Pulses of Rapid Ventilation in the North Atlantic Surface Ocean During the Past Century

The Suess Effect is a gradual decrease of the 14 C/ 12 C ratio in tree rings from 1870 to 1950 that is attributed mostly to the burning of 14 C-free fossil fuels for energy. In contrast, pre-nuclear bomb high-precision measurements of 14 C/ 12 C ratios in banded corals from the North Atlantic Ocean do not exhibit the expected Suess Effect. Instead, large biennial-to-decadal shifts in the 14 C/ 12 C ratios appear throughout the coral records. This pattern indicates that rapid pulses of increased mixing between surface and subsurface waters occurred in the North Atlantic Ocean during the past century.