Diatom ecological response to deposition of the 833-850 CE White River Ash (east lobe) ashfall in a small subarctic Canadian lake
A <5 mm thick volcanic ashfall layer associated with the White River Ash (east lobe [WRAe]) originating from the eruption of Mount Churchill, Alaska (833-850 CE; 1,117–1,100 cal BP) was observed in two freeze cores obtained from Pocket Lake (62.5090°N, −114.3719°W), a small subarctic lake located...
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crpeerj:10.7717/peerj.6269 2024-06-02T08:12:20+00:00 Diatom ecological response to deposition of the 833-850 CE White River Ash (east lobe) ashfall in a small subarctic Canadian lake Hutchinson, Scott J. Hamilton, Paul B. Patterson, R. Timothy Galloway, Jennifer M. Nasser, Nawaf A. Spence, Christopher Falck, Hendrik Cumulative Impact and Monitoring Program Grant Northwest Territories Geological Survey Geological Survey of Canada North Slave Métis Alliance NRCan 2019 http://dx.doi.org/10.7717/peerj.6269 https://peerj.com/articles/6269.pdf https://peerj.com/articles/6269.xml https://peerj.com/articles/6269.html en eng PeerJ http://creativecommons.org/licenses/by/4.0/ PeerJ volume 7, page e6269 ISSN 2167-8359 journal-article 2019 crpeerj https://doi.org/10.7717/peerj.6269 2024-05-07T14:13:48Z A <5 mm thick volcanic ashfall layer associated with the White River Ash (east lobe [WRAe]) originating from the eruption of Mount Churchill, Alaska (833-850 CE; 1,117–1,100 cal BP) was observed in two freeze cores obtained from Pocket Lake (62.5090°N, −114.3719°W), a small subarctic lake located within the city limits of Yellowknife, Northwest Territories, Canada. Here we analyze changes in diatom assemblages to assess impact of tephra deposition on the aquatic biota of a subarctic lake. In a well-dated core constrained by 8 radiocarbon dates, diatom counts were carried out at 1-mm intervals through an interval spanning 1 cm above and below the tephra layer with each 1 mm sub-sample represented about 2 years of deposition. Non-metric Multidimensional Scaling (NMDS) and Stratigraphically Constrained Incremental Sum of Squares (CONISS) analyses were carried out and three distinct diatom assemblages were identified throughout the interval. The lowermost “Pre-WRAe Assemblage (Pre-WRAeA)” was indicative of slightly acidic and eutrophic lacustrine conditions. Winter deposition of the tephra layer drove a subsequent diatom flora shift to the “WRAe Assemblage (WRAeA)” the following spring. The WRAeA contained elevated abundances of taxa associated with oligotrophic, nutrient depleted and slightly more alkaline lake waters. These changes were only apparent in samples within the WRAe containing interval indicating that they were short lived and only sustained for a single year of deposition. Immediately above the WRAe horizon, a third, “Post-WRAe Assemblage (Post-WRAeA)” was observed. This assemblage was initially similar to that of the Pre-WRAeA but gradually became more distinct upwards, likely due to climatic patterns independent of the WRAe event. These results suggest that lacustrine environments are sensitive to perturbations such as deposition of ash fall, but that ecological communities in subarctic systems can also have high resilience and can recover rapidly. If subsampling of the freeze cores was carried ... Article in Journal/Newspaper Northwest Territories Subarctic Yellowknife Alaska PeerJ Publishing Canada Northwest Territories Yellowknife PeerJ 7 e6269 |
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Open Polar |
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PeerJ Publishing |
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language |
English |
description |
