Rapidly Increasing Artificial Iodine Highlights Pathways of Iceland-Scotland Overflow Water and Labrador Sea Water
Iceland-Scotland Overflow Water (ISOW) and Labrador Seawater (LSW) are major water masses of the lower Atlantic Meridional Overturning Circulation (AMOC). Therefore, the investigation of their transport pathways is important to understand the structure of the AMOC and how climate properties are expo...
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2022
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Online Access: | https://doi.org/10.3389/fmars.2022.897729 https://doaj.org/article/c309161f2f9944a5b0238d30a606f0e9 |
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ftdoajarticles:oai:doaj.org/article:c309161f2f9944a5b0238d30a606f0e9 2023-05-15T16:30:18+02:00 Rapidly Increasing Artificial Iodine Highlights Pathways of Iceland-Scotland Overflow Water and Labrador Sea Water Maxi Castrillejo Núria Casacuberta Christof Vockenhuber Pascale Lherminier 2022-05-01T00:00:00Z https://doi.org/10.3389/fmars.2022.897729 https://doaj.org/article/c309161f2f9944a5b0238d30a606f0e9 EN eng Frontiers Media S.A. https://www.frontiersin.org/articles/10.3389/fmars.2022.897729/full https://doaj.org/toc/2296-7745 2296-7745 doi:10.3389/fmars.2022.897729 https://doaj.org/article/c309161f2f9944a5b0238d30a606f0e9 Frontiers in Marine Science, Vol 9 (2022) artificial radionuclides 129I ISOW LSW AMOC iodine Science Q General. Including nature conservation geographical distribution QH1-199.5 article 2022 ftdoajarticles https://doi.org/10.3389/fmars.2022.897729 2022-12-31T02:28:36Z Iceland-Scotland Overflow Water (ISOW) and Labrador Seawater (LSW) are major water masses of the lower Atlantic Meridional Overturning Circulation (AMOC). Therefore, the investigation of their transport pathways is important to understand the structure of the AMOC and how climate properties are exported from the North Atlantic to lower latitudes. There is growing evidence from Lagrangian model simulations and observations that ISOW and LSW detach from boundary currents and spread off-boundary, into the basin interior in the Atlantic Ocean. Nuclear fuel reprocessing facilities of Sellafield and La Hague have been releasing artificial iodine (129I) into the northeastern Atlantic since the 1960ies. As a result, 129I is supplied from north of the Greenland-Scotland passages into the subpolar region labelling waters of the southward flowing lower AMOC. To explore the potential of 129I as tracer of boundary and interior ISOW and LSW transport pathways, we analyzed the tracer concentrations in seawater collected during four oceanographic cruises in the subpolar and subtropical North Atlantic regions between 2017 and 2019. The new tracer observations showed that deep tracer maxima highlighted the spreading of ISOW along the flanks of Reykjanes Ridge, across fracture zones and into the eastern subpolar North Atlantic supporting recent Lagrangian studies. Further, we found that 129I is intruding the Atlantic Ocean at unprecedented rate and labelling much larger extensions and water masses than in the recent past. This has enabled the use of 129I for other purposes aside from tracing ISOW. For example, increasing tracer levels allowed us to differentiate between newly formed 129I-rich LSW and older vintages poorer in 129I content. Further, 129I concentration maxima at intermediate depths could be used to track the spreading of LSW beyond the subpolar region and far into subtropical seas near Bermuda. Considering that 129I releases from Sellafield and La Hague have increased or levelled off during the last decades, it is ... Article in Journal/Newspaper Greenland Iceland Labrador Sea North Atlantic Directory of Open Access Journals: DOAJ Articles Greenland Reykjanes ENVELOPE(-22.250,-22.250,65.467,65.467) Frontiers in Marine Science 9 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
artificial radionuclides 129I ISOW LSW AMOC iodine Science Q General. Including nature conservation geographical distribution QH1-199.5 |
spellingShingle |
artificial radionuclides 129I ISOW LSW AMOC iodine Science Q General. Including nature conservation geographical distribution QH1-199.5 Maxi Castrillejo Núria Casacuberta Christof Vockenhuber Pascale Lherminier Rapidly Increasing Artificial Iodine Highlights Pathways of Iceland-Scotland Overflow Water and Labrador Sea Water |
