Depth distribution of Zr and Nb in seawater: The potential role of colloids or organic complexation to explain non-scavenging-type behavior

Analysis of the size-fractionated Pacific samples ruled out a significant colloidal (0.015 μm-0.2 μm) component as host for Zr and Nb. We suggest that dissolved Zr and Nb might be stabilized by organic complexation in deep waters because both elements form very stable complexes with organic molecules such as siderophores.