The study indicates that a significant portion of the mercury entering terrestrial ecosystems is chemically activated and transported globally in the stratosphere.
So far, both the chemical reactivity and the global transport of mercury have been considered to occur in the troposphere, the lower layer of the atmosphere in contact with the surface. However, this work shows that this is not the case, revealing that nearly a third of the mercury that enters the terrestrial ecosystem has reacted in the stratosphere (from 12 to 40 km high), due to the unique characteristics of the stratospheric photochemical environment that accelerate the oxidation processes of mercury, leading to the formation of a ring of oxidized mercury that would surround the planet.
In addition, the study shows for the first time that the circulation of air in this layer of the atmosphere works like a global conveyor belt, in which large quantities of gaseous mercury are transported from intensely contaminated areas to the most isolated and remote places, such as the polar regions. It also predicts that climate change will increase the stratospheric transport of mercury.
Alfonso Saiz-Lopez, Carlos A. Cuevas, A. Ulises Acuña, Juan A. Añel, Anoop S. Mahajan, Laura de la Torre, Wuhu Feng, Juan Z. Dávalos, Daniel Roca-Sanjuán, Douglas E. Kinnison, Javier Carmona-García, Rafael P. Fernandez, Qinyi Li, Jeroen E. Sonke, Aryeh Feinberg, Juan Carlos Gómez Martín, Julián Villamayor, Peng Zhang, Yanxu Zhang, Christopher S. Blaszczak-Boxe, Oleg Travnikov, Feiyue Wang, Johannes Bieser, Joseph S. Francisco and John M. C. Plane. Role of the stratosphere in the global mercury cycle. Science Advances. DOI: 10.1126/sciadv.ads1459
https://www.science.org/doi/epdf/10.1126/sciadv.ads1459