Photodemethylation of methylmercury in Eastern Canadian Arctic thaw pond and lake ecosystems
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 Corn...
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ftunivquebecchic:oai:constellation.uqac.ca:7688 2023-05-15T14:25:48+02:00 Photodemethylation of methylmercury in Eastern Canadian Arctic thaw pond and lake ecosystems Girard, Catherine Leclerc, Maxime Amyot, Marc 2016 application/pdf https://constellation.uqac.ca/7688/1/Girard_et_al_2016_EnvScTech_accepted.pdf https://constellation.uqac.ca/7688/2/Girard_et_al_2016_EnvScTech_suppl.pdf en eng https://constellation.uqac.ca/7688/ http://dx.doi.org/doi:10.1021/acs.est.5b04921 doi:10.1021/acs.est.5b04921 https://constellation.uqac.ca/7688/1/Girard_et_al_2016_EnvScTech_accepted.pdf https://constellation.uqac.ca/7688/2/Girard_et_al_2016_EnvScTech_suppl.pdf 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. Climatologie et météorologie Eau et environnement Chimie Article publié dans une revue avec comité d'évaluation PeerReviewed 2016 ftunivquebecchic https://doi.org/10.1021/acs.est.5b04921 2021-07-24T22:13:11Z 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. Text Arctic Arctic Bylot Island Cornwallis Island permafrost polar desert Université du Québec à Chicoutimi (UQAC): Constellation Arctic Bylot Island Cornwallis ENVELOPE(-54.464,-54.464,-61.072,-61.072) Cornwallis Island ENVELOPE(-95.001,-95.001,75.135,75.135) Environmental Science & Technology 50 7 3511 3520 |
institution |
Open Polar |
collection |
Université du Québec à Chicoutimi (UQAC): Constellation |
op_collection_id |
ftunivquebecchic |
language |
English |
topic |
Climatologie et météorologie Eau et environnement Chimie |
spellingShingle |
Climatologie et météorologie Eau et environnement Chimie Girard, Catherine Leclerc, Maxime Amyot, Marc Photodemethylation of methylmercury in Eastern Canadian Arctic thaw pond and lake ecosystems |
topic_facet |
Climatologie et météorologie Eau et environnement Chimie |
description |
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. |
format |
Text |
author |
Girard, Catherine Leclerc, Maxime Amyot, Marc |
author_facet |
Girard, Catherine Leclerc, Maxime Amyot, Marc |
author_sort |
Girard, Catherine |
title |
Photodemethylation of methylmercury in Eastern Canadian Arctic thaw pond and lake ecosystems |
title_short |
Photodemethylation of methylmercury in Eastern Canadian Arctic thaw pond and lake ecosystems |
title_full |
Photodemethylation of methylmercury in Eastern Canadian Arctic thaw pond and lake ecosystems |
title_fullStr |
Photodemethylation of methylmercury in Eastern Canadian Arctic thaw pond and lake ecosystems |
title_full_unstemmed |
Photodemethylation of methylmercury in Eastern Canadian Arctic thaw pond and lake ecosystems |
title_sort |
photodemethylation of methylmercury in eastern canadian arctic thaw pond and lake ecosystems |
publishDate |
2016 |
url |
https://constellation.uqac.ca/7688/1/Girard_et_al_2016_EnvScTech_accepted.pdf https://constellation.uqac.ca/7688/2/Girard_et_al_2016_EnvScTech_suppl.pdf |
long_lat |
ENVELOPE(-54.464,-54.464,-61.072,-61.072) ENVELOPE(-95.001,-95.001,75.135,75.135) |
geographic |
Arctic Bylot Island Cornwallis Cornwallis Island |
geographic_facet |
Arctic Bylot Island Cornwallis Cornwallis Island |
genre |
Arctic Arctic Bylot Island Cornwallis Island permafrost polar desert |
genre_facet |
Arctic Arctic Bylot Island Cornwallis Island permafrost polar desert |
op_relation |
https://constellation.uqac.ca/7688/ http://dx.doi.org/doi:10.1021/acs.est.5b04921 doi:10.1021/acs.est.5b04921 https://constellation.uqac.ca/7688/1/Girard_et_al_2016_EnvScTech_accepted.pdf https://constellation.uqac.ca/7688/2/Girard_et_al_2016_EnvScTech_suppl.pdf 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. |
op_doi |
https://doi.org/10.1021/acs.est.5b04921 |
container_title |
Environmental Science & Technology |
container_volume |
50 |
container_issue |
7 |
container_start_page |
3511 |
op_container_end_page |
3520 |
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1766298257015701504 |