Redox sensitive elements (RSE) are typically found in higher concentrations in sediments from oxygen-depleted environments compared to their detrital levels. While modern ocean waters are generally well-oxygenated, oxygen-deprived settings are found in isolated basins and high-productivity zones. Historically, oxygen-depleted environments were more prevalent on early Earth. The degree of RSE enrichment in ancient sediments indicates the oxygen-poor conditions of the sedimentary environment. However, there is a need for more precise tools to describe ancient environments, necessitating extensive interdisciplinary research on the mechanisms of RSE accumulation in anoxic sediments. A comprehensive understanding of RSE behavior in anoxic settings requires detailed knowledge of the chemistry involved, not just in anoxic environments. This session presents new research on RSE using various techniques (mass spectrometry, isotopic analysis, elemental speciation, solid phase characterization, radiochemical methods) across different environments (lakes, rivers, ocean) with varying oxygen concentrations and penetration depths in the water column and sediments. We encourage contributions that employ interdisciplinary and multi-analytical approaches to describe RSE sedimentary phases, RSE speciation in aqueous phases, RSE cycling at the oxia/anoxia boundary, and overall research that advances understanding of the (bio)geochemistry of RSE.