The distribution of bismuth in the Western Pacific and its characteristic

Abstract

Trace elements in the ocean show a vertical distribution that sharply reflects various material circulation processes and is very useful for elucidation of material circulation.Bismuth, which is a trace element, can be expected as an important tracer of marine material circulation occurring on a relatively short time scale because the residence time in the ocean is as short as about 20 years (Lee et al., 1985/1986). However, Bi concentration in open ocean water is extremely low and it is difficult to precisely quantify it, and the number of reported worldwide is poor. Therefore, in this research, using the already established analysis method (Norisuye & Sohrin, 2012), our purpose is elucidate the concentration distribution of dissolved Bi in the Western Pacific Ocean sampled by Hakuho Maru KH-14-6 cruise, KH-11-7 cruise and Shinsei Maru KS-13-T3 cruise. At the station in the western North Pacific, it showed a remarkable concentration maximum in the subsurface layer of the North Pacific subtropical mode water (NPSTMW). It was found that Bi concentration of each layer in the southern hemisphere stations is lower than that in the northern hemisphere. This study is the first in the data of the Southern Hemisphere.