The impact of meltwater discharge from the Greenland ice sheet on the Atlantic nutrient supply to the northwest European shelf
Projected future shoaling of the wintertime mixed layer in the northeast (NE) Atlantic has been shown to induce a regime shift in the main nutrient supply pathway from the Atlantic to the northwest European shelf (NWES) near the end of the 21st century. While reduced winter convection leads to a sub...
Published in: | Ocean Science |
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Copernicus Publications
2020
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00050401 2023-05-15T16:28:43+02:00 The impact of meltwater discharge from the Greenland ice sheet on the Atlantic nutrient supply to the northwest European shelf Mathis, Moritz Mikolajewicz, Uwe 2020-01 electronic https://doi.org/10.5194/os-16-167-2020 https://noa.gwlb.de/receive/cop_mods_00050401 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00050012/os-16-167-2020.pdf https://os.copernicus.org/articles/16/167/2020/os-16-167-2020.pdf eng eng Copernicus Publications Ocean Science -- http://www.bibliothek.uni-regensburg.de/ezeit/?2183769 -- http://www.copernicus.org/EGU/os/os.html -- 1812-0792 https://doi.org/10.5194/os-16-167-2020 https://noa.gwlb.de/receive/cop_mods_00050401 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00050012/os-16-167-2020.pdf https://os.copernicus.org/articles/16/167/2020/os-16-167-2020.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess CC-BY article Verlagsveröffentlichung article Text doc-type:article 2020 ftnonlinearchiv https://doi.org/10.5194/os-16-167-2020 2022-02-08T22:36:54Z Projected future shoaling of the wintertime mixed layer in the northeast (NE) Atlantic has been shown to induce a regime shift in the main nutrient supply pathway from the Atlantic to the northwest European shelf (NWES) near the end of the 21st century. While reduced winter convection leads to a substantial decrease in the vertical nutrient supply and biological productivity in the open ocean, vertical mixing processes at the shelf break maintain a connection to the subpycnocline nutrient pool and thus productivity on the shelf. Here, we investigate how meltwater discharge from the Greenland ice sheet (GIS), not yet taken into account, impacts the mixed layer shoaling and the regime shift in terms of spatial distribution and temporal variability. To this end, we have downscaled sensitivity experiments by a global Earth system model for various GIS melting rates with a regionally coupled ocean–atmosphere climate system model. The model results indicate that increasing GIS meltwater discharge leads to a general intensification of the regime shift. Atlantic subpycnocline water masses mixed up at the shelf break become richer in nutrients and thus further limit the projected nutrient decline on the shelf. Moreover, the stronger vertical nutrient gradient through the pycnocline results in an enhanced interannual variability of on-shelf nutrient fluxes which, however, do not significantly increase variations in nutrient concentrations and primary production on the shelf. Due to the impact of the GIS meltwater discharge on the NE Atlantic mixed layer depth, the regime shift becomes initiated earlier in the century. The effect on the onset timing, though, is found to be strongly damped by the weakening of the Atlantic meridional overturning circulation. A GIS melting rate that is even 10 times higher than expected for emission scenario Representative Concentration Pathway (RCP) 8.5 would not lead to an onset of the regime shift until the 2070s. Article in Journal/Newspaper Greenland Ice Sheet Niedersächsisches Online-Archiv NOA Greenland Ocean Science 16 1 167 193 |
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Open Polar |
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Niedersächsisches Online-Archiv NOA |
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ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
spellingShingle |
article Verlagsveröffentlichung Mathis, Moritz Mikolajewicz, Uwe The impact of meltwater discharge from the Greenland ice sheet on the Atlantic nutrient supply to the northwest European shelf |
topic_facet |
article Verlagsveröffentlichung |
description |
Projected future shoaling of the wintertime mixed layer in the northeast (NE) Atlantic has been shown to induce a regime shift in the main nutrient supply pathway from the Atlantic to the northwest European shelf (NWES) near the end of the 21st century. While reduced winter convection leads to a substantial decrease in the vertical nutrient supply and biological productivity in the open ocean, vertical mixing processes at the shelf break maintain a connection to the subpycnocline nutrient pool and thus productivity on the shelf. Here, we investigate how meltwater discharge from the Greenland ice sheet (GIS), not yet taken into account, impacts the mixed layer shoaling and the regime shift in terms of spatial distribution and temporal variability. To this end, we have downscaled sensitivity experiments by a global Earth system model for various GIS melting rates with a regionally coupled ocean–atmosphere climate system model. The model results indicate that increasing GIS meltwater discharge leads to a general intensification of the regime shift. Atlantic subpycnocline water masses mixed up at the shelf break become richer in nutrients and thus further limit the projected nutrient decline on the shelf. Moreover, the stronger vertical nutrient gradient through the pycnocline results in an enhanced interannual variability of on-shelf nutrient fluxes which, however, do not significantly increase variations in nutrient concentrations and primary production on the shelf. Due to the impact of the GIS meltwater discharge on the NE Atlantic mixed layer depth, the regime shift becomes initiated earlier in the century. The effect on the onset timing, though, is found to be strongly damped by the weakening of the Atlantic meridional overturning circulation. A GIS melting rate that is even 10 times higher than expected for emission scenario Representative Concentration Pathway (RCP) 8.5 would not lead to an onset of the regime shift until the 2070s. |
format |
Article in Journal/Newspaper |
author |
Mathis, Moritz Mikolajewicz, Uwe |
author_facet |
Mathis, Moritz Mikolajewicz, Uwe |
author_sort |
Mathis, Moritz |
title |
The impact of meltwater discharge from the Greenland ice sheet on the Atlantic nutrient supply to the northwest European shelf |
title_short |
The impact of meltwater discharge from the Greenland ice sheet on the Atlantic nutrient supply to the northwest European shelf |
title_full |
The impact of meltwater discharge from the Greenland ice sheet on the Atlantic nutrient supply to the northwest European shelf |
title_fullStr |
The impact of meltwater discharge from the Greenland ice sheet on the Atlantic nutrient supply to the northwest European shelf |
title_full_unstemmed |
The impact of meltwater discharge from the Greenland ice sheet on the Atlantic nutrient supply to the northwest European shelf |
title_sort |
impact of meltwater discharge from the greenland ice sheet on the atlantic nutrient supply to the northwest european shelf |
publisher |
Copernicus Publications |
publishDate |
2020 |
url |
https://doi.org/10.5194/os-16-167-2020 https://noa.gwlb.de/receive/cop_mods_00050401 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00050012/os-16-167-2020.pdf https://os.copernicus.org/articles/16/167/2020/os-16-167-2020.pdf |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet |
genre_facet |
Greenland Ice Sheet |
op_relation |
Ocean Science -- http://www.bibliothek.uni-regensburg.de/ezeit/?2183769 -- http://www.copernicus.org/EGU/os/os.html -- 1812-0792 https://doi.org/10.5194/os-16-167-2020 https://noa.gwlb.de/receive/cop_mods_00050401 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00050012/os-16-167-2020.pdf https://os.copernicus.org/articles/16/167/2020/os-16-167-2020.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/os-16-167-2020 |
container_title |
Ocean Science |
container_volume |
16 |
container_issue |
1 |
container_start_page |
167 |
op_container_end_page |
193 |
_version_ |
1766018396635267072 |