Exceptional summer warming leads to contrasting outcomes for methane cycling in small Arctic lakes of Greenland
In thermally stratified lakes, the greatest annual methane emissions typically occur during thermal overturn events. In July of 2012, Greenland experienced significant warming that resulted in substantial melting of the Greenland Ice Sheet and enhanced runoff events. This unusual climate phenomenon...
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ftdoajarticles:oai:doaj.org/article:95b7731f05554fde8381eb3a21321119 2023-05-15T15:15:48+02:00 Exceptional summer warming leads to contrasting outcomes for methane cycling in small Arctic lakes of Greenland S. B. Cadieux J. R. White L. M. Pratt 2017-02-01T00:00:00Z https://doi.org/10.5194/bg-14-559-2017 https://doaj.org/article/95b7731f05554fde8381eb3a21321119 EN eng Copernicus Publications http://www.biogeosciences.net/14/559/2017/bg-14-559-2017.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-14-559-2017 https://doaj.org/article/95b7731f05554fde8381eb3a21321119 Biogeosciences, Vol 14, Iss 3, Pp 559-574 (2017) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2017 ftdoajarticles https://doi.org/10.5194/bg-14-559-2017 2022-12-31T13:42:50Z In thermally stratified lakes, the greatest annual methane emissions typically occur during thermal overturn events. In July of 2012, Greenland experienced significant warming that resulted in substantial melting of the Greenland Ice Sheet and enhanced runoff events. This unusual climate phenomenon provided an opportunity to examine the effects of short-term natural heating on lake thermal structure and methane dynamics and compare these observations with those from the following year, when temperatures were normal. Here, we focus on methane concentrations within the water column of five adjacent small lakes on the ice-free margin of southwestern Greenland under open-water and ice-covered conditions from 2012–2014. Enhanced warming of the epilimnion in the lakes under open-water conditions in 2012 led to strong thermal stability and the development of anoxic hypolimnia in each of the lakes. As a result, during open-water conditions, mean dissolved methane concentrations in the water column were significantly ( p < 0.0001) greater in 2012 than in 2013. In all of the lakes, mean methane concentrations under ice-covered conditions were significantly ( p < 0.0001) greater than under open-water conditions, suggesting spring overturn is currently the largest annual methane flux to the atmosphere. As the climate continues to warm, shorter ice cover durations are expected, which may reduce the winter inventory of methane and lead to a decrease in total methane flux during ice melt. Under open-water conditions, greater heat income and warming of lake surface waters will lead to increased thermal stratification and hypolimnetic anoxia, which will consequently result in increased water column inventories of methane. This stored methane will be susceptible to emissions during fall overturn, which may result in a shift in greatest annual efflux of methane from spring melt to fall overturn. The results of this study suggest that interannual variation in ground-level air temperatures may be the primary driver of changes ... Article in Journal/Newspaper Arctic Greenland Ice Sheet Directory of Open Access Journals: DOAJ Articles Arctic Greenland Biogeosciences 14 3 559 574 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
spellingShingle |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 S. B. Cadieux J. R. White L. M. Pratt Exceptional summer warming leads to contrasting outcomes for methane cycling in small Arctic lakes of Greenland |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
In thermally stratified lakes, the greatest annual methane emissions typically occur during thermal overturn events. In July of 2012, Greenland experienced significant warming that resulted in substantial melting of the Greenland Ice Sheet and enhanced runoff events. This unusual climate phenomenon provided an opportunity to examine the effects of short-term natural heating on lake thermal structure and methane dynamics and compare these observations with those from the following year, when temperatures were normal. Here, we focus on methane concentrations within the water column of five adjacent small lakes on the ice-free margin of southwestern Greenland under open-water and ice-covered conditions from 2012–2014. Enhanced warming of the epilimnion in the lakes under open-water conditions in 2012 led to strong thermal stability and the development of anoxic hypolimnia in each of the lakes. As a result, during open-water conditions, mean dissolved methane concentrations in the water column were significantly ( p < 0.0001) greater in 2012 than in 2013. In all of the lakes, mean methane concentrations under ice-covered conditions were significantly ( p < 0.0001) greater than under open-water conditions, suggesting spring overturn is currently the largest annual methane flux to the atmosphere. As the climate continues to warm, shorter ice cover durations are expected, which may reduce the winter inventory of methane and lead to a decrease in total methane flux during ice melt. Under open-water conditions, greater heat income and warming of lake surface waters will lead to increased thermal stratification and hypolimnetic anoxia, which will consequently result in increased water column inventories of methane. This stored methane will be susceptible to emissions during fall overturn, which may result in a shift in greatest annual efflux of methane from spring melt to fall overturn. The results of this study suggest that interannual variation in ground-level air temperatures may be the primary driver of changes ... |
format |
Article in Journal/Newspaper |
author |
S. B. Cadieux J. R. White L. M. Pratt |
author_facet |
S. B. Cadieux J. R. White L. M. Pratt |
author_sort |
S. B. Cadieux |
title |
Exceptional summer warming leads to contrasting outcomes for methane cycling in small Arctic lakes of Greenland |
title_short |
Exceptional summer warming leads to contrasting outcomes for methane cycling in small Arctic lakes of Greenland |
title_full |
Exceptional summer warming leads to contrasting outcomes for methane cycling in small Arctic lakes of Greenland |
title_fullStr |
Exceptional summer warming leads to contrasting outcomes for methane cycling in small Arctic lakes of Greenland |
title_full_unstemmed |
Exceptional summer warming leads to contrasting outcomes for methane cycling in small Arctic lakes of Greenland |
title_sort |
exceptional summer warming leads to contrasting outcomes for methane cycling in small arctic lakes of greenland |
publisher |
Copernicus Publications |
publishDate |
2017 |
url |
https://doi.org/10.5194/bg-14-559-2017 https://doaj.org/article/95b7731f05554fde8381eb3a21321119 |
geographic |
Arctic Greenland |
geographic_facet |
Arctic Greenland |
genre |
Arctic Greenland Ice Sheet |
genre_facet |
Arctic Greenland Ice Sheet |
op_source |
Biogeosciences, Vol 14, Iss 3, Pp 559-574 (2017) |
op_relation |
http://www.biogeosciences.net/14/559/2017/bg-14-559-2017.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-14-559-2017 https://doaj.org/article/95b7731f05554fde8381eb3a21321119 |
op_doi |
https://doi.org/10.5194/bg-14-559-2017 |
container_title |
Biogeosciences |
container_volume |
14 |
container_issue |
3 |
container_start_page |
559 |
op_container_end_page |
574 |
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1766346140809166848 |