LiveZilla Live Chat Software

Constellation, le dépôt institutionnel de l'Université du Québec à Chicoutimi

Photodemethylation of methylmercury in Eastern Canadian Arctic thaw pond and lake ecosystems

Girard Catherine, Leclerc Maxime et Amyot Marc. (2016). Photodemethylation of methylmercury in Eastern Canadian Arctic thaw pond and lake ecosystems. Environmental Science & Technology, 50, (7), p. 3511-3520.

[img]
Prévisualisation
PDF - Version acceptée
8MB
[img]
Prévisualisation
PDF (Supporting Information) - Matériel supplémentaire
1MB

URL officielle: http://dx.doi.org/doi:10.1021/acs.est.5b04921

Résumé

Permafrost thaw ponds of the warming Eastern Canadian Arctic are major landscape constituents and often display high levels of methylmercury (MeHg). We examined photodegradation potentials in high-dissolved organic matter (DOC) thaw ponds on Bylot Island (BYL) and a low-DOC oligotrophic lake on Cornwallis Island (Char Lake). In BYL, the ambient MeHg photodemethylation (PD) rate over 48 h of solar exposure was 6.1 × 10–3 m2E–1, and the rate in MeHg amended samples was 9.3 × 10–3 m2 E–1. In contrast, in low-DOC Char Lake, PD was only observed in the first 12 h, which suggests that PD may not be an important loss process in polar desert lakes. Thioglycolic acid addition slowed PD, while glutathione and chlorides did not impact northern PD rates. During an ecosystem-wide experiment conducted in a covered BYL pond, there was neither net MeHg increase in the dark nor loss attributable to PD following re-exposure to sunlight. We propose that high-DOC Arctic thaw ponds are more prone to MeHg PD than nearby oligotrophic lakes, likely through photoproduction of reactive species rather than via thiol complexation. However, at the ecosystem level, these ponds, which are widespread through the Arctic, remain likely sources of MeHg for neighboring systems.

Type de document:Article publié dans une revue avec comité d'évaluation
ISSN:0013-936X
Volume:50
Numéro:7
Pages:p. 3511-3520
Version évaluée par les pairs:Oui
Date:2016
Identifiant unique:10.1021/acs.est.5b04921
Sujets:Sciences naturelles et génie > Sciences appliquées > Climatologie et météorologie
Sciences naturelles et génie > Sciences appliquées > Eau et environnement
Sciences naturelles et génie > Sciences naturelles > Chimie
Département, module, service et unité de recherche:Départements et modules > Département des sciences fondamentales
Mots-clés:Photodemethylation, methylmercury, thaw ponds, Arctic, organic matter, climate change, biogeochemistry, photodéméthylation, méthylmercure, eaux de fonte, arctique, matière organique, changement climatique, biogéochimie
Déposé le:23 juill. 2021 15:55
Dernière modification:23 juill. 2021 15:55
Afficher les statistiques de telechargements

Éditer le document (administrateurs uniquement)

Creative Commons LicenseSauf indication contraire, les documents archivés dans Constellation sont rendus disponibles selon les termes de la licence Creative Commons "Paternité, pas d'utilisation commerciale, pas de modification" 2.5 Canada.

Bibliothèque Paul-Émile-Boulet, UQAC
555, boulevard de l'Université
Chicoutimi (Québec)  CANADA G7H 2B1
418 545-5011, poste 5630