资源环境科技发展态势分析平台

Deep oceanic circulation regulates seafloor CaCO₃ accumulation by transporting atmospheric CO₂ to depth and then transferring it with respired CO₂, along the global ocean conveyor belt. This creates the shallowing trend of CaCO₃ preservation from the Atlantic to the Pacific Oceans. The thermohaline flow can be, however, complex on a basin-wide scale; here, we use a state-of-the-art data compilation and a carbonate accumulation/dissolution model to explain the CaCO₃ distribution within the basins of the Southwestern Atlantic Ocean. Our results demonstrate that different currents foster systematically dissimilar CaCO₃ preservations within these connected ocean basins. The more undersaturated, faster moving, northward-flowing Antarctic Bottom Water readily dissolves more CaCO₃ than the southward-flowing North Atlantic Deep Water. We are able to predict quantitatively these observations, based on benthic carbonate chemistry and mass-transfer rates. Our model and CaCO₃ records in such basins have the potential to provide new understanding about deep-ocean circulation of the past.