We reconstructed the radiocarbon activity of intermediate waters in the eastern North Pacific over the past 38,000 years. Radiocarbon activity paralleled that of the atmosphere, except during deglaciation, when intermediate-water values fell by more than 300 per mil. Such a large decrease requires a deglacial injection of very old waters from a deep-ocean carbon reservoir that was previously well isolated from the atmosphere. The timing of intermediate-water radiocarbon depletion closely matches that of atmospheric carbon dioxide rise and effectively traces the redistribution of carbon from the deep ocean to the atmosphere during deglaciation.
Marchitto, Thomas M; Lehman, Scott J; Ortiz, Joseph; Fluckiger, Jacqueline; van Geen, Alexander (2007). Marine Radiocarbon Evidence for the Mechanism of Deglacial Atmospheric CO2 Rise. Science 316(5830) 1456-1459. doi: 10.1126/science.1138679. Retrieved from https://oaks.kent.edu/geolpubs/43