Distribution of Nine Bioactive Trace Metals (Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb) in the Western North Pacific Ocean

Abstract

The western North Pacific Ocean, which includes the confluence of the Oyashio and Kuroshio currents, is characterized by a complex water mass structure and also contains many hydrothermal vents formed by subduction. Moreover, the influences of atmospheric deposition of dust from the continent and particle supply from continental shelf and coastal origins are observed. In this study, we report the distribution of dissolved fractions of nine bioactive trace metals (Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) in seawater samples collected during the GEOTRACES JAPAN KH-22-7 cruise, which was conducted from July to August 2022. Fe was supplied from terrestrial sources, while Co, Cd, and Zn were transported by the North Pacific Intermediate Water (NPIW). Fe and Mn maxim were observed at a 2600 m depth at 10-degree North, which was suggested as the influence of hydrothermal plumes originating from the Mariana Arc.