Oxygen Saturation Surrounding Deep Water Formation Events in the Labrador Sea From Argo-O-2 Data
Deep water formation supplies oxygen-rich water to the deep sea, spreading throughout the ocean by means of the global thermohaline circulation. Models suggest that dissolved gases in newly formed deep water do not come to equilibrium with the atmosphere. However, direct measurements during winterti...
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ftarchimer:oai:archimer.ifremer.fr:55329 2023-05-15T17:05:57+02:00 Oxygen Saturation Surrounding Deep Water Formation Events in the Labrador Sea From Argo-O-2 Data Wolf, Mitchell K. Hamme, Roberta C. Gilbert, Denis Yashayaev, Igor Thierry, Virginie 2018-04 application/pdf https://archimer.ifremer.fr/doc/00442/55329/56829.pdf https://archimer.ifremer.fr/doc/00442/55329/56830.pdf https://doi.org/10.1002/2017GB005829 https://archimer.ifremer.fr/doc/00442/55329/ eng eng Amer Geophysical Union https://archimer.ifremer.fr/doc/00442/55329/56829.pdf https://archimer.ifremer.fr/doc/00442/55329/56830.pdf doi:10.1002/2017GB005829 https://archimer.ifremer.fr/doc/00442/55329/ 2018. American Geophysical Union. All Rights Reserved. info:eu-repo/semantics/openAccess restricted use Global Biogeochemical Cycles (0886-6236) (Amer Geophysical Union), 2018-04 , Vol. 32 , N. 4 , P. 635-653 oxygen saturation convection Argo Labrador Sea deep water formation text Publication info:eu-repo/semantics/article 2018 ftarchimer https://doi.org/10.1002/2017GB005829 2021-09-23T20:31:06Z Deep water formation supplies oxygen-rich water to the deep sea, spreading throughout the ocean by means of the global thermohaline circulation. Models suggest that dissolved gases in newly formed deep water do not come to equilibrium with the atmosphere. However, direct measurements during wintertime convection are scarce, and the controls over the extent of these disequilibria are poorly quantified. Here we show that, when convection reached deeper than 800 m, oxygen in the Labrador Sea was consistently undersaturated at -6.1% to -7.6% at the end of convection. Deeper convection resulted in greater undersaturation, while convection ending later in the year resulted in values closer to equilibrium, from which we produce a predictive relationship. We use dissolved oxygen data from six profiling Argo floats in the Labrador Sea between 2003 and 2016, allowing direct observations of wintertime convection. Three of the six optode oxygen sensors displayed substantial average in situ drift of -3.03 mu mol O-2 kg(-1)yr(-1) (-0.94% O-2 yr(-1)), which we corrected to stable deepwater oxygen values from repeat ship surveys. Observations of low oxygen intrusions during restratification and a simple mixing calculation demonstrate that lateral processes act to lower the oxygen inventory of the central Labrador Sea. This suggests that the Labrador Sea is a net sink for atmospheric oxygen, but uncertainties in parameterizing gas exchange limit our ability to quantify the net uptake. Our results constrain the oxygen concentration of newly formed Labrador Sea Water and allow more precise estimates of oxygen utilization and nutrient regeneration in this water mass. Article in Journal/Newspaper Labrador Sea Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Global Biogeochemical Cycles 32 4 635 653 |
institution |
Open Polar |
collection |
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
topic |
oxygen saturation convection Argo Labrador Sea deep water formation |
spellingShingle |
oxygen saturation convection Argo Labrador Sea deep water formation Wolf, Mitchell K. Hamme, Roberta C. Gilbert, Denis Yashayaev, Igor Thierry, Virginie Oxygen Saturation Surrounding Deep Water Formation Events in the Labrador Sea From Argo-O-2 Data |
topic_facet |
oxygen saturation convection Argo Labrador Sea deep water formation |
description |
Deep water formation supplies oxygen-rich water to the deep sea, spreading throughout the ocean by means of the global thermohaline circulation. Models suggest that dissolved gases in newly formed deep water do not come to equilibrium with the atmosphere. However, direct measurements during wintertime convection are scarce, and the controls over the extent of these disequilibria are poorly quantified. Here we show that, when convection reached deeper than 800 m, oxygen in the Labrador Sea was consistently undersaturated at -6.1% to -7.6% at the end of convection. Deeper convection resulted in greater undersaturation, while convection ending later in the year resulted in values closer to equilibrium, from which we produce a predictive relationship. We use dissolved oxygen data from six profiling Argo floats in the Labrador Sea between 2003 and 2016, allowing direct observations of wintertime convection. Three of the six optode oxygen sensors displayed substantial average in situ drift of -3.03 mu mol O-2 kg(-1)yr(-1) (-0.94% O-2 yr(-1)), which we corrected to stable deepwater oxygen values from repeat ship surveys. Observations of low oxygen intrusions during restratification and a simple mixing calculation demonstrate that lateral processes act to lower the oxygen inventory of the central Labrador Sea. This suggests that the Labrador Sea is a net sink for atmospheric oxygen, but uncertainties in parameterizing gas exchange limit our ability to quantify the net uptake. Our results constrain the oxygen concentration of newly formed Labrador Sea Water and allow more precise estimates of oxygen utilization and nutrient regeneration in this water mass. |
format |
Article in Journal/Newspaper |
author |
Wolf, Mitchell K. Hamme, Roberta C. Gilbert, Denis Yashayaev, Igor Thierry, Virginie |
author_facet |
Wolf, Mitchell K. Hamme, Roberta C. Gilbert, Denis Yashayaev, Igor Thierry, Virginie |
author_sort |
Wolf, Mitchell K. |
title |
Oxygen Saturation Surrounding Deep Water Formation Events in the Labrador Sea From Argo-O-2 Data |
title_short |
Oxygen Saturation Surrounding Deep Water Formation Events in the Labrador Sea From Argo-O-2 Data |
title_full |
Oxygen Saturation Surrounding Deep Water Formation Events in the Labrador Sea From Argo-O-2 Data |
title_fullStr |
Oxygen Saturation Surrounding Deep Water Formation Events in the Labrador Sea From Argo-O-2 Data |
title_full_unstemmed |
Oxygen Saturation Surrounding Deep Water Formation Events in the Labrador Sea From Argo-O-2 Data |
title_sort |
oxygen saturation surrounding deep water formation events in the labrador sea from argo-o-2 data |
publisher |
Amer Geophysical Union |
publishDate |
2018 |
url |
https://archimer.ifremer.fr/doc/00442/55329/56829.pdf https://archimer.ifremer.fr/doc/00442/55329/56830.pdf https://doi.org/10.1002/2017GB005829 https://archimer.ifremer.fr/doc/00442/55329/ |
genre |
Labrador Sea |
genre_facet |
Labrador Sea |
op_source |
Global Biogeochemical Cycles (0886-6236) (Amer Geophysical Union), 2018-04 , Vol. 32 , N. 4 , P. 635-653 |
op_relation |
https://archimer.ifremer.fr/doc/00442/55329/56829.pdf https://archimer.ifremer.fr/doc/00442/55329/56830.pdf doi:10.1002/2017GB005829 https://archimer.ifremer.fr/doc/00442/55329/ |
op_rights |
2018. American Geophysical Union. All Rights Reserved. info:eu-repo/semantics/openAccess restricted use |
op_doi |
https://doi.org/10.1002/2017GB005829 |
container_title |
Global Biogeochemical Cycles |
container_volume |
32 |
container_issue |
4 |
container_start_page |
635 |
op_container_end_page |
653 |
_version_ |
1766060827965652992 |