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...
Published in: | Environmental Science & Technology |
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2016
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Online Access: | http://hdl.handle.net/1866/19172 https://doi.org/10.1021/acs.est.5b04921 |
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ftunivmontreal:oai:papyrus.bib.umontreal.ca:1866/19172 2023-05-15T14:42:01+02:00 Photodemethylation of methylmercury in Eastern Canadian Arctic thaw pond and lake ecosystems Girard, Catherine Leclerc, Maxime Amyot, Marc Université de Montréal. Faculté des arts et des sciences. Département de sciences biologiques 2016-04-05 http://hdl.handle.net/1866/19172 https://doi.org/10.1021/acs.est.5b04921 eng eng http://hdl.handle.net/1866/19172 doi:10.1021/acs.est.5b04921 Photodemethylation Methylmercury Thaw ponds Arctic Organic matter Climate change Biogeochemistry journal article article 2016 ftunivmontreal https://doi.org/10.1021/acs.est.5b04921 2020-12-27T14:10:09Z 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 m2 E–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. Article in Journal/Newspaper Arctic Bylot Island Climate change Cornwallis Island permafrost polar desert Université de Montréal (UdeM): Papyrus 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 de Montréal (UdeM): Papyrus |
op_collection_id |
ftunivmontreal |
language |
English |
topic |
Photodemethylation Methylmercury Thaw ponds Arctic Organic matter Climate change Biogeochemistry |
spellingShingle |
Photodemethylation Methylmercury Thaw ponds Arctic Organic matter Climate change Biogeochemistry Girard, Catherine Leclerc, Maxime Amyot, Marc Photodemethylation of methylmercury in Eastern Canadian Arctic thaw pond and lake ecosystems |
topic_facet |
Photodemethylation Methylmercury Thaw ponds Arctic Organic matter Climate change Biogeochemistry |
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 m2 E–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. |
author2 |
Université de Montréal. Faculté des arts et des sciences. Département de sciences biologiques |
format |
Article in Journal/Newspaper |
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 |
http://hdl.handle.net/1866/19172 https://doi.org/10.1021/acs.est.5b04921 |
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 Bylot Island Climate change Cornwallis Island permafrost polar desert |
genre_facet |
Arctic Bylot Island Climate change Cornwallis Island permafrost polar desert |
op_relation |
http://hdl.handle.net/1866/19172 doi:10.1021/acs.est.5b04921 |
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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1766313684840218624 |