¹⁴C distribution in the Atlantic Ocean

The amount of 14 C produced by nuclear bomb testing that entered the Atlantic Ocean by late 1972 was 1.71×10 −8 μmol/cm 2 of ocean surface area for the west Atlantic (36°S–45°N) and 1.18×10 −8 μmol/cm 2 for the east Atlantic (50°S–28°N) Geochemical Ocean Sections Study stations. There are strong latitudinal differences in the integrated amount of bomb 14 C content in Atlantic waters. Bomb‐produced 14 C is mostly encountered near the center of the large mid‐latitude gyres, whereas the equatorial region has a lower 14 C inventory. The average ocean wide vertical distribution of bomb 14 C in the Atlantic can be explained by a vertical eddy diffusion coefficient of 4.0 cm 2 /s in the surface mixed layer plus thermocline gyre reservoirs. The average 14 C activity per unit area measured in the Atlantic yields an CO 2 exchange rate of 23 mol/m 2 yr, which is equivalent with an atmospheric CO 2 residence time of 6.8 years.