查看文章

²³¹Pa and ²³⁰Th are removed from the water column by a process of reversible scavenging which quickly removes ²³⁰Th to the sediment. ²³¹Pa is less efficiently scavenged onto particles than ²³⁰Th and is therefore more effectively transported via advection and diffusion before it reaches the ocean sediment. This study combines particle fields (dust, opal, CaCO₃, POC) derived from observations with the Bern3D intermediate complexity ocean model and an equilibrium-scavenging model for isotopes. The equilibrium partition coefficient for particulate versus dissolved isotope activity is varied with particle type. The model can explain many of the features of the global ²³¹Pa and ²³⁰Th distribution. The success of such a simple model at representing the global pattern of ²³¹Pa/²³⁰Th activity ratio supports the use of this proxy in paleoceanographic studies. We use the model to address the controversy concerning …