Modelling the bottom-up effects of climate change on primary production in the Gulf of St. Lawrence and eastern Scotian Shelf

The Gulf of St. Lawrence (GSL), along with the St. Lawrence Estuary, is the largest estuarine system in North America. It is a biologically productive sea and an important fishing ground in Canada. The objectives of this study are to determine how climate changes will affect primary production in th...

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Main Authors: Zhi-Ping Mei, Diane Lavoie, Nicolas Lambert, Michel Starr, Joël Chassé, William Perrie, Zhenxia Long
Format: Article
Language:English
Published: Frontiers Media S.A. 2024-08-01
Series:Frontiers in Marine Science
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Online Access:https://www.frontiersin.org/articles/10.3389/fmars.2024.1416744/full
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author Zhi-Ping Mei
Diane Lavoie
Nicolas Lambert
Nicolas Lambert
Michel Starr
Joël Chassé
William Perrie
Zhenxia Long
author_facet Zhi-Ping Mei
Diane Lavoie
Nicolas Lambert
Nicolas Lambert
Michel Starr
Joël Chassé
William Perrie
Zhenxia Long
author_sort Zhi-Ping Mei
collection DOAJ
description The Gulf of St. Lawrence (GSL), along with the St. Lawrence Estuary, is the largest estuarine system in North America. It is a biologically productive sea and an important fishing ground in Canada. The objectives of this study are to determine how climate changes will affect primary production in the GSL and on the eastern Scotian Shelf, and to determine the drivers of the changes. We use a regional ocean model forced with downscaled output of the Max-Planck Institute Earth System Model to study the changes in net primary production under the climate change scenario of Representative Concentration Pathway 8.5 (RCP8.5). Results reveal a projected 13.4% decrease in annual primary production across the GSL system over the next 70 years. This decline primarily stems from reduced nutrient concentrations in the upper layer, despite the increase in nutrients supplied by rivers. Enhanced freshwater influx and ocean surface warming contribute to heightened stratification, that in turn reduce the vertical nutrient fluxes from deeper layers. This mechanism affects the upwelling of nutrient-rich water at the head of the Laurentian Channel in the Lower St. Lawrence Estuary, leading to a 22% reduction in the vertical nitrate flux in the future. Additionally, nutrient concentrations in the water masses entering the GSL at the Strait of Belle Isle and at Cabot Strait are also reduced. Due to declining sea-ice concentration, the phytoplankton bloom is expected to occur between 9 and 23 days earlier under a warmer climate, and last for up to 24 days longer, depending on the GSL subregions, compared to the historical period (2001-2020). Biological productivity at higher trophic levels, and thus fisheries productivity, could be negatively impacted under the RCP8.5 climate change scenario.
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spelling doaj-art-feed95c6b64c460d945a47219e15e5d52025-08-20T01:57:19ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452024-08-011110.3389/fmars.2024.14167441416744Modelling the bottom-up effects of climate change on primary production in the Gulf of St. Lawrence and eastern Scotian ShelfZhi-Ping Mei0Diane Lavoie1Nicolas Lambert2Nicolas Lambert3Michel Starr4Joël Chassé5William Perrie6Zhenxia Long7Bedford Institute of Oceanography, Fisheries and Oceans Canada, Dartmouth, NS, CanadaMaurice-Lamontagne Institute, Fisheries and Oceans Canada, Mont-Joli, QC, CanadaGulf Fisheries Centre, Fisheries and Oceans Canada, Moncton, NB, CanadaCanadian Centre for Climate Modelling and Analysis, Environment and Climate Change Canada, Victoria, BC, CanadaMaurice-Lamontagne Institute, Fisheries and Oceans Canada, Mont-Joli, QC, CanadaGulf Fisheries Centre, Fisheries and Oceans Canada, Moncton, NB, CanadaBedford Institute of Oceanography, Fisheries and Oceans Canada, Dartmouth, NS, CanadaBedford Institute of Oceanography, Fisheries and Oceans Canada, Dartmouth, NS, CanadaThe Gulf of St. Lawrence (GSL), along with the St. Lawrence Estuary, is the largest estuarine system in North America. It is a biologically productive sea and an important fishing ground in Canada. The objectives of this study are to determine how climate changes will affect primary production in the GSL and on the eastern Scotian Shelf, and to determine the drivers of the changes. We use a regional ocean model forced with downscaled output of the Max-Planck Institute Earth System Model to study the changes in net primary production under the climate change scenario of Representative Concentration Pathway 8.5 (RCP8.5). Results reveal a projected 13.4% decrease in annual primary production across the GSL system over the next 70 years. This decline primarily stems from reduced nutrient concentrations in the upper layer, despite the increase in nutrients supplied by rivers. Enhanced freshwater influx and ocean surface warming contribute to heightened stratification, that in turn reduce the vertical nutrient fluxes from deeper layers. This mechanism affects the upwelling of nutrient-rich water at the head of the Laurentian Channel in the Lower St. Lawrence Estuary, leading to a 22% reduction in the vertical nitrate flux in the future. Additionally, nutrient concentrations in the water masses entering the GSL at the Strait of Belle Isle and at Cabot Strait are also reduced. Due to declining sea-ice concentration, the phytoplankton bloom is expected to occur between 9 and 23 days earlier under a warmer climate, and last for up to 24 days longer, depending on the GSL subregions, compared to the historical period (2001-2020). Biological productivity at higher trophic levels, and thus fisheries productivity, could be negatively impacted under the RCP8.5 climate change scenario.https://www.frontiersin.org/articles/10.3389/fmars.2024.1416744/fullclimate changeGulf of St. LawrenceEastern Scotian Shelfprimary productionnutrient supplyestuarine circulation
spellingShingle Zhi-Ping Mei
Diane Lavoie
Nicolas Lambert
Nicolas Lambert
Michel Starr
Joël Chassé
William Perrie
Zhenxia Long
Modelling the bottom-up effects of climate change on primary production in the Gulf of St. Lawrence and eastern Scotian Shelf
Frontiers in Marine Science
climate change
Gulf of St. Lawrence
Eastern Scotian Shelf
primary production
nutrient supply
estuarine circulation
title Modelling the bottom-up effects of climate change on primary production in the Gulf of St. Lawrence and eastern Scotian Shelf
title_full Modelling the bottom-up effects of climate change on primary production in the Gulf of St. Lawrence and eastern Scotian Shelf
title_fullStr Modelling the bottom-up effects of climate change on primary production in the Gulf of St. Lawrence and eastern Scotian Shelf
title_full_unstemmed Modelling the bottom-up effects of climate change on primary production in the Gulf of St. Lawrence and eastern Scotian Shelf
title_short Modelling the bottom-up effects of climate change on primary production in the Gulf of St. Lawrence and eastern Scotian Shelf
title_sort modelling the bottom up effects of climate change on primary production in the gulf of st lawrence and eastern scotian shelf
topic climate change
Gulf of St. Lawrence
Eastern Scotian Shelf
primary production
nutrient supply
estuarine circulation
url https://www.frontiersin.org/articles/10.3389/fmars.2024.1416744/full
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