The organic complexation of iron and copper in marine environments

Abstract

Trace metals are required by phytoplankton to form enzymes and proteins involved in photosynthesis, respiration and nutrient assimilation processes. The bioavailability of these trace metals determines ocean productivity and affects the rate of carbon sequestration, which has consequences for O2 production and CO2 uptake. Seawater contains natural organic ligands that complex dissolved iron (dFe) and copper (dCu) with important biochemical implications. The solubility, scavenging, bioavailability, and assimilation rates of dFe and dCu are determined by their complexation, which also impacts their residence time in the dissolved phase. Due to the heterogeneity of dissolved organic matter in seawater, identifying Fe and Cu-binding ligands has been challenging. However, it is possible to determine the concentration and binding strength of these compounds through voltammetric measurements [...]