Long-term development and recent dynamics of High Arctic coastal basins
This study aimed to understand annual and long-term chemical and physical processes that affect the development and state of coastal lakes in the Canadian High Arctic. The first major research project studied the formation of hypersalinity in a seasonally isolated marine basin (SIMB) located near Sh...
Main Author: | |
---|---|
Other Authors: | |
Format: | Thesis |
Language: | English |
Published: |
2010
|
Subjects: | |
Online Access: | http://hdl.handle.net/1974/5687 |
id |
ftcanadathes:oai:collectionscanada.gc.ca:OKQ.1974/5687 |
---|---|
record_format |
openpolar |
spelling |
ftcanadathes:oai:collectionscanada.gc.ca:OKQ.1974/5687 2023-05-15T14:55:22+02:00 Long-term development and recent dynamics of High Arctic coastal basins Dugan, Hilary Queen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.)) 2010-05-24 10:26:59.208 http://hdl.handle.net/1974/5687 en eng Canadian theses http://hdl.handle.net/1974/5687 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. Limnology Hydrology Thesis 2010 ftcanadathes 2013-12-22T00:47:30Z This study aimed to understand annual and long-term chemical and physical processes that affect the development and state of coastal lakes in the Canadian High Arctic. The first major research project studied the formation of hypersalinity in a seasonally isolated marine basin (SIMB) located near Shellabear Point, Melville Island, Northwest Territories (75'N, 113'W). To quantify the role of brine rejection from a seasonal ice pan, an annual ice-formation model was applied, which incorporated stable oxygen isotope fractionation. This model complemented seasonal sampling of ionic and isotopic composition and a full-year recording of physical lacustrine parameters. Additionally, a pilot study using radon-222 as a tracer of groundwater seepage was undertaken to quantify the brine seepage from surrounding permafrost into the hypolimnion of the SIMB. Results indicate that brine rejection from the annual formation of lake ice in a SIMB is the major driver of hypersalinity in this system, and that the current chemical constitution may have formed in less than a decade. This study contributes novel hypotheses on the chemical formation of hypersaline lakes, but also coastal meromictic lakes derived from epishelf lakes during the Holocene. The second investigation focused on the seasonal variability of limnological processes in two coastal freshwater lakes in the Canadian Arctic. East and West Lake are located at the Cape Bounty Arctic Watershed Observatory (CBAWO, 75'N, 109'W), Melville Island. From 2006 to 2009, there have been two central changes in the lake systems: 1) an enhanced ionic loading into both lakes since 2007, and 2) a significant increase in the suspended sediment concentration in the lower 15 m of West Lake in 2009. The elevated ionic concentrations are a result of increased active layer thickening during an unusually warm summer in 2007. The high turbidity in 2009 had a substantial impact on annual mixing of West Lake. The suspended sediment produced a density gradient that prevented river-generated density currents from delivering fresh oxygenated water to the bottom of the lake, and prevented thermal warming. The lack of re-oxygenation and nutrient delivery likely had a substantial impact on the benthic ecosystem in the lake. Thesis (Master, Geography) -- Queen's University, 2010-05-24 10:26:59.208 Thesis Arctic Ice Northwest Territories permafrost Melville Island Theses Canada/Thèses Canada (Library and Archives Canada) Arctic Cape Bounty ENVELOPE(-109.542,-109.542,74.863,74.863) Northwest Territories Shellabear Point ENVELOPE(-113.304,-113.304,74.881,74.881) |
institution |
Open Polar |
collection |
Theses Canada/Thèses Canada (Library and Archives Canada) |
op_collection_id |
ftcanadathes |
language |
English |
topic |
Limnology Hydrology |
spellingShingle |
Limnology Hydrology Dugan, Hilary Long-term development and recent dynamics of High Arctic coastal basins |
topic_facet |
Limnology Hydrology |
description |
This study aimed to understand annual and long-term chemical and physical processes that affect the development and state of coastal lakes in the Canadian High Arctic. The first major research project studied the formation of hypersalinity in a seasonally isolated marine basin (SIMB) located near Shellabear Point, Melville Island, Northwest Territories (75'N, 113'W). To quantify the role of brine rejection from a seasonal ice pan, an annual ice-formation model was applied, which incorporated stable oxygen isotope fractionation. This model complemented seasonal sampling of ionic and isotopic composition and a full-year recording of physical lacustrine parameters. Additionally, a pilot study using radon-222 as a tracer of groundwater seepage was undertaken to quantify the brine seepage from surrounding permafrost into the hypolimnion of the SIMB. Results indicate that brine rejection from the annual formation of lake ice in a SIMB is the major driver of hypersalinity in this system, and that the current chemical constitution may have formed in less than a decade. This study contributes novel hypotheses on the chemical formation of hypersaline lakes, but also coastal meromictic lakes derived from epishelf lakes during the Holocene. The second investigation focused on the seasonal variability of limnological processes in two coastal freshwater lakes in the Canadian Arctic. East and West Lake are located at the Cape Bounty Arctic Watershed Observatory (CBAWO, 75'N, 109'W), Melville Island. From 2006 to 2009, there have been two central changes in the lake systems: 1) an enhanced ionic loading into both lakes since 2007, and 2) a significant increase in the suspended sediment concentration in the lower 15 m of West Lake in 2009. The elevated ionic concentrations are a result of increased active layer thickening during an unusually warm summer in 2007. The high turbidity in 2009 had a substantial impact on annual mixing of West Lake. The suspended sediment produced a density gradient that prevented river-generated density currents from delivering fresh oxygenated water to the bottom of the lake, and prevented thermal warming. The lack of re-oxygenation and nutrient delivery likely had a substantial impact on the benthic ecosystem in the lake. Thesis (Master, Geography) -- Queen's University, 2010-05-24 10:26:59.208 |
author2 |
Queen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.)) |
format |
Thesis |
author |
Dugan, Hilary |
author_facet |
Dugan, Hilary |
author_sort |
Dugan, Hilary |
title |
Long-term development and recent dynamics of High Arctic coastal basins |
title_short |
Long-term development and recent dynamics of High Arctic coastal basins |
title_full |
Long-term development and recent dynamics of High Arctic coastal basins |
title_fullStr |
Long-term development and recent dynamics of High Arctic coastal basins |
title_full_unstemmed |
Long-term development and recent dynamics of High Arctic coastal basins |
title_sort |
long-term development and recent dynamics of high arctic coastal basins |
publishDate |
2010 |
url |
http://hdl.handle.net/1974/5687 |
long_lat |
ENVELOPE(-109.542,-109.542,74.863,74.863) ENVELOPE(-113.304,-113.304,74.881,74.881) |
geographic |
Arctic Cape Bounty Northwest Territories Shellabear Point |
geographic_facet |
Arctic Cape Bounty Northwest Territories Shellabear Point |
genre |
Arctic Ice Northwest Territories permafrost Melville Island |
genre_facet |
Arctic Ice Northwest Territories permafrost Melville Island |
op_relation |
Canadian theses http://hdl.handle.net/1974/5687 |
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_ |
1766327164869804032 |