Paleonutrient data analysis of the glacial Atlantic using an adjoint ocean general circulation model

In this study we assimilate measurements of stable carbon isotope compositions delta(13)C and the ratio of cadmium to calcium (Cd/Ca) concentrations from marine sediments into an ocean general circulation model to reconstruct the flow field of the deep-sea during the last glacial maximum (LGM) 21,000 years ago. The results of the assimilation confirm that the southward how of North Atlantic Deep Water was shallower during the LGM and this was accompanied by a strong source of glacial North Atlantic Intermediate Water. The optimized glacial flow field in the Southern Ocean is consistent with the Cd/Ca measurements but can not explain delta(13)C changes, suggesting a breakdown of the glacial phosphate-delta(13)C relationship