We present the first measurements of the isotopic composition of mercury (Hg) in fogwater, measured in samples collected across coastal California. Coastal California fogwater samples exhibit a relatively narrow range of Hg isotopic compositions {δ²⁰²Hg = −0.60‰ to 0.38‰, average of −0.10 ± 0.33‰ [one standard deviation (1SD)]; Δ¹⁹⁹Hg = 0.04–0.75‰, average of 0.28 ± 0.17‰ (1SD); Δ²⁰⁰Hg = −0.16‰ to 0.24‰, average of 0.08 ± 0.10‰ (1SD)}. The isotopic composition of fogwater samples did not exhibit any spatial trends, either with distance from the Pacific Ocean coastline or with the latitude of sampling locations. The Hg isotopic composition of coastal California fogwater samples is not significantly different from that of precipitation collected across coastal California and the North Pacific, suggesting that marine-derived atmospheric Hg has a relatively homogeneous isotopic composition across the North Pacific. Fogwater samples exhibit a Δ¹⁹⁹Hg/Δ²⁰¹Hg slope of 1.03 consistent with Hg(II) photoreduction, highlighting the importance of photoreduction mechanisms in controlling the odd-MIF isotopic composition of atmospheric Hg wet deposition. Overall, the need for an improved understanding of the processes that control atmospheric Hg deposition is revealed by this data set, as such knowledge will be required to more accurately model global atmospheric Hg cycling.

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加利福尼亚沿海雾水中汞的同位素组成

我们介绍了雾水中汞（Hg）的同位素组成的首次测量，该测量是在整个加利福尼亚州沿海地区收集的样品中进行的。沿海加利福尼亚fogwater样品表现出相对窄的范围内的汞同位素组成{δ的²⁰²汞柱= -0.60‰至0.38‰，平均-0.10±0.33‰[一个标准偏差（1SD）]的; Δ ¹⁹⁹汞柱= 0.04-0.75‰，平均为0.28±0.17‰（1SD）; Δ ²⁰⁰汞= -0.16‰至0.24‰，平均值为0.08±0.10‰（1SD）}。雾水样品的同位素组成没有表现出任何空间趋势，无论距太平洋海岸线的距离或采样位置的纬度都没有。加利福尼亚沿海雾水样品的汞同位素组成与加利福尼亚沿海和北太平洋地区收集的降水没有显着差异，这表明来自海洋的大气汞在北太平洋地区具有相对均一的同位素组成。Fogwater样品显示出Δ ¹⁹⁹汞柱/Δ ²⁰¹Hg斜率为1.03，与Hg（II）光还原一致，突出了光还原机制在控制大气Hg湿沉降的奇数MIF同位素组成中的重要性。总体而言，该数据集表明需要更好地了解控制大气中汞沉积的过程，因为将需要此类知识来更准确地对全球大气中汞循环进行建模。