Mesoscale features create hotspots of carbon uptake in the Antarctic Circumpolar Current
International audience The influence of eddy structures on the seasonal depletion of dissolved inorganic carbon (DIC) and carbon dioxide (CO 2 ) disequilibrium was investigated during a trans-Atlantic crossing of the Antarctic Circumpolar Current (ACC) in austral summer 2012. The Georgia Basin, down...
Published in: | Deep Sea Research Part II: Topical Studies in Oceanography |
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Online Access: | https://hal.science/hal-03859053 https://doi.org/10.1016/j.dsr2.2015.10.006 |
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ftunivnantes:oai:HAL:hal-03859053v1 2023-05-15T14:02:14+02:00 Mesoscale features create hotspots of carbon uptake in the Antarctic Circumpolar Current Jones, Elizabeth M. Hoppema, Mario Strass, Volker Hauck, Judith Salt, Lesley Ossebaar, Sharyn Klaas, Christine van Heuven, Steven M. A. C. Wolf-Gladrow, Dieter Stöven, Tim de Baar, Hein J. W. Station biologique de Roscoff Roscoff (SBR) Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS) 2017 https://hal.science/hal-03859053 https://doi.org/10.1016/j.dsr2.2015.10.006 en eng HAL CCSD info:eu-repo/semantics/altIdentifier/doi/10.1016/j.dsr2.2015.10.006 hal-03859053 https://hal.science/hal-03859053 BIBCODE: 2017DSRII.138.39J doi:10.1016/j.dsr2.2015.10.006 Deep-Sea Research Part II https://hal.science/hal-03859053 Deep-Sea Research Part II, 2017, 138, pp.39-51. ⟨10.1016/j.dsr2.2015.10.006⟩ Carbon uptake Eddies Polar Front Antarctic Circumpolar Current Georgia Basin [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/article Journal articles 2017 ftunivnantes https://doi.org/10.1016/j.dsr2.2015.10.006 2023-02-08T02:09:50Z International audience The influence of eddy structures on the seasonal depletion of dissolved inorganic carbon (DIC) and carbon dioxide (CO 2 ) disequilibrium was investigated during a trans-Atlantic crossing of the Antarctic Circumpolar Current (ACC) in austral summer 2012. The Georgia Basin, downstream of the island of South Georgia (54-55°S, 36-38°W) is a highly dynamic region due to the mesoscale activity associated with the flow of the Subantarctic Front (SAF) and Polar Front (PF). Satellite sea-surface height and chlorophyll-a anomalies revealed a cyclonic cold core that dominated the northern Georgia Basin that was formed from a large meander of the PF. Warmer waters influenced by the SAF formed a smaller anticyclonic structure to the east of the basin. Both the cold core and warm core eddy structures were hotspots of carbon uptake relative to the rest of the ACC section during austral summer. This was most amplified in the cold core where greatest CO 2 undersaturation (-78 μatm) and substantial surface ocean DIC deficit (5.1 mol m -2 ) occurred. In the presence of high wind speeds, the cold core eddy acted as a strong sink for atmospheric CO 2 of 25.5 mmol m -2 day -1 . Waters of the warm core displayed characteristics of the Polar Frontal Zone (PFZ), with warmer upper ocean waters and enhanced CO 2 undersaturation (-59 μatm) and depletion of DIC (4.9mol m -2 ). A proposed mechanism for the enhanced carbon uptake across both eddy structures is based on the Ekman eddy pumping theory: (i) the cold core is seeded with productive (high chlorophyll-a) waters from the Antarctic Zone and sustained biological productivity through upwelled nutrient supply that counteracts DIC inputs from deep waters; (ii) horizontal entrainment of low-DIC surface waters (biological uptake) from the PFZ downwell within the warm core and cause relative DIC-depletion in the upper water column. The observations suggest that the formation and northward propagation of cold core eddies in the region of the PF could project low-DIC ... Article in Journal/Newspaper Antarc* Antarctic Université de Nantes: HAL-UNIV-NANTES Antarctic Austral Georgia Basin ENVELOPE(-35.500,-35.500,-50.750,-50.750) The Antarctic Deep Sea Research Part II: Topical Studies in Oceanography 138 39 51 |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
English |
topic |
Carbon uptake Eddies Polar Front Antarctic Circumpolar Current Georgia Basin [SDU]Sciences of the Universe [physics] |
spellingShingle |
Carbon uptake Eddies Polar Front Antarctic Circumpolar Current Georgia Basin [SDU]Sciences of the Universe [physics] Jones, Elizabeth M. Hoppema, Mario Strass, Volker Hauck, Judith Salt, Lesley Ossebaar, Sharyn Klaas, Christine van Heuven, Steven M. A. C. Wolf-Gladrow, Dieter Stöven, Tim de Baar, Hein J. W. Mesoscale features create hotspots of carbon uptake in the Antarctic Circumpolar Current |
