Comparison of Oceanic Δ14C Data with Those of GEOSECS: Vertical Profiles in 1973 (GEOSECS) and in 1980 at (30° N, 170° E) in the Northwestern Pacific Ocean

Abstract

The vertical profile of radiocarbon at (30° N, 170° E) measured in 1980 was compared with the GEOSECS data measured in 1973. ¹⁴C was extracted from 200L of sea water, converted to C₂H₂, and analyzed with a gas proportional counter. Our profile and that of GEOSECS were in good agreement below 700m depth without systematic deviation of Δ¹⁴C values between both measurements. On the other hand, a Δ¹⁴C increase was observed above 700m depth, reflecting the transient addition, in 6.6 years, of bomb ¹⁴C to the intermediate layer from the atmosphere.