal strong west to east gradients and weak north to south gradients consistent with ventilation along the western boundary from both ends of the ocean coupled with mixing outward from the boundary. The O 2 and 14 C deficiences are highly correlated, suggesting an O 2 utilization rate of 12 μm/kg per century. The apparent mean isolation time of water in the deep Atlantic is about 200 years.