topic_facet |
Carbon uptake Eddies Polar Front Antarctic Circumpolar Current Georgia Basin [SDU]Sciences of the Universe [physics] |
description |
International audience The influence of eddy structures on the seasonal depletion of dissolved inorganic carbon (DIC) and carbon dioxide (CO 2 ) disequilibrium was investigated during a trans-Atlantic crossing of the Antarctic Circumpolar Current (ACC) in austral summer 2012. The Georgia Basin, downstream of the island of South Georgia (54-55°S, 36-38°W) is a highly dynamic region due to the mesoscale activity associated with the flow of the Subantarctic Front (SAF) and Polar Front (PF). Satellite sea-surface height and chlorophyll-a anomalies revealed a cyclonic cold core that dominated the northern Georgia Basin that was formed from a large meander of the PF. Warmer waters influenced by the SAF formed a smaller anticyclonic structure to the east of the basin. Both the cold core and warm core eddy structures were hotspots of carbon uptake relative to the rest of the ACC section during austral summer. This was most amplified in the cold core where greatest CO 2 undersaturation (-78 μatm) and substantial surface ocean DIC deficit (5.1 mol m -2 ) occurred. In the presence of high wind speeds, the cold core eddy acted as a strong sink for atmospheric CO 2 of 25.5 mmol m -2 day -1 . Waters of the warm core displayed characteristics of the Polar Frontal Zone (PFZ), with warmer upper ocean waters and enhanced CO 2 undersaturation (-59 μatm) and depletion of DIC (4.9mol m -2 ). A proposed mechanism for the enhanced carbon uptake across both eddy structures is based on the Ekman eddy pumping theory: (i) the cold core is seeded with productive (high chlorophyll-a) waters from the Antarctic Zone and sustained biological productivity through upwelled nutrient supply that counteracts DIC inputs from deep waters; (ii) horizontal entrainment of low-DIC surface waters (biological uptake) from the PFZ downwell within the warm core and cause relative DIC-depletion in the upper water column. The observations suggest that the formation and northward propagation of cold core eddies in the region of the PF could project low-DIC ... |
author2 |
Station biologique de Roscoff Roscoff (SBR) Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Jones, Elizabeth M. Hoppema, Mario Strass, Volker Hauck, Judith Salt, Lesley Ossebaar, Sharyn Klaas, Christine van Heuven, Steven M. A. C. Wolf-Gladrow, Dieter Stöven, Tim de Baar, Hein J. W. |
author_facet |
Jones, Elizabeth M. Hoppema, Mario Strass, Volker Hauck, Judith Salt, Lesley Ossebaar, Sharyn Klaas, Christine van Heuven, Steven M. A. C. Wolf-Gladrow, Dieter Stöven, Tim de Baar, Hein J. W. |
author_sort |
Jones, Elizabeth M. |
title |
Mesoscale features create hotspots of carbon uptake in the Antarctic Circumpolar Current |
title_short |
Mesoscale features create hotspots of carbon uptake in the Antarctic Circumpolar Current |
title_full |
Mesoscale features create hotspots of carbon uptake in the Antarctic Circumpolar Current |
title_fullStr |
Mesoscale features create hotspots of carbon uptake in the Antarctic Circumpolar Current |
title_full_unstemmed |
Mesoscale features create hotspots of carbon uptake in the Antarctic Circumpolar Current |
title_sort |
mesoscale features create hotspots of carbon uptake in the antarctic circumpolar current |
publisher |
HAL CCSD |
publishDate |
2017 |
url |
https://hal.science/hal-03859053 https://doi.org/10.1016/j.dsr2.2015.10.006 |
long_lat |
ENVELOPE(-35.500,-35.500,-50.750,-50.750) |
geographic |
Antarctic Austral Georgia Basin The Antarctic |
geographic_facet |
Antarctic Austral Georgia Basin The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Deep-Sea Research Part II https://hal.science/hal-03859053 Deep-Sea Research Part II, 2017, 138, pp.39-51. ⟨10.1016/j.dsr2.2015.10.006⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.dsr2.2015.10.006 hal-03859053 https://hal.science/hal-03859053 BIBCODE: 2017DSRII.138.39J doi:10.1016/j.dsr2.2015.10.006 |
op_doi |
https://doi.org/10.1016/j.dsr2.2015.10.006 |
container_title |
Deep Sea Research Part II: Topical Studies in Oceanography |
container_volume |
138 |
container_start_page |
39 |
op_container_end_page |
51 |
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1766272386714304512 |