Reversed flow of Atlantic deep water during the last glacial maximum
The meridional overturning circulation (MOC) of the Atlantic Ocean is considered to be one of the most important components of the climate system. This is because its warm surface currents, such as the Gulf Stream, redistribute huge amounts of energy from tropical to high latitudes and influence reg...
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ftunivcardiff:oai:https://orca.cardiff.ac.uk:11270 2023-05-15T17:28:34+02:00 Reversed flow of Atlantic deep water during the last glacial maximum Negre, César Zahn, Rainer Thomas, Alexander L. Masqué, Pere Henderson, Gideon M. Martínez-Méndez, Gema Hall, Ian Robert Mas, José L. 2010-11-04 https://orca.cardiff.ac.uk/id/eprint/11270/ https://doi.org/10.1038/nature09508 unknown Nature Publishing Negre, César, Zahn, Rainer https://orca.cardiff.ac.uk/view/cardiffauthors/A041118S.html, Thomas, Alexander L., Masqué, Pere, Henderson, Gideon M., Martínez-Méndez, Gema, Hall, Ian Robert https://orca.cardiff.ac.uk/view/cardiffauthors/A002402L.html orcid:0000-0001-6960-1419 orcid:0000-0001-6960-1419 and Mas, José L. 2010. Reversed flow of Atlantic deep water during the last glacial maximum. Nature 468 (7320) , pp. 84-88. 10.1038/nature09508 https://doi.org/10.1038/nature09508 doi:10.1038/nature09508 GC Oceanography QE Geology Article PeerReviewed 2010 ftunivcardiff https://doi.org/10.1038/nature09508 2022-10-20T22:34:33Z The meridional overturning circulation (MOC) of the Atlantic Ocean is considered to be one of the most important components of the climate system. This is because its warm surface currents, such as the Gulf Stream, redistribute huge amounts of energy from tropical to high latitudes and influence regional weather and climate patterns, whereas its lower limb ventilates the deep ocean and affects the storage of carbon in the abyss, away from the atmosphere. Despite its significance for future climate, the operation of the MOC under contrasting climates of the past remains controversial. Nutrient-based proxies1, 2 and recent model simulations3 indicate that during the Last Glacial Maximum the convective activity in the North Atlantic Ocean was much weaker than at present. In contrast, rate-sensitive radiogenic 231Pa/230Th isotope ratios from the North Atlantic have been interpreted to indicate only minor changes in MOC strength4, 5, 6. Here we show that the basin-scale abyssal circulation of the Atlantic Ocean was probably reversed during the Last Glacial Maximum and was dominated by northward water flow from the Southern Ocean. These conclusions are based on new high-resolution data from the South Atlantic Ocean that establish the basin-scale north to south gradient in 231Pa/230Th, and thus the direction of the deep ocean circulation. Our findings are consistent with nutrient-based proxies and argue that further analysis of 231Pa/230Th outside the North Atlantic basin will enhance our understanding of past ocean circulation, provided that spatial gradients are carefully considered. This broader perspective suggests that the modern pattern of the Atlantic MOC—with a prominent southerly flow of deep waters originating in the North Atlantic—arose only during the Holocene epoch. Article in Journal/Newspaper North Atlantic South Atlantic Ocean Southern Ocean Cardiff University: ORCA (Online Research @ Cardiff) Southern Ocean Nature 468 7320 84 88 |
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Cardiff University: ORCA (Online Research @ Cardiff) |
op_collection_id |
ftunivcardiff |
language |
unknown |
topic |
GC Oceanography QE Geology |
spellingShingle |
GC Oceanography QE Geology Negre, César Zahn, Rainer Thomas, Alexander L. Masqué, Pere Henderson, Gideon M. Martínez-Méndez, Gema Hall, Ian Robert Mas, José L. Reversed flow of Atlantic deep water during the last glacial maximum |
topic_facet |
GC Oceanography QE Geology |
description |
The meridional overturning circulation (MOC) of the Atlantic Ocean is considered to be one of the most important components of the climate system. This is because its warm surface currents, such as the Gulf Stream, redistribute huge amounts of energy from tropical to high latitudes and influence regional weather and climate patterns, whereas its lower limb ventilates the deep ocean and affects the storage of carbon in the abyss, away from the atmosphere. Despite its significance for future climate, the operation of the MOC under contrasting climates of the past remains controversial. Nutrient-based proxies1, 2 and recent model simulations3 indicate that during the Last Glacial Maximum the convective activity in the North Atlantic Ocean was much weaker than at present. In contrast, rate-sensitive radiogenic 231Pa/230Th isotope ratios from the North Atlantic have been interpreted to indicate only minor changes in MOC strength4, 5, 6. Here we show that the basin-scale abyssal circulation of the Atlantic Ocean was probably reversed during the Last Glacial Maximum and was dominated by northward water flow from the Southern Ocean. These conclusions are based on new high-resolution data from the South Atlantic Ocean that establish the basin-scale north to south gradient in 231Pa/230Th, and thus the direction of the deep ocean circulation. Our findings are consistent with nutrient-based proxies and argue that further analysis of 231Pa/230Th outside the North Atlantic basin will enhance our understanding of past ocean circulation, provided that spatial gradients are carefully considered. This broader perspective suggests that the modern pattern of the Atlantic MOC—with a prominent southerly flow of deep waters originating in the North Atlantic—arose only during the Holocene epoch. |
format |
Article in Journal/Newspaper |
author |
Negre, César Zahn, Rainer Thomas, Alexander L. Masqué, Pere Henderson, Gideon M. Martínez-Méndez, Gema Hall, Ian Robert Mas, José L. |
author_facet |
Negre, César Zahn, Rainer Thomas, Alexander L. Masqué, Pere Henderson, Gideon M. Martínez-Méndez, Gema Hall, Ian Robert Mas, José L. |
author_sort |
Negre, César |
title |
Reversed flow of Atlantic deep water during the last glacial maximum |
title_short |
Reversed flow of Atlantic deep water during the last glacial maximum |
title_full |
Reversed flow of Atlantic deep water during the last glacial maximum |
title_fullStr |
Reversed flow of Atlantic deep water during the last glacial maximum |
title_full_unstemmed |
Reversed flow of Atlantic deep water during the last glacial maximum |
title_sort |
reversed flow of atlantic deep water during the last glacial maximum |
publisher |
Nature Publishing |
publishDate |
2010 |
url |
https://orca.cardiff.ac.uk/id/eprint/11270/ https://doi.org/10.1038/nature09508 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
North Atlantic South Atlantic Ocean Southern Ocean |
genre_facet |
North Atlantic South Atlantic Ocean Southern Ocean |
op_relation |
Negre, César, Zahn, Rainer https://orca.cardiff.ac.uk/view/cardiffauthors/A041118S.html, Thomas, Alexander L., Masqué, Pere, Henderson, Gideon M., Martínez-Méndez, Gema, Hall, Ian Robert https://orca.cardiff.ac.uk/view/cardiffauthors/A002402L.html orcid:0000-0001-6960-1419 orcid:0000-0001-6960-1419 and Mas, José L. 2010. Reversed flow of Atlantic deep water during the last glacial maximum. Nature 468 (7320) , pp. 84-88. 10.1038/nature09508 https://doi.org/10.1038/nature09508 doi:10.1038/nature09508 |
op_doi |
https://doi.org/10.1038/nature09508 |
container_title |
Nature |
container_volume |
468 |
container_issue |
7320 |
container_start_page |
84 |
op_container_end_page |
88 |
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1766121330194776064 |