IMPACT OF ACTIVE LAYER DETACHMENTS ON SEASONAL DYNAMICS OF NITROGEN EXPORT IN HIGH ARCTIC WATERSHEDS
This study examined the impact of active layer detachments (ALDs) on seasonal dissolved nitrogen (N) export from continuous permafrost headwater catchments at the Cape Bounty Arctic Watershed Observatory (CBAWO), Melville Island, Nunavut. Runoff samples collected throughout the summer of 2012 from a...
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ftcanadathes:oai:collectionscanada.gc.ca:OKQ.1974/12208 2023-05-15T14:55:20+02:00 IMPACT OF ACTIVE LAYER DETACHMENTS ON SEASONAL DYNAMICS OF NITROGEN EXPORT IN HIGH ARCTIC WATERSHEDS Louiseize, NICOLE Queen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.)) 2014-05-27 10:30:38.874 http://hdl.handle.net/1974/12208 en eng Canadian theses http://hdl.handle.net/1974/12208 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. nitrate active layer detachment nitrification high arctic Thesis 2014 ftcanadathes 2014-06-07T23:45:34Z This study examined the impact of active layer detachments (ALDs) on seasonal dissolved nitrogen (N) export from continuous permafrost headwater catchments at the Cape Bounty Arctic Watershed Observatory (CBAWO), Melville Island, Nunavut. Runoff samples collected throughout the summer of 2012 from an undisturbed catchment (Goose; GS) and from one that was disturbed by ALDs (Ptarmigan; PT) were analyzed for dissolved inorganic ions and species of total dissolved N (TDN), including dissolved organic N (DON) and dissolved inorganic N (DIN; ammonium (NH4+), nitrite (NO2-), and nitrate (NO3-)). Rainfall samples were also collected for dissolved ions analyses. Select runoff and rainfall samples were analyzed for stable isotopes of nitrogen and oxygen in NO3- (δ15N-NO3- and δ18O-NO3-, respectively) to determine its origin streamwater. Data from 2012 were compared to predisturbance data to assess the long-term effects of ALDs on N export. ALDs increased the proportion of DIN/TDN in PT from 4% (predisturbance) to 37% in 2012. The increase in DIN/TDN in PT largely resulted from significantly higher NO3- in runoff. Values of δ18O and δ15N-NO3- as well as correlations between NO3- and major ions indicated that the higher NO3- in PT was due to the exposure of mineral soils in ALDs, which likely reduced NO3- sinks (e.g. plant uptake) and increased inputs of nitrified-NO3-. Values of δ18O-NO3- during initial runoff showed that NO3- supplied from the snowpack overwhelmed NO3- sinks in PT, leading to a twelve-fold higher peak NO3- concentration relative to GS. Low δ18O-NO3- values in runoff during stormflow indicated that inputs of DIN from rainfall (1545 ± 148 and 1838 ± 174 g N-DIN to GS and PT, respectively) supplied less than 30% of the NO3- in both streams, and that exceptionally high NO3- concentrations in PT resulted from flushing of mineralized-NO3- from the mineral soils. Seasonal DIN flux was 95% higher in PT relative to GS, because NO3- export from PT was 27 times that of GS. This is the first study to show that ALDs can have persistent impacts on DIN export from High Arctic watersheds, and that this results from enhanced export of mineralized-NO3-. Thesis (Master, Geography) -- Queen's University, 2014-05-27 10:30:38.874 Thesis Arctic Nunavut permafrost Melville Island Theses Canada/Thèses Canada (Library and Archives Canada) Arctic Cape Bounty ENVELOPE(-109.542,-109.542,74.863,74.863) Nunavut |
institution |
Open Polar |
collection |
Theses Canada/Thèses Canada (Library and Archives Canada) |
op_collection_id |
ftcanadathes |
language |
English |
topic |
nitrate active layer detachment nitrification high arctic |
spellingShingle |
nitrate active layer detachment nitrification high arctic Louiseize, NICOLE IMPACT OF ACTIVE LAYER DETACHMENTS ON SEASONAL DYNAMICS OF NITROGEN EXPORT IN HIGH ARCTIC WATERSHEDS |
