Mechanisms controlling the abyssal transport of anthropogenic carbon in the North Atlantic

Since the industrial revolution, human activities have emitted large amount of anthropogenic carbon (C_ant) into the atmosphere through the burning of fossil fuel, the production of cement and land-use change. Via air-sea gas exchange, the ocean absorbs roughly a third of C_ant, meaning that C_ant is an additional source of carbon for the ocean. In particular, the North Atlantic is known to be a region with a high storage capacity of C_ant. Whereas the distribution of C_ant in the upper layers of the North Atlantic is well documented, its transport to the abyssal ocean and the mechanisms behind its deep redistribution remain scarcely described. To shed light on this research gap, we use a database provided by ~70 Deep-Argo floats equipped with oxygen sensors and located in the North Atlantic that allow us to explore the deep pathways of C_ant. First, the macronutrients and carbon variables (pH, total alkalinity, total inorganic carbon and pCO₂) are estimated with bayesian neural networks (CANYON-B and CONTENT) from the temperature, salinity and oxygen data of the floats. Second, C_ant concentrations in the water column are then estimated with back-calculation methods. Here we present the first results of our study.