RECONSTRUCTING OCEANIC REDOX CONDITIONS THROUGHOUT THE PHANEROZOIC

The evolutionary trajectory and extinction dynamics of marine biota are closely linked to variations in oceanic redox conditions, which are influenced by the geological history of atmospheric oxygen, along with long-term patterns of weathering and organic carbon burial on the seafloor. Previous box models have often oversimplified the complex interactions within the ocean's interior. In this study, we utilize the Community Earth System Model (CESM) with an offline diagnostic biogeochemistry model to reconstruct the evolution of oceanic redox conditions throughout the Phanerozoic. We investigate the role of critical oceanic processes such as continental configurations, circulation patterns, remineralization depths, and phosphorus inventories in modulating seafloor organic carbon burial. These factors, together with continental weathering fluxes, are integral to our reconstruction of the long-term three-dimensional redox conditions of the ocean. Our results align closely with reconstructions of Phanerozoic upper ocean redox states based on I/Ca proxies, providing new insights into the mechanisms that have driven marine evolutionary history.