topic_facet |
artificial radionuclides 129I ISOW LSW AMOC iodine Science Q General. Including nature conservation geographical distribution QH1-199.5 |
description |
Iceland-Scotland Overflow Water (ISOW) and Labrador Seawater (LSW) are major water masses of the lower Atlantic Meridional Overturning Circulation (AMOC). Therefore, the investigation of their transport pathways is important to understand the structure of the AMOC and how climate properties are exported from the North Atlantic to lower latitudes. There is growing evidence from Lagrangian model simulations and observations that ISOW and LSW detach from boundary currents and spread off-boundary, into the basin interior in the Atlantic Ocean. Nuclear fuel reprocessing facilities of Sellafield and La Hague have been releasing artificial iodine (129I) into the northeastern Atlantic since the 1960ies. As a result, 129I is supplied from north of the Greenland-Scotland passages into the subpolar region labelling waters of the southward flowing lower AMOC. To explore the potential of 129I as tracer of boundary and interior ISOW and LSW transport pathways, we analyzed the tracer concentrations in seawater collected during four oceanographic cruises in the subpolar and subtropical North Atlantic regions between 2017 and 2019. The new tracer observations showed that deep tracer maxima highlighted the spreading of ISOW along the flanks of Reykjanes Ridge, across fracture zones and into the eastern subpolar North Atlantic supporting recent Lagrangian studies. Further, we found that 129I is intruding the Atlantic Ocean at unprecedented rate and labelling much larger extensions and water masses than in the recent past. This has enabled the use of 129I for other purposes aside from tracing ISOW. For example, increasing tracer levels allowed us to differentiate between newly formed 129I-rich LSW and older vintages poorer in 129I content. Further, 129I concentration maxima at intermediate depths could be used to track the spreading of LSW beyond the subpolar region and far into subtropical seas near Bermuda. Considering that 129I releases from Sellafield and La Hague have increased or levelled off during the last decades, it is ... |
format |
Article in Journal/Newspaper |
author |
Maxi Castrillejo Núria Casacuberta Christof Vockenhuber Pascale Lherminier |
author_facet |
Maxi Castrillejo Núria Casacuberta Christof Vockenhuber Pascale Lherminier |
author_sort |
Maxi Castrillejo |
title |
Rapidly Increasing Artificial Iodine Highlights Pathways of Iceland-Scotland Overflow Water and Labrador Sea Water |
title_short |
Rapidly Increasing Artificial Iodine Highlights Pathways of Iceland-Scotland Overflow Water and Labrador Sea Water |
title_full |
Rapidly Increasing Artificial Iodine Highlights Pathways of Iceland-Scotland Overflow Water and Labrador Sea Water |
title_fullStr |
Rapidly Increasing Artificial Iodine Highlights Pathways of Iceland-Scotland Overflow Water and Labrador Sea Water |
title_full_unstemmed |
Rapidly Increasing Artificial Iodine Highlights Pathways of Iceland-Scotland Overflow Water and Labrador Sea Water |
title_sort |
rapidly increasing artificial iodine highlights pathways of iceland-scotland overflow water and labrador sea water |
publisher |
Frontiers Media S.A. |
publishDate |
2022 |
url |
https://doi.org/10.3389/fmars.2022.897729 https://doaj.org/article/c309161f2f9944a5b0238d30a606f0e9 |
long_lat |
ENVELOPE(-22.250,-22.250,65.467,65.467) |
geographic |
Greenland Reykjanes |
geographic_facet |
Greenland Reykjanes |
genre |
Greenland Iceland Labrador Sea North Atlantic |
genre_facet |
Greenland Iceland Labrador Sea North Atlantic |
op_source |
Frontiers in Marine Science, Vol 9 (2022) |
op_relation |
https://www.frontiersin.org/articles/10.3389/fmars.2022.897729/full https://doaj.org/toc/2296-7745 2296-7745 doi:10.3389/fmars.2022.897729 https://doaj.org/article/c309161f2f9944a5b0238d30a606f0e9 |
op_doi |
https://doi.org/10.3389/fmars.2022.897729 |
container_title |
Frontiers in Marine Science |
container_volume |
9 |
_version_ |
1766020029863690240 |