Mercury Stable Isotope Composition of Lichens and Mosses from Northern Eurasia Reveals Hg Deposition Pathways and Sources

• Main Authors: Jeroen E. Sonke (1472950), Vladimir P. Shevchenko (14279572), Jonathan Prunier (14279575), Ruoyu Sun (1785805), Anatoly S. Prokushkin (14279578), Oleg S. Pokrovsky (821057)
• Format: Dataset
• Language: unknown
• Published: 2022
• Subjects: Microbiology; Cell Biology; Genetics; Molecular Biology; Physiology; Pharmacology; Ecology; Environmental Sciences not elsewhere classified; Biological Sciences not elsewhere classified; Chemical Sciences not elsewhere classified; remote locations across; isotopic composition (<; 7700 ng g; 74 ng g; 35 ng g; 300 km inland; 243 ng g; inland terricolous lichen; regional soil hg; preferentially accumulate hg; identifies preferential hg; hg signatures suggest; hg isotope variability; ii </ sup; 72 ° n; 202 </ sup; 200 </ sup; 199 </ sup; hg deposition pathways; dry deposition compared; colocated terricolous lichens; arctic ocean shore; epiphytic tree lichens; atmospheric hg deposition; terricolous lichens near; 15 ‰; similar; 0 </ sup; n </; dry deposition; terricolous lichens; atmospheric hg; tree lichens; total hg; oxidized hg; near zero; 1 ‰; − 3; substantially higher; sources mercury; Arctic; Arctic Ocean
• Online Access: https://doi.org/10.1021/acsearthspacechem.2c00297.s001

Mercury (Hg) concentrations in lichens and mosses can be used as surrogates for atmospheric Hg deposition to continental surfaces. In this study, we collected and analyzed Hg concentrations ( n = 334) and isotopic composition ( n = 67) of epiphytic tree lichens and terricolous lichens and mosses from remote locations across the Eurasian Arctic and sub-Arctic (50 to 72° N, 30 to 180° E). The total Hg (THg) concentrations ranged from 13 to 7700 ng g –1 . Epiphytic tree lichens had significantly higher median THg levels (243 ng g –1 ) than terricolous lichens (35 ng g –1 ) and mosses (74 ng g –1 ). THg is substantially higher in both tree lichens and terricolous lichens near the Arctic Ocean shore and up to 300 km inland. The combined δ 202 Hg, Δ 199 Hg, and Δ 200 Hg signatures suggest that the elevated coastal Hg levels are delivered by marine air masses rich in gaseous and particulate-oxidized Hg II forms, such as HgBr 2 . Similar to other vegetation Hg isotope studies, inland terricolous lichen and moss Δ 200 Hg are near zero, indicating a dominant (63%) atmospheric Hg 0 origin followed by Hg II wet and dry deposition. Inland tree lichens carry a more positive Δ 200 Hg of 0.15‰, similar to the atmospheric Hg II end-member, suggesting that they preferentially accumulate Hg II wet and dry deposition compared to colocated terricolous lichens. Mosses from the European sub-Arctic show a low δ 202 Hg of −3.1‰, which we speculate to result from regional soil Hg 0 emissions that are recaptured by mosses. Overall, the Hg isotope variability of mosses and lichens reveals latitudinal gradients in Hg deposition pathways and identifies preferential Hg 0 or Hg II uptake.