Ventilation of the glacial deep Pacific Ocean

Measurements of the age difference between coexisting benthic and planktic foraminifera from western equatorial Pacific deep-sea cores suggest that during peak glacial time the radiocarbon age of water at 2-kilometers depth was no greater than that of today. These results make unlikely suggestions that a slowdown in deep-ocean ventilation was responsible for a sizable fraction of the increase of the ratio of carbon-14 (C-14) to carbon in the atmosphere and surface ocean during glacial time. Comparison of C-14 ages for coexisting wood and planktic foraminifera from the same site suggests that the atmosphere to surface ocean C-14 to C ratio difference was not substantially different from today's.