Reinterpretation of oceanic 230Th profiles based on decadal export productivity (2003–2010)

摘要

Understanding ²³⁰Th distributions in the global ocean is important to support and guide the use of this important radioactive nuclide in multiple aspects of oceanographic research, and this issue is now revisited. Based on estimates of export productivity (EP) over 2003–2010 and assuming ²³⁰Th scavenging at equilibrium at seven Pacific stations where linear ²³⁰Th profiles are found, an empirical equilibrium-state ²³⁰Th-scavenging versus EP correlation is established. This correlation demonstrates the relationship between ²³⁰Th-scavenging intensity and EP in the absence of advection. With this correlation, other ²³⁰Th profiles from global oceans are reinterpreted. My findings provide alternative explanations of signals carried by ²³⁰Th distributions with regard to advection, by a reassessment of the ²³⁰Th deficits in deep waters. Such an equilibrium-state ²³⁰Th-scavenging versus EP correlation provides a basis for convenient parameterization for use in 3D modeling studies of the ²³⁰Th distributions.