Step change in sea surface temperatures brings marine heat waves to sub-Arctic James Bay, Canada

Marine heat waves (MHWs) are recognized as pervasive drivers of impacts on marine species and ecosystems across the world; however, sub-Arctic areas that are rapidly losing seasonal sea-ice cover remain understudied. In this research, we examine a forty-year time series of MHW characteristics in the...

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Main Authors: Jennifer Ann Bruneau, Jens Kristian Ehn, Zou Zou Anna Kuzyk, Alex D. Crawford, Melanie Louise Leblanc
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-06-01
Series:Frontiers in Marine Science
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Online Access:https://www.frontiersin.org/articles/10.3389/fmars.2025.1549329/full
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author Jennifer Ann Bruneau
Jens Kristian Ehn
Jens Kristian Ehn
Zou Zou Anna Kuzyk
Zou Zou Anna Kuzyk
Alex D. Crawford
Alex D. Crawford
Melanie Louise Leblanc
author_facet Jennifer Ann Bruneau
Jens Kristian Ehn
Jens Kristian Ehn
Zou Zou Anna Kuzyk
Zou Zou Anna Kuzyk
Alex D. Crawford
Alex D. Crawford
Melanie Louise Leblanc
author_sort Jennifer Ann Bruneau
collection DOAJ
description Marine heat waves (MHWs) are recognized as pervasive drivers of impacts on marine species and ecosystems across the world; however, sub-Arctic areas that are rapidly losing seasonal sea-ice cover remain understudied. In this research, we examine a forty-year time series of MHW characteristics in the seasonally ice-covered James Bay region of the Canadian Inland Seas in central Canada. Through the period 1982 to 2021, we document the trends and investigate past MHW occurrences with respect to their driving processes. After only two MHW events during the early portion of the record (1982-1997), five events occurred in 1998 and signaled both an anomalous year and a step change in the region’s marine climatology. The new marine climate in the region is more variable with longer and more intense MHWs. Four or more MHWs occurred in each of 2001, 2005, 2010, 2012. Events in May and October 2021 lasted over a month in duration, with the former reaching intensities of between 2.5 and 3°C. MHW intensity was correlated with ice breakup date and positive Atlantic Multi-decadal Variability, which are suggested drivers of the increasing trends in sea surface temperatures. While the impacts of MHWs on marine and coastal ecosystems in the region remain unknown because of a lack of monitoring, the 1998 MHW intensification coincides with a massive decline in the region’s seagrass Zostera marina (eelgrass) ecosystem, which has been monitored since 1982. Given projections of more extreme MHWs under global warming and the sensitivity of marine species and ecosystems to warm water events, there is an urgent need to better tracks MHWs and investigate their role in shaping northern ecosystem changes.
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spelling doaj-art-3e32a30fd9a64d86a9efe3dccd789abf2025-08-20T03:18:30ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452025-06-011210.3389/fmars.2025.15493291549329Step change in sea surface temperatures brings marine heat waves to sub-Arctic James Bay, CanadaJennifer Ann Bruneau0Jens Kristian Ehn1Jens Kristian Ehn2Zou Zou Anna Kuzyk3Zou Zou Anna Kuzyk4Alex D. Crawford5Alex D. Crawford6Melanie Louise Leblanc7Centre for Earth Observation Science, University of Manitoba, Winnipeg, MB, CanadaCentre for Earth Observation Science, University of Manitoba, Winnipeg, MB, CanadaDepartment of Environment and Geography, University of Manitoba, Winnipeg, MB, CanadaCentre for Earth Observation Science, University of Manitoba, Winnipeg, MB, CanadaDepartment of Earth Sciences, University of Manitoba, Winnipeg, MB, CanadaCentre for Earth Observation Science, University of Manitoba, Winnipeg, MB, CanadaDepartment of Environment and Geography, University of Manitoba, Winnipeg, MB, CanadaNiskamoon Corporation, Chisasibi, QC, CanadaMarine heat waves (MHWs) are recognized as pervasive drivers of impacts on marine species and ecosystems across the world; however, sub-Arctic areas that are rapidly losing seasonal sea-ice cover remain understudied. In this research, we examine a forty-year time series of MHW characteristics in the seasonally ice-covered James Bay region of the Canadian Inland Seas in central Canada. Through the period 1982 to 2021, we document the trends and investigate past MHW occurrences with respect to their driving processes. After only two MHW events during the early portion of the record (1982-1997), five events occurred in 1998 and signaled both an anomalous year and a step change in the region’s marine climatology. The new marine climate in the region is more variable with longer and more intense MHWs. Four or more MHWs occurred in each of 2001, 2005, 2010, 2012. Events in May and October 2021 lasted over a month in duration, with the former reaching intensities of between 2.5 and 3°C. MHW intensity was correlated with ice breakup date and positive Atlantic Multi-decadal Variability, which are suggested drivers of the increasing trends in sea surface temperatures. While the impacts of MHWs on marine and coastal ecosystems in the region remain unknown because of a lack of monitoring, the 1998 MHW intensification coincides with a massive decline in the region’s seagrass Zostera marina (eelgrass) ecosystem, which has been monitored since 1982. Given projections of more extreme MHWs under global warming and the sensitivity of marine species and ecosystems to warm water events, there is an urgent need to better tracks MHWs and investigate their role in shaping northern ecosystem changes.https://www.frontiersin.org/articles/10.3389/fmars.2025.1549329/fullmarine heat wavesea surface temperaturesub-ArcticJames BayEl Niño, Eelgrass (Zostera marina)Hudson Bay
spellingShingle Jennifer Ann Bruneau
Jens Kristian Ehn
Jens Kristian Ehn
Zou Zou Anna Kuzyk
Zou Zou Anna Kuzyk
Alex D. Crawford
Alex D. Crawford
Melanie Louise Leblanc
Step change in sea surface temperatures brings marine heat waves to sub-Arctic James Bay, Canada
Frontiers in Marine Science
marine heat wave
sea surface temperature
sub-Arctic
James Bay
El Niño, Eelgrass (Zostera marina)
Hudson Bay
title Step change in sea surface temperatures brings marine heat waves to sub-Arctic James Bay, Canada
title_full Step change in sea surface temperatures brings marine heat waves to sub-Arctic James Bay, Canada
title_fullStr Step change in sea surface temperatures brings marine heat waves to sub-Arctic James Bay, Canada
title_full_unstemmed Step change in sea surface temperatures brings marine heat waves to sub-Arctic James Bay, Canada
title_short Step change in sea surface temperatures brings marine heat waves to sub-Arctic James Bay, Canada
title_sort step change in sea surface temperatures brings marine heat waves to sub arctic james bay canada
topic marine heat wave
sea surface temperature
sub-Arctic
James Bay
El Niño, Eelgrass (Zostera marina)
Hudson Bay
url https://www.frontiersin.org/articles/10.3389/fmars.2025.1549329/full
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