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Mercury stable isotopes constrain atmospheric sources to the ocean

Jiskra, Martin and Heimbürger-Boavida, Lars-Eric and Desgranges, Marie-Maëlle and Petrova, Mariia V. and Dufour, Aurélie and Ferreira-Araujo, Beatriz and Masbou, Jérémy and Chmeleff, Jérôme and Thyssen, Melilotus and Point, David and Sonke, Jeroen E.. (2021) Mercury stable isotopes constrain atmospheric sources to the ocean. Nature, 597 (7878). pp. 678-682.

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Abstract

Human exposure to toxic mercury (Hg) is dominated by the consumption of seafood; 1,2; . Earth system models suggest that Hg in marine ecosystems is supplied by atmospheric wet and dry Hg(II) deposition, with a three times smaller contribution from gaseous Hg(0) uptake; 3,4; . Observations of marine Hg(II) deposition and Hg(0) gas exchange are sparse, however; 5; , leaving the suggested importance of Hg(II) deposition; 6; ill-constrained. Here we present the first Hg stable isotope measurements of total Hg (tHg) in surface and deep Atlantic and Mediterranean seawater and use them to quantify atmospheric Hg deposition pathways. We observe overall similar tHg isotope compositions, with median Δ; 200; Hg signatures of 0.02‰, lying in between atmospheric Hg(0) and Hg(II) deposition end-members. We use a Δ; 200; Hg isotope mass balance to estimate that seawater tHg can be explained by the mixing of 42% (median; interquartile range, 24-50%) atmospheric Hg(II) gross deposition and 58% (50-76%) Hg(0) gross uptake. We measure and compile additional, global marine Hg isotope data including particulate Hg, sediments and biota and observe a latitudinal Δ; 200; Hg gradient that indicates larger ocean Hg(0) uptake at high latitudes. Our findings suggest that global atmospheric Hg(0) uptake by the oceans is equal to Hg(II) deposition, which has implications for our understanding of atmospheric Hg dispersal and marine ecosystem recovery.
Faculties and Departments:05 Faculty of Science > Departement Umweltwissenschaften > Geowissenschaften > Umweltgeowissenschaften (Alewell)
UniBasel Contributors:Jiskra, Martin
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:Nature Research
ISSN:0028-0836
e-ISSN:1476-4687
Note:Publication type according to Uni Basel Research Database: Journal article
Language:English
Identification Number:
edoc DOI:
Last Modified:12 Oct 2021 08:29
Deposited On:12 Oct 2021 08:29

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