topic_facet |
nitrate active layer detachment nitrification high arctic |
description |
This study examined the impact of active layer detachments (ALDs) on seasonal dissolved nitrogen (N) export from continuous permafrost headwater catchments at the Cape Bounty Arctic Watershed Observatory (CBAWO), Melville Island, Nunavut. Runoff samples collected throughout the summer of 2012 from an undisturbed catchment (Goose; GS) and from one that was disturbed by ALDs (Ptarmigan; PT) were analyzed for dissolved inorganic ions and species of total dissolved N (TDN), including dissolved organic N (DON) and dissolved inorganic N (DIN; ammonium (NH4+), nitrite (NO2-), and nitrate (NO3-)). Rainfall samples were also collected for dissolved ions analyses. Select runoff and rainfall samples were analyzed for stable isotopes of nitrogen and oxygen in NO3- (δ15N-NO3- and δ18O-NO3-, respectively) to determine its origin streamwater. Data from 2012 were compared to predisturbance data to assess the long-term effects of ALDs on N export. ALDs increased the proportion of DIN/TDN in PT from 4% (predisturbance) to 37% in 2012. The increase in DIN/TDN in PT largely resulted from significantly higher NO3- in runoff. Values of δ18O and δ15N-NO3- as well as correlations between NO3- and major ions indicated that the higher NO3- in PT was due to the exposure of mineral soils in ALDs, which likely reduced NO3- sinks (e.g. plant uptake) and increased inputs of nitrified-NO3-. Values of δ18O-NO3- during initial runoff showed that NO3- supplied from the snowpack overwhelmed NO3- sinks in PT, leading to a twelve-fold higher peak NO3- concentration relative to GS. Low δ18O-NO3- values in runoff during stormflow indicated that inputs of DIN from rainfall (1545 ± 148 and 1838 ± 174 g N-DIN to GS and PT, respectively) supplied less than 30% of the NO3- in both streams, and that exceptionally high NO3- concentrations in PT resulted from flushing of mineralized-NO3- from the mineral soils. Seasonal DIN flux was 95% higher in PT relative to GS, because NO3- export from PT was 27 times that of GS. This is the first study to show that ALDs can have persistent impacts on DIN export from High Arctic watersheds, and that this results from enhanced export of mineralized-NO3-. Thesis (Master, Geography) -- Queen's University, 2014-05-27 10:30:38.874 |
author2 |
Queen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.)) |
format |
Thesis |
author |
Louiseize, NICOLE |
author_facet |
Louiseize, NICOLE |
author_sort |
Louiseize, NICOLE |
title |
IMPACT OF ACTIVE LAYER DETACHMENTS ON SEASONAL DYNAMICS OF NITROGEN EXPORT IN HIGH ARCTIC WATERSHEDS |
title_short |
IMPACT OF ACTIVE LAYER DETACHMENTS ON SEASONAL DYNAMICS OF NITROGEN EXPORT IN HIGH ARCTIC WATERSHEDS |
title_full |
IMPACT OF ACTIVE LAYER DETACHMENTS ON SEASONAL DYNAMICS OF NITROGEN EXPORT IN HIGH ARCTIC WATERSHEDS |
title_fullStr |
IMPACT OF ACTIVE LAYER DETACHMENTS ON SEASONAL DYNAMICS OF NITROGEN EXPORT IN HIGH ARCTIC WATERSHEDS |
title_full_unstemmed |
IMPACT OF ACTIVE LAYER DETACHMENTS ON SEASONAL DYNAMICS OF NITROGEN EXPORT IN HIGH ARCTIC WATERSHEDS |
title_sort |
impact of active layer detachments on seasonal dynamics of nitrogen export in high arctic watersheds |
publishDate |
2014 |
url |
http://hdl.handle.net/1974/12208 |
long_lat |
ENVELOPE(-109.542,-109.542,74.863,74.863) |
geographic |
Arctic Cape Bounty Nunavut |
geographic_facet |
Arctic Cape Bounty Nunavut |
genre |
Arctic Nunavut permafrost Melville Island |
genre_facet |
Arctic Nunavut permafrost Melville Island |
op_relation |
Canadian theses http://hdl.handle.net/1974/12208 |
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_ |
1766327136913719296 |