Kohen is a marine biogeochemist who is a senior staff scientist at ONC. He is focussed on supporting interdisciplinary projects related to marine biogeochemical cycling, ocean acidification, ocean deoxygenation, and climate dynamics. He earned his PhD from the University of British Columbia in 2019 and his MSc from the University of Toronto in 2013. His PhD thesis was focussed on reconstructing the history of oxygen in the ocean-atmosphere system and its links to the coevolution of life and climate. He worked on developing emerging and widely used geochemical tools that allow for more refined interpretations of Earth’s surface conditions captured in the rock record through time. Kohen conducted his post-doctoral research at the University of Hong Kong, where he worked on integrating geochemical data with conceptual computer models to understand the drivers, rates, and magnitude of ocean deoxygenation in Earth’s past and its connections to mass extinction events and climate change on different timescales. His current research interests are broad and include: ocean deoxygenation on varying timescales, the connections between climate and biogeochemical cycles, ocean chemistry and acidification, the role of microbes in marine biogeochemical cycles, the composition of marine sediments, and developing new and innovative biogeochemical proxy tools.