Isotopic evolution of dissolved Ni, Cu, and Zn along the Kuroshio through the East China Sea

In this study, we have investigated the evolution of concentrations and isotope ratios of dissolved nickel (Ni), copper (Cu), and zinc (Zn) from the North Equatorial Current in the western North Pacific to the Kuroshio in the East China Sea, where the inputs of anthropogenic and lithogenic materials through riverine and aeolian pathways are relatively high. The concentrations and isotope ratios for Ni, Cu, and Zn in the deep water of the East China Sea are similar to those of the western North Pacific. The concentrations of Ni, Cu, and Zn in the Changjiang diluted water (<34.0 of salinity) are 3.0–4.1 nmol/kg, 2.0–2.7 nmol/kg, and 0.5–1.1 nmol/kg, respectively, which are significantly higher than those in the surface water of the western North Pacific, thereby indicating the impact of the riverine input. In the Changjiang diluted water, isotope ratios of Ni range from +0.8 to +1.4‰, which is lower than +1.7‰ observed in the surface water (