The distribution of radiocarbon in the glacial ocean

Abstract

Accelerator mass spectrometric radiocarbon measurements on benthic foraminifera shells, picked from samples on which concordant ages were obtained on the shells of two species of planktonic foraminifera, reveal that the age of deep water in the equatorial Atlantic during glacial time was 675±80 years (compared to today's age of 350 years) and that the age of deep water in the South China Sea was 1670±105 years (compared to today's value of 1600 years). These results demonstrate that the 1.3 to 1.5 times higher radiocarbon content of carbon in glacial surface waters of the Caribbean Sea reconstructed by Bard et al. [1990] was primarily the result of a higher global inventory of radiocarbon rather than a decrease in rate of mixing between surface and deep waters of the ocean. The results are also consistent with the conclusion by Boyle and Keigwin [1987] that the flow of North Atlantic Deep Water was considerably weakened during glacial time, allowing deep waters of Antarctic origin to push much further north into the Atlantic than they do today.

The influence of the ocean circulation state on ocean carbon storage and CO<sub>2</sub> drawdown potential in an Earth system model

“…Broecker et al, 1990;Sikes et al, 2000;Keigwin and Schlegel, 2002;Skinner et al, 2010Skinner et al, , 2015, it seems possible that the effect of increased mixing was indeed offset by some other process. One such factor could be that the global ocean was saltier and more stratified (Ballarotta et al, 2014).…”

Absolute Production of Radiocarbon and the Long-Term Trend of Atmospheric Radiocarbon

“…The increase of the rate of decline, caused by the E-I mechanism, is similar for all the scenarios of 14 C production. (Broecker et al 1990). The fluxes introduced to balance the decay and production of radiocarbon are displayed with thick arrows.…”

Comparison of water mass changes in the deep tropical Atlantic derived from Cd/Ca and carbon isotope records: Implications for changing Ba composition of Deep Atlantic Water Masses

“…Because deep regeneration is less significant to its cycling, Cd accumulates relatively more slowly in the poorly ventilated Pacific deep waters. While it is unlikely that glacial deep Atlantic ventilation rates were as low as in the modem Pacific, the available •4C evidence is consistent with a glacial decrease in ventilation [Broecker et al, 1990 Results were generated using the ARAND spectral analysis program distributed by Brown Univeristy. Phase angles ( …”