Dalton Hardisty's work has been focused on placing constraints on how ocean chemistry and early animal life co-evolved with the emergence and proliferation of oxygenic photosynthesis over billion year timescales. Additional work focuses on determining the more recent pre-anthropogenic history of seawater oxygen in coastal settings in order to provide a perspective on natural variable and the impacts and consequences of humans on ocean chemistry. These questions ultimately require studies of the geochemistry of modern seawater and sediments, determining how post-depositional processes (diagenesis) might alter sediment geochemistry, as well as applications toward using the geochemistry of sedimentary rocks to reconstruct how ancient seawater contrasted with that of.