Role of River Runoff and Sea Ice Brine Rejection in Controlling Stratification Throughout Winter in Southeast Hudson Bay
Abstract The Hudson Bay system is undergoing climate-driven changes in sea ice and freshwater inflow and has seen an increase in winter river inflow since the 1960s due in part to flow regulation for hydropower production. Southeast Hudson Bay and adjacent James Bay are at the forefront of these cha...
Published in: | Estuaries and Coasts |
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Main Authors: | , , , , , , , |
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Format: | Article in Journal/Newspaper |
Language: | English |
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Springer Science and Business Media LLC
2020
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Online Access: | http://dx.doi.org/10.1007/s12237-020-00698-0 http://link.springer.com/content/pdf/10.1007/s12237-020-00698-0.pdf http://link.springer.com/article/10.1007/s12237-020-00698-0/fulltext.html |
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crspringernat:10.1007/s12237-020-00698-0 |
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Open Polar |
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Springer Nature (via Crossref) |
op_collection_id |
crspringernat |
language |
English |
topic |
Ecology Aquatic Science Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Ecology Aquatic Science Ecology, Evolution, Behavior and Systematics Eastwood, Rosemary Ann Macdonald, R. W. Ehn, J. K. Heath, J. Arragutainaq, L. Myers, P. G. Barber, D. G. Kuzyk, Z. A. Role of River Runoff and Sea Ice Brine Rejection in Controlling Stratification Throughout Winter in Southeast Hudson Bay |
topic_facet |
Ecology Aquatic Science Ecology, Evolution, Behavior and Systematics |
description |
Abstract The Hudson Bay system is undergoing climate-driven changes in sea ice and freshwater inflow and has seen an increase in winter river inflow since the 1960s due in part to flow regulation for hydropower production. Southeast Hudson Bay and adjacent James Bay are at the forefront of these changes, with more than 1-month shortening of the season of sea ice cover as defined using satellite data, increases in winter inflow from the regulated La Grande River complex, and changes in coastal ice and polynya behavior described by Belcher Islands’ Inuit. In summer, there is a fresh coastal domain in southeast Hudson Bay fueled by river runoff and sea ice melt. To investigate winter oceanographic conditions and potential interactions between runoff and ice melt or brine in southeast Hudson Bay, we initiated the first winter study of the shallow waters surrounding the Belchers, collecting conductivity-temperature-depth (CTD) profiles and conductivity-temperature (CT) time series using under-ice moorings, and collecting water samples and ice cores during four campaigns between January 2014 and March 2015. Tandem measurements of salinity and δ 18 O were made for the water and ice samples to discriminate between freshwater sources (river runoff and sea ice melt). We find that southeast Hudson Bay, and particularly the nearshore domain southeast of the Belchers, is distinguished in winter by the presence of river water and strong surface stratification, which runs counter to expectations for a system in which local freshwater remains frozen on land until spring freshet (May–June) and sea ice growth is adding brine to surface waters. The amount of river water around the Belcher Islands increased significantly from fall through to late winter according to δ 18 O records of ice. The accumulation of river water in surface waters during the winter is directly associated with an accumulation of brine, which considerably exceeds the capacity of local ice formation to produce brine. We therefore infer that brine is advected into the study area together with river water, and that interplay between these properties establishes and maintains the level of surface stratification throughout winter. With reference to a NEMO ocean model simulation of winter circulation in the study area, we propose a conceptual model in which winter river inflow into James Bay drives the northward transport of both river water and brine captured near the surface, with reductions in brine-driven deep convection in the area’s flaw leads. While past changes in winter oceanographic conditions and sea ice cannot be reconstructed from the few available scientific data, the presence of significant runoff in winter in southeast Hudson Bay implies heightened sensitivity to delayed freeze-up under a warmer climate, which will have the effect of reducing brine early in the winter, also promoting increased stratification and river plume transport. |
author2 |
ArcticNet Network of Centres of Excellence |
format |
Article in Journal/Newspaper |
author |
Eastwood, Rosemary Ann Macdonald, R. W. Ehn, J. K. Heath, J. Arragutainaq, L. Myers, P. G. Barber, D. G. Kuzyk, Z. A. |
author_facet |
Eastwood, Rosemary Ann Macdonald, R. W. Ehn, J. K. Heath, J. Arragutainaq, L. Myers, P. G. Barber, D. G. Kuzyk, Z. A. |
author_sort |
Eastwood, Rosemary Ann |
title |
Role of River Runoff and Sea Ice Brine Rejection in Controlling Stratification Throughout Winter in Southeast Hudson Bay |
title_short |
Role of River Runoff and Sea Ice Brine Rejection in Controlling Stratification Throughout Winter in Southeast Hudson Bay |
title_full |
Role of River Runoff and Sea Ice Brine Rejection in Controlling Stratification Throughout Winter in Southeast Hudson Bay |
title_fullStr |
Role of River Runoff and Sea Ice Brine Rejection in Controlling Stratification Throughout Winter in Southeast Hudson Bay |
