Global reorganization of deep-sea circulation and carbon storage after the last ice age
Patrick A. Rafter, William R. Gray, S.K.V. Hines, Andrea Burke, Kassandra M Costa, Julia Gottschalk, Mathis P. Hain, James Rae, John Southon, Maureen H. Walczak, Jimin Yu, Jess F. Adkins, Tim DeVries
Abstract
Using new and published marine fossil radiocarbon ( 14 C/C) measurements, a tracer uniquely sensitive to circulation and air-sea gas exchange, we establish several benchmarks for Atlantic, Southern, and Pacific deep-sea circulation and ventilation since the last ice age. We find the most 14 C-depleted water in glacial Pacific bottom depths, rather than the mid-depths as they are today, which is best explained by a slowdown in glacial deep-sea overturning in addition to a “flipped” glacial Pacific overturning configuration. These observations cannot be produced by changes in air-sea gas exchange alone, and they underscore the major role for changes in the overturning circulation for glacial deep-sea carbon storage in the vast Pacific abyss and the concomitant drawdown of atmospheric CO 2 .