On new developments in accelerator mass spectrometry and how they promote our understanding of global carbon cycle dynamics during the last deglaciation

Ocean-atmosphere 14C disequilibria of the surface and deep ocean reflect past changes in the efficiency of ocean-atmosphere CO2 exchange and ocean mixing, while it may also be related to variations in global-ocean respired carbon content. A full assessment of the oceanic mechanisms controlling deglacial changes in atmospheric CO2 is complicated by a lack of high-resolution 14C ventilation age estimates from the Southern Ocean and other key regions due to low foraminiferal abundances in marine sediments in those areas. Here we present high-resolution deglacial 14C ventilation age records from key sites in the Atlantic and Indian Sector of the Southern Ocean obtained by radiocarbon analyses of small benthic and planktic foraminiferal samples (< 1 mg CaCO3) with the UniBe Mini-Carbon Dating System (MICADAS). Our analyses specifically circumvent foraminiferal sample size requirements related to …