A paleolimnological assessment of recent environmental changes in lakes of the western Canadian Arctic
Thesis (Ph.D, Biology) -- Queen's University, 2013-04-17 09:30:14.671 The freshwater ecosystems in the western Canadian Arctic are threatened by multiple and interacting stressors, as high-latitude regions are undergoing rapid change resulting from climate warming and other human-related activi...
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ftqueensuniv:oai:qspace.library.queensu.ca:1974/7878 2023-05-15T14:55:22+02:00 A paleolimnological assessment of recent environmental changes in lakes of the western Canadian Arctic Thienpont, Joshua Smol, John P. Biology 2013-04-17 09:30:14.671 http://hdl.handle.net/1974/7878 eng eng Canadian theses http://hdl.handle.net/1974/7878 This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. permafrost Arctic lakes freshwater paleolimnology climate change ecology diatom thesis 2013 ftqueensuniv 2020-12-29T09:06:39Z Thesis (Ph.D, Biology) -- Queen's University, 2013-04-17 09:30:14.671 The freshwater ecosystems in the western Canadian Arctic are threatened by multiple and interacting stressors, as high-latitude regions are undergoing rapid change resulting from climate warming and other human-related activities. However, due to the paucity or absence of monitoring data, little is known about long-term changes in lake ecosystems. This thesis addresses this knowledge gap by using paleolimnological techniques to assess the responses of freshwater ecosystems in the Mackenzie Delta region to three major stressors predicted to become increasingly important, namely impacts from accelerated permafrost thaw, marine storm surges, and hydrocarbon exploration. Using a paired-lake design, six reference lakes were compared to six lakes impacted by retrogressive thaw slumps, an important form of thermokarst in this region. While all of the study lakes have undergone ecologically significant biological changes over the last ~200 years as a result of warming, lakes impacted by thaw slumps have changed more due to the cumulative effects of warming and heightened permafrost thaw. In addition to warming, the outer Mackenzie Delta is a low-lying landscape that is susceptible to inundation by marine storm surges from the Beaufort Sea. A large storm event in 1999 flooded >10,000 hectares of the outer delta. My paleolimnological data show that this marine intrusion resulted in diatom assemblage changes in flooded lakes on a landscape-scale that were unprecedented in the recent past, suggesting recent warming, and associated sea-ice decreases, are making this region more susceptible to storm-surge damage. Finally, lakes impacted by sumps used to dispose of the drilling by-products of hydrocarbon exploration exhibit distinct water chemistry, and are particularly elevated in potassium and chloride, which form a major component of some drilling fluids. Related to this, a discernible change in cladoceran assemblages coeval with the time of sump construction suggest that sump failure has resulted in biological changes in affected lakes. Collectively, this research shows that the ecosystems of the western Canadian Arctic are under threat from multiple stressors that have resulted in changes to the chemistry and biology of the freshwater resources of this region. PhD Thesis Arctic Beaufort Sea Climate change Ice Mackenzie Delta permafrost Sea ice Thermokarst Queen's University, Ontario: QSpace Arctic Mackenzie Delta ENVELOPE(-136.672,-136.672,68.833,68.833) |
institution |
Open Polar |
collection |
Queen's University, Ontario: QSpace |
op_collection_id |
ftqueensuniv |
language |
English |
topic |
permafrost Arctic lakes freshwater paleolimnology climate change ecology diatom |
spellingShingle |
permafrost Arctic lakes freshwater paleolimnology climate change ecology diatom Thienpont, Joshua A paleolimnological assessment of recent environmental changes in lakes of the western Canadian Arctic |
topic_facet |
permafrost Arctic lakes freshwater paleolimnology climate change ecology diatom |
description |
Thesis (Ph.D, Biology) -- Queen's University, 2013-04-17 09:30:14.671 The freshwater ecosystems in the western Canadian Arctic are threatened by multiple and interacting stressors, as high-latitude regions are undergoing rapid change resulting from climate warming and other human-related activities. However, due to the paucity or absence of monitoring data, little is known about long-term changes in lake ecosystems. This thesis addresses this knowledge gap by using paleolimnological techniques to assess the responses of freshwater ecosystems in the Mackenzie Delta region to three major stressors predicted to become increasingly important, namely impacts from accelerated permafrost thaw, marine storm surges, and hydrocarbon exploration. Using a paired-lake design, six reference lakes were compared to six lakes impacted by retrogressive thaw slumps, an important form of thermokarst in this region. While all of the study lakes have undergone ecologically significant biological changes over the last ~200 years as a result of warming, lakes impacted by thaw slumps have changed more due to the cumulative effects of warming and heightened permafrost thaw. In addition to warming, the outer Mackenzie Delta is a low-lying landscape that is susceptible to inundation by marine storm surges from the Beaufort Sea. A large storm event in 1999 flooded >10,000 hectares of the outer delta. My paleolimnological data show that this marine intrusion resulted in diatom assemblage changes in flooded lakes on a landscape-scale that were unprecedented in the recent past, suggesting recent warming, and associated sea-ice decreases, are making this region more susceptible to storm-surge damage. Finally, lakes impacted by sumps used to dispose of the drilling by-products of hydrocarbon exploration exhibit distinct water chemistry, and are particularly elevated in potassium and chloride, which form a major component of some drilling fluids. Related to this, a discernible change in cladoceran assemblages coeval with the time of sump construction suggest that sump failure has resulted in biological changes in affected lakes. Collectively, this research shows that the ecosystems of the western Canadian Arctic are under threat from multiple stressors that have resulted in changes to the chemistry and biology of the freshwater resources of this region. PhD |
author2 |
Smol, John P. Biology |
format |
Thesis |
author |
Thienpont, Joshua |
author_facet |
Thienpont, Joshua |
author_sort |
Thienpont, Joshua |
title |
A paleolimnological assessment of recent environmental changes in lakes of the western Canadian Arctic |
title_short |
A paleolimnological assessment of recent environmental changes in lakes of the western Canadian Arctic |
title_full |
A paleolimnological assessment of recent environmental changes in lakes of the western Canadian Arctic |
title_fullStr |
A paleolimnological assessment of recent environmental changes in lakes of the western Canadian Arctic |
title_full_unstemmed |
A paleolimnological assessment of recent environmental changes in lakes of the western Canadian Arctic |
title_sort |
paleolimnological assessment of recent environmental changes in lakes of the western canadian arctic |
publishDate |
2013 |
url |
http://hdl.handle.net/1974/7878 |
long_lat |
ENVELOPE(-136.672,-136.672,68.833,68.833) |
geographic |
Arctic Mackenzie Delta |
geographic_facet |
Arctic Mackenzie Delta |
genre |
Arctic Beaufort Sea Climate change Ice Mackenzie Delta permafrost Sea ice Thermokarst |
genre_facet |
Arctic Beaufort Sea Climate change Ice Mackenzie Delta permafrost Sea ice Thermokarst |
op_relation |
Canadian theses http://hdl.handle.net/1974/7878 |
op_rights |
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. |
_version_ |
1766327169429012480 |