Near surface oxidation of elemental mercury leads to mercury exposure in the Arctic Ocean biota.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39217169.
- Also identified by DOI 10.1038/s41467-024-51852-2 and PMC identifier 11365953.
- Licence recorded as CC BY-NC-ND.
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Abstract
Atmospheric mercury (Hg(0), Hg(II)) and riverine exported Hg (Hg(II)) are proposed as important Hg sources to the Arctic Ocean. As plankton cannot passively uptake Hg(0), gaseous Hg(0) has to be oxidized to be bioavailable. Here, we measured Hg isotope ratios in zooplankton, Arctic cod, total gaseous Hg, sediment, seawater, and snowpack from the Bering Strait, the Chukchi Sea, and the Beaufort Sea. The Δ<sup>200</sup>Hg, used to differentiate between Hg(0) and Hg(II), shows, on average, 70% of Hg(0) in all biota and differs with seawater Δ<sup>200</sup>Hg (Hg(II)). Since Δ<sup>200</sup>Hg anomalies occur via tropospheric Hg(0) oxidation, we propose that near-surface Hg(0) oxidation via terrestrial vegetation, coastally evaded halogens, and sea salt aerosols, which preserve Δ<sup>200</sup>Hg of Hg(0) upon oxidation, supply bioavailable Hg(II) pools in seawater. Our study highlights sources and pathways in which Hg(0) poses potential ecological risks to the Arctic Ocean biota.