Modern tropical oceans are experiencing rapid loss of dissolved oxygen due to global warming, yet the mechanisms and consequences of this deoxygenation remain poorly constrained. This session focuses on recent advances in reconstructing paleoredox conditions using redox- sensitive trace elements (Mo, W, U, Re etc.), elemental ratios, and stable isotopes. We welcome studies that include observational datasets from marine sediments, development of novel isotopic and multi-proxy methods, and the application of Mo and W stable isotopes in marine and terrestrial records. Contributions on spatial and temporal redox reconstructions during the Quaternary, and studies linking redox evolution to ocean circulation, sediment/nutrient fluxes, and global climate feedbacks are encouraged. We also invite model-based simulations of oxygen and trace metal cycling. The session aims to integrate proxy development and Earth system modelling to improve our understanding of ocean deoxygenation and its climate linkages.