An Interhemispheric Difference in Atmospheric Gaseous Elemental Mercury Isotopes Reveals a New Insight in Oceanic Mercury Emissions

作者：Kaihui Tang, Zhengcheng Song, Xuewu Fu, Yanxu Zhang, Hui Zhang, Ye Sun, Hui Zhang, Xian Wu, Qianwen Deng, Leiming Zhang, Suhaimi Suratman, Tan Hock Seng, Xinbin Feng · 发表于：Journal of Geophysical Research Atmospheres · 年份：2025 · DOI：10.1029/2024jd042178 · 被引用次数：6 · 研究领域：Mercury impact and mitigation studies、Isotope Analysis in Ecology

Abstract Oceanic emission of gaseous elemental mercury (Hg 0 or GEM) is an important source for atmospheric mercury (Hg), but existing estimates of global gross oceanic Hg 0 emissions are highly variable (800–7,220 Mg yr −1 ). This study measured atmospheric GEM concentrations and isotopic compositions at two coastal sites in Terengganu, Malaysia, a region that receives air masses from both hemispheres, during 2019–2021 to diagnose the amount of oceanic Hg 0 emissions. Significantly lower mean (±1sd) concentration (1.28 ± 0.20 ng m −3 ), Δ 199 Hg (−0.23 ± 0.03‰), and Δ 200 Hg (−0.066 ± 0.018‰) and significantly higher δ 202 Hg (0.43 ± 0.12‰) were observed during the wet season when air masses were predominantly from the Southern Hemisphere, compared with those (mean concentration, Δ 199 Hg, Δ 200 Hg, and δ 202 Hg of 1.77 ± 0.09 ng m −3 , −0.17 ± 0.03‰, −0.045 ± 0.023‰, and 0.25 ± 0.11‰, respectively) during the dry season when air masses were predominantly from the Northern Hemisphere, suggesting interhemispheric difference in GEM concentrations and its isotopic compositions. Using a Δ 200 Hg mass balance model, we estimated that the oceanic Hg 0 emissions from Hg II reduction should be below 2,250 ± 891 Mg yr −1 (±1sd), which is at the low‐end range of the literature reported values. We then used the constrained value as emission input to a three‐dimensional atmospheric Hg isotope model and reproduced well the global distributions and interhemispheric gradient of atmospheric...