[A-OS17] Ocean circulation and material cycle in coastal seas

[AOS17-P07] Time-series variations for Gaseous Elemental Mercury (GEM) from northern Pacific to the Arctic Ocean in the Summer to early Autumn of 2022

*Osamu Nagafuchi¹, Koyomi Nakazawa², Kazuki Oura³, Ken’ichi Shinozuka⁴, Tetsuo Sueyoshi⁶, Masanobu YamamotoYamamoto⁵, Tomoaki Watanabe⁷, Akihiro Mitsui⁷ (1.Fukuoka Institute of Techology, 2.Toyama Prefectural University, 3.Graduate school of Toyama Prefectural University, 4.Gifu University, 5.Hokkaido University, 6.JAMSTEC, 7.Nippon Instruments Corporation)

Keywords:Gaseous Elemental Mercury, marine boundary layer, MIRAI cruise, Arctic ocean

Measurements of gaseous elemental mercury (GEM) in the marine boundary layer were performed using AM-6F with CVAFS method during MIRAI cruise from 12 August to 29 September 2022. GEM concentrations varied from 0.56 to 2.02 ng/m3 (n=980); the average value (1.01±0.24 ng/m3) was lower than the background range of the Northern Hemisphere (1.5~1.7ng/m3) and corresponded to the background concentrations of the Southern Hemisphere (1.1~1.3 ng/m3). However, each sea area had its own characteristics. The average GEM concentrations in Arctic Sea, Bering Sea and Sea of Okhotsk were 0.89 ± 0.12 ng/m3, 1.07 ± 0.13 ng/m3, 1.40 ± 0.27 ng/m3, respectively. Thus, the concentration tended to decrease as one moved northern sea area.