As global climate continues to warm, melting of glaciers releases a large quantity of mercury (Hg) originally locked in ice into the atmosphere and downstream ecosystems. Here, we show an opposite process that captures atmospheric Hg through glacier-to-vegetation succession. Our study using stable isotope techniques at 3 succession sites on the Tibetan Plateau reveals that evolving vegetation serves as an active "pump" to take up gaseous elemental mercury (Hg0) from the atmosphere. The accelerated uptake enriches the Hg pool size in glacier-retreated areas by a factor of ∼10 compared with the original pool size in the glacier. Through an assessment of Hg source-sink relationship observed in documented glacier-retreated areas in the world (7 sites of tundra/steppe succession and 5 sites of forest succession), we estimate that 400 to 600 Mg of Hg has been accumulated in glacier-retreated areas (5‰ of the global land surface) since the Little Ice Age (∼1850). By 2100, an additional ∼300 Mg of Hg will be sequestered from the atmosphere in glacier-retreated regions globally, which is ∼3 times the total Hg mass loss by meltwater efflux (∼95 Mg) in alpine and subpolar glacier regions. The recapturing of atmospheric Hg by vegetation in glacier-retreated areas is not accounted for in current global Hg models. Similar processes are likely to occur in other regions that experience increased vegetation due to climate or land use changes, which need to be considered in the assessment of global Hg cycling.

中文翻译：

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全球变暖加快了冰川退缩地区大气中汞的吸收。

随着全球气候继续变暖，冰川融化释放出大量原本被固定在冰中的汞（Hg）进入大气和下游生态系统。在这里，我们展示了一个相反的过程，该过程通过冰川到植被的演替来捕获大气中的汞。我们在青藏高原的3个演替地点使用稳定同位素技术进行的研究表明，不断演变的植被是一个活跃的“泵”，可从大气中吸收气态元素汞（Hg0）。与冰川中原始的汞池相比，加速的吸收使冰川退缩地区的汞池富集了约10倍。通过评估在世界上有记载的冰川退缩地区（7个苔原/草原演替地点和5个森林演替地点）观察到的汞源汇关系，我们估计，自小冰河时代（〜1850年）以来，在冰川退缩的地区（全球陆地表面的5‰）已经积累了400至600毫克的汞。到2100年，全球冰川退缩地区将从大气中再吸收约300 Mg汞，这是高山和亚极冰川地区融水外流造成的总汞质量损失（约95 Mg）的3倍。在目前的全球汞模型中，没有考虑到冰川退缩地区植被对大气中汞的吸收。由于气候或土地利用的变化，植被增加的其他地区可能也会发生类似的过程，在评估全球汞循环时需要考虑这些过程。全球将在冰川退缩的地区从大气中再吸收约300 Mg的Hg，这是高山和亚极冰川地区因融水外流造成的总Hg质量损失（〜95 Mg）的3倍。在目前的全球汞模型中，没有考虑到冰川退缩地区植被对大气中汞的吸收。由于气候或土地利用的变化，植被增加的其他地区可能也会发生类似的过程，在评估全球汞循环时需要考虑这些过程。全球将在冰川退缩的地区从大气中再吸收约300 Mg的Hg，这是高山和亚极冰川地区因融水外流造成的总Hg质量损失（〜95 Mg）的3倍。在目前的全球汞模型中，没有考虑到冰川退缩地区植被对大气中汞的吸收。由于气候或土地利用的变化，植被增加的其他地区也可能发生类似的过程，在评估全球汞循环时需要考虑这些过程。