Forest soils can act as repositories for atmospherically deposited mercury, yet forestry practices can influence mercury mobility and fluxes, food web dynamics, and bioaccumulation processes.
Researchers studied harvested and intact forested catchments in the Pacific Northwest to determine if there is a difference between surface-air mercury fluxes in vegetated versus non-vegetated areas. Results showed that the forested ecosystem largely acted as a repository for deposited elemental mercury throughout most of the year, whereas the harvested catchments emitted mercury to the atmosphere. Differences in solar radiation reaching the soil was the primary driver resulting in a shift from net deposition to emission in harvested catchments. Fluxes of mercury to the atmosphere, which accounted for 97 percent of the differences in mercury sequestered in forested versus harvested catchments, were much larger than runoff fluxes in streams. Providing a better understanding of mercury flux in intact and disturbed soils can aid global-scale model development ahead of the anticipated outcomes of the Minamata Convention on Mercury.
Eckley, C.S., Eagles-Smith, C.A., Tate, M.T., Krabbenhoft, D.P., 2021, Surface-air mercury fluxes and a watershed mass balance in forested and harvested catchments: Environmental Pollution, v. 277, p. 116869, https://doi.org/10.1016/j.envpol.2021.116869.