The Riverine Delivery of Trace Metals and their Isotopes to Oceans: New Insights from Mo, Ni, Fe, and Zn in the Amazon Basin

The transition metals (e.g., Mo, Zn, Ni, Fe, Cu) are integral in surface Earth biogeochemical cycling. Ubiquitous in the environment, their redox sensitivity limits their mobility and gives them central roles in metabolic processes, intimately linking the geosphere with the biosphere. This, coupled with their ability to be archived in the sedimentary record, makes transition metals and their isotopes attractive tracers of biological evolution and oceanic redox in Earth history. Exploitation of this sedimentary archive relies critically on understanding controls of the modern oceanic budgets of these metals and their isotopes. The motivation for this work stems from the observation that, for many transition metals, the dissolved load (