A <5 mm thick volcanic ashfall layer associated with the White River Ash (east lobe [WRAe]) originating from the eruption of Mount Churchill, Alaska (833-850 CE; 1,117–1,100 cal BP) was observed in two freeze cores obtained from Pocket Lake (62.5090°N, −114.3719°W), a small subarctic lake located within the city limits of Yellowknife, Northwest Territories, Canada. Here we analyze changes in diatom assemblages to assess impact of tephra deposition on the aquatic biota of a subarctic lake. In a well-dated core constrained by 8 radiocarbon dates, diatom counts were carried out at 1-mm intervals through an interval spanning 1 cm above and below the tephra layer with each 1 mm sub-sample represented about 2 years of deposition. Non-metric Multidimensional Scaling (NMDS) and Stratigraphically Constrained Incremental Sum of Squares (CONISS) analyses were carried out and three distinct diatom assemblages were identified throughout the interval. The lowermost “Pre-WRAe Assemblage (Pre-WRAeA)” was indicative of slightly acidic and eutrophic lacustrine conditions. Winter deposition of the tephra layer drove a subsequent diatom flora shift to the “WRAe Assemblage (WRAeA)” the following spring. The WRAeA contained elevated abundances of taxa associated with oligotrophic, nutrient depleted and slightly more alkaline lake waters. These changes were only apparent in samples within the WRAe containing interval indicating that they were short lived and only sustained for a single year of deposition. Immediately above the WRAe horizon, a third, “Post-WRAe Assemblage (Post-WRAeA)” was observed. This assemblage was initially similar to that of the Pre-WRAeA but gradually became more distinct upwards, likely due to climatic patterns independent of the WRAe event. These results suggest that lacustrine environments are sensitive to perturbations such as deposition of ash fall, but that ecological communities in subarctic systems can also have high resilience and can recover rapidly. If subsampling of the freeze cores was carried ... |
author2 |
Cumulative Impact and Monitoring Program Grant Northwest Territories Geological Survey Geological Survey of Canada North Slave Métis Alliance NRCan |
format |
Article in Journal/Newspaper |
author |
Hutchinson, Scott J. Hamilton, Paul B. Patterson, R. Timothy Galloway, Jennifer M. Nasser, Nawaf A. Spence, Christopher Falck, Hendrik |
spellingShingle |
Hutchinson, Scott J. Hamilton, Paul B. Patterson, R. Timothy Galloway, Jennifer M. Nasser, Nawaf A. Spence, Christopher Falck, Hendrik Diatom ecological response to deposition of the 833-850 CE White River Ash (east lobe) ashfall in a small subarctic Canadian lake |
author_facet |
Hutchinson, Scott J. Hamilton, Paul B. Patterson, R. Timothy Galloway, Jennifer M. Nasser, Nawaf A. Spence, Christopher Falck, Hendrik |
author_sort |
Hutchinson, Scott J. |
title |
Diatom ecological response to deposition of the 833-850 CE White River Ash (east lobe) ashfall in a small subarctic Canadian lake |
title_short |
Diatom ecological response to deposition of the 833-850 CE White River Ash (east lobe) ashfall in a small subarctic Canadian lake |
title_full |
Diatom ecological response to deposition of the 833-850 CE White River Ash (east lobe) ashfall in a small subarctic Canadian lake |
title_fullStr |
Diatom ecological response to deposition of the 833-850 CE White River Ash (east lobe) ashfall in a small subarctic Canadian lake |
title_full_unstemmed |
Diatom ecological response to deposition of the 833-850 CE White River Ash (east lobe) ashfall in a small subarctic Canadian lake |
title_sort |
diatom ecological response to deposition of the 833-850 ce white river ash (east lobe) ashfall in a small subarctic canadian lake |
publisher |
PeerJ |
publishDate |
2019 |
url |
http://dx.doi.org/10.7717/peerj.6269 https://peerj.com/articles/6269.pdf https://peerj.com/articles/6269.xml https://peerj.com/articles/6269.html |
geographic |
Canada Northwest Territories Yellowknife |
geographic_facet |
Canada Northwest Territories Yellowknife |
genre |
Northwest Territories Subarctic Yellowknife Alaska |
genre_facet |
Northwest Territories Subarctic Yellowknife Alaska |
op_source |
PeerJ volume 7, page e6269 ISSN 2167-8359 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.7717/peerj.6269 |
container_title |
PeerJ |
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7 |
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e6269 |
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1800758726600163328 |