title_full_unstemmed |
Role of River Runoff and Sea Ice Brine Rejection in Controlling Stratification Throughout Winter in Southeast Hudson Bay |
title_sort |
role of river runoff and sea ice brine rejection in controlling stratification throughout winter in southeast hudson bay |
publisher |
Springer Science and Business Media LLC |
publishDate |
2020 |
url |
http://dx.doi.org/10.1007/s12237-020-00698-0 http://link.springer.com/content/pdf/10.1007/s12237-020-00698-0.pdf http://link.springer.com/article/10.1007/s12237-020-00698-0/fulltext.html |
long_lat |
ENVELOPE(-94.172,-94.172,57.936,57.936) ENVELOPE(-79.250,-79.250,56.184,56.184) ENVELOPE(-113.003,-113.003,64.501,64.501) |
geographic |
Belcher Belcher Islands Hudson Hudson Bay Winter River |
geographic_facet |
Belcher Belcher Islands Hudson Hudson Bay Winter River |
genre |
Belcher Islands Hudson Bay inuit La Grande River Sea ice James Bay |
genre_facet |
Belcher Islands Hudson Bay inuit La Grande River Sea ice James Bay |
op_source |
Estuaries and Coasts volume 43, issue 4, page 756-786 ISSN 1559-2723 1559-2731 |
op_rights |
https://creativecommons.org/licenses/by/4.0 https://creativecommons.org/licenses/by/4.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1007/s12237-020-00698-0 |
container_title |
Estuaries and Coasts |
container_volume |
43 |
container_issue |
4 |
container_start_page |
756 |
op_container_end_page |
786 |
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1766374145509031936 |
spelling |
crspringernat:10.1007/s12237-020-00698-0 2023-05-15T15:41:14+02:00 Role of River Runoff and Sea Ice Brine Rejection in Controlling Stratification Throughout Winter in Southeast Hudson Bay Eastwood, Rosemary Ann Macdonald, R. W. Ehn, J. K. Heath, J. Arragutainaq, L. Myers, P. G. Barber, D. G. Kuzyk, Z. A. ArcticNet Network of Centres of Excellence 2020 http://dx.doi.org/10.1007/s12237-020-00698-0 http://link.springer.com/content/pdf/10.1007/s12237-020-00698-0.pdf http://link.springer.com/article/10.1007/s12237-020-00698-0/fulltext.html en eng Springer Science and Business Media LLC https://creativecommons.org/licenses/by/4.0 https://creativecommons.org/licenses/by/4.0 CC-BY Estuaries and Coasts volume 43, issue 4, page 756-786 ISSN 1559-2723 1559-2731 Ecology Aquatic Science Ecology, Evolution, Behavior and Systematics journal-article 2020 crspringernat https://doi.org/10.1007/s12237-020-00698-0 2022-01-04T16:37:13Z Abstract The Hudson Bay system is undergoing climate-driven changes in sea ice and freshwater inflow and has seen an increase in winter river inflow since the 1960s due in part to flow regulation for hydropower production. Southeast Hudson Bay and adjacent James Bay are at the forefront of these changes, with more than 1-month shortening of the season of sea ice cover as defined using satellite data, increases in winter inflow from the regulated La Grande River complex, and changes in coastal ice and polynya behavior described by Belcher Islands’ Inuit. In summer, there is a fresh coastal domain in southeast Hudson Bay fueled by river runoff and sea ice melt. To investigate winter oceanographic conditions and potential interactions between runoff and ice melt or brine in southeast Hudson Bay, we initiated the first winter study of the shallow waters surrounding the Belchers, collecting conductivity-temperature-depth (CTD) profiles and conductivity-temperature (CT) time series using under-ice moorings, and collecting water samples and ice cores during four campaigns between January 2014 and March 2015. Tandem measurements of salinity and δ 18 O were made for the water and ice samples to discriminate between freshwater sources (river runoff and sea ice melt). We find that southeast Hudson Bay, and particularly the nearshore domain southeast of the Belchers, is distinguished in winter by the presence of river water and strong surface stratification, which runs counter to expectations for a system in which local freshwater remains frozen on land until spring freshet (May–June) and sea ice growth is adding brine to surface waters. The amount of river water around the Belcher Islands increased significantly from fall through to late winter according to δ 18 O records of ice. The accumulation of river water in surface waters during the winter is directly associated with an accumulation of brine, which considerably exceeds the capacity of local ice formation to produce brine. We therefore infer that brine is advected into the study area together with river water, and that interplay between these properties establishes and maintains the level of surface stratification throughout winter. With reference to a NEMO ocean model simulation of winter circulation in the study area, we propose a conceptual model in which winter river inflow into James Bay drives the northward transport of both river water and brine captured near the surface, with reductions in brine-driven deep convection in the area’s flaw leads. While past changes in winter oceanographic conditions and sea ice cannot be reconstructed from the few available scientific data, the presence of significant runoff in winter in southeast Hudson Bay implies heightened sensitivity to delayed freeze-up under a warmer climate, which will have the effect of reducing brine early in the winter, also promoting increased stratification and river plume transport. Article in Journal/Newspaper Belcher Islands Hudson Bay inuit La Grande River Sea ice James Bay Springer Nature (via Crossref) Belcher ENVELOPE(-94.172,-94.172,57.936,57.936) Belcher Islands ENVELOPE(-79.250,-79.250,56.184,56.184) Hudson Hudson Bay Winter River ENVELOPE(-113.003,-113.003,64.501,64.501) Estuaries and Coasts 43 4 756 786 |