This $708,182 National Science Foundation Project Grant under the Geosciences program (CFDA 47.050) will fund research at Colorado State University from September 1, 2022 to August 31, 2025. The research aims to advance understanding of the causal pathways governing the interocean exchange between the Indian, South Atlantic, and Southern Oceans south of Africa. The project will utilize state-of-the-art nonlinear data assimilation, ocean modeling, observational datasets, and causal discovery methods to determine the physical processes responsible for the interocean exchange and how they interact nonlinearly. Key outcomes will include a 30-year reanalysis of the region incorporating all available observations and quantification of the direct and interacting contributions of processes such as Agulhas eddies and dipoles. Results seek to answer overarching questions about the controlling physical processes and their interactions in modulating the interocean exchange, with potential applications to other oceanographic and geoscience challenges.