Isotopic Characterization of Mercury Atmosphere-Foliage and Atmosphere-Soil Exchange in a Swiss Subalpine Coniferous Forest.
Environ Sci Technol
; 57(42): 15892-15903, 2023 10 24.
Article
in En
| MEDLINE
| ID: mdl-37788478
ABSTRACT
To understand the role of vegetation and soil in regulating atmospheric Hg0, exchange fluxes and isotope signatures of Hg were characterized using a dynamic flux bag/chamber at the atmosphere-foliage/soil interfaces at the Davos-Seehornwald forest, Switzerland. The foliage was a net Hg0 sink and took up preferentially the light Hg isotopes, consequently resulting in large shifts (-3.27) in δ202Hg values. The soil served mostly as net sources of atmospheric Hg0 with higher Hg0 emission from the moss-covered soils than from bare soils. The negative shift of δ202Hg and Δ199Hg values of the efflux air relative to ambient air and the Δ199Hg/Δ201Hg ratio among ambient air, efflux air, and soil pore gas highlight that Hg0 re-emission was strongly constrained by soil pore gas evasion together with microbial reduction. The isotopic mass balance model indicates 8.4 times higher Hg0 emission caused by pore gas evasion than surface soil photoreduction. Deposition of atmospheric Hg0 to soil was noticeably 3.2 times higher than that to foliage, reflecting the high significance of the soil to influence atmospheric Hg0 isotope signatures. This study improves our understanding of Hg atmosphere-foliage/soil exchange in subalpine coniferous forests, which is indispensable in the model assessment of forest Hg biogeochemical cycling.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Mercury
Country/Region as subject:
Europa
Language:
En
Journal:
Environ Sci Technol
Year:
2023
Document type:
Article
Affiliation country: