Overlooked riverine contributions of dissolved neodymium and hafnium to the Amazon estuary and oceans.

ABSTRACT: The Amazon River accounts for 20% of global freshwater runoff and supplies vital trace metals to the Atlantic Ocean. Suspended particles within its plume are thought to partially dissolve, constituting a large potential source of metals, which is, however, not well constrained. Here we used combined neodymium (Nd) and hafnium (Hf) isotopes to disprove the release of Nd and Hf from particles as the cause of the observed dissolved concentration increases and isotopic variability across the plume. Instead, the changes reflect admixture of nearby Pará River freshwater with exceptionally high dissolved Nd and Hf concentrations contributing 45-100% of the riverine fraction to the southern and outer estuary. This result led us to develop an empirical relationship between riverine Nd concentration

SUBMITTER: Xu A 

PROVIDER: S-EPMC10338505 | biostudies-literature | 2023 Jul

REPOSITORIES: biostudies-literature