Summer trends and drivers of sea surface fCO2 and pH changes observed in the southern Indian Ocean over the last two decades (1998–2019)
The decadal changes of the fugacity of CO2 (fCO2) and pH in surface waters are investigated in the Southern Indian Ocean (45° S–57° S) using repeated summer observations, including measurements of fCO2, total alkalinity (AT) and total carbon (CT) collected over the period 1998–2019 in the frame of t...
Published in: | Biogeosciences |
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Format: | Article in Journal/Newspaper |
Language: | English |
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Copernicus GmbH
2022
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Online Access: | https://archimer.ifremer.fr/doc/00749/86117/91332.pdf https://archimer.ifremer.fr/doc/00749/86117/91333.pdf https://archimer.ifremer.fr/doc/00749/86117/94176.pdf https://archimer.ifremer.fr/doc/00749/86117/94177.pdf https://doi.org/10.5194/bg-19-2599-2022 https://archimer.ifremer.fr/doc/00749/86117/ |
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ftarchimer:oai:archimer.ifremer.fr:86117 2023-05-15T17:02:05+02:00 Summer trends and drivers of sea surface fCO2 and pH changes observed in the southern Indian Ocean over the last two decades (1998–2019) Leseurre, Coraline Lo Monaco, Claire Reverdin, Gilles Metzl, Nicolas Fin, Jonathan Mignon, Claude Benito, Léa 2022-05 application/pdf https://archimer.ifremer.fr/doc/00749/86117/91332.pdf https://archimer.ifremer.fr/doc/00749/86117/91333.pdf https://archimer.ifremer.fr/doc/00749/86117/94176.pdf https://archimer.ifremer.fr/doc/00749/86117/94177.pdf https://doi.org/10.5194/bg-19-2599-2022 https://archimer.ifremer.fr/doc/00749/86117/ eng eng Copernicus GmbH https://archimer.ifremer.fr/doc/00749/86117/91332.pdf https://archimer.ifremer.fr/doc/00749/86117/91333.pdf https://archimer.ifremer.fr/doc/00749/86117/94176.pdf https://archimer.ifremer.fr/doc/00749/86117/94177.pdf doi:10.5194/bg-19-2599-2022 https://archimer.ifremer.fr/doc/00749/86117/ info:eu-repo/semantics/openAccess restricted use Biogeosciences (1726-4170) (Copernicus GmbH), 2022-05 , Vol. 19 , N. 10 , P. 2599-2625 text Publication info:eu-repo/semantics/article 2022 ftarchimer https://doi.org/10.5194/bg-19-2599-2022 2023-03-14T23:55:18Z The decadal changes of the fugacity of CO2 (fCO2) and pH in surface waters are investigated in the Southern Indian Ocean (45° S–57° S) using repeated summer observations, including measurements of fCO2, total alkalinity (AT) and total carbon (CT) collected over the period 1998–2019 in the frame of the French monitoring program OISO. We used three datasets (underway fCO2, underway AT-CT and station AT-CT) to evaluate the trends of fCO2 and pH and their drivers, including the accumulation of anthropogenic CO2 (Cant). The study region is separated into three domains based on the frontal system and biogeochemical characteristics: (i) High Nutrients Low Chlorophyll (HNLC) waters in the Polar Front Zone (PFZ), (ii) HNLC waters south of the Polar Front (PF) and (iii) the highly productive zones in fertilized waters near Crozet and Kerguelen Islands. Almost everywhere, we obtained similar trends in surface fCO2 and pH using the fCO2 or AT-CT datasets. Over the period 1998–2019, we observed an increase in surface fCO2 and a decrease in pH ranging from +1.0 to +4.0 µatm yr−1 and from −0.0015 to −0.0043 yr−1, respectively. South of the PF, the fCO2 trend is close to the atmospheric CO2 rise (+2.0 µatm yr−1) and the decrease in pH is in the range of the mean trend for the global ocean (around −0.0020 yr−1); these trends are driven by the warming of surface waters (up to +0.04 °C yr−1) and the increase in CT, mainly due to the accumulation of Cant (around +0.6 µmol kg−1 yr−1). In the PFZ, our data show slower fCO2 and pH trends (around +1.3 µatm yr−1 and −0.0013 yr−1, respectively) associated with an increase in AT (around +0.4 µmol kg−1 yr−1) that limited the impact of a more rapid accumulation of Cant north of the PF (up to +1.1 µmol kg−1 yr−1). In the fertilized waters near Crozet and Kerguelen Islands, fCO2 increased and pH decreased faster than in the other domains, between +2.2 and +4.0 µatm yr−1 and between −0.0023 yr−1 and −0.0043 yr−1. The fastest trends of fCO2 and pH are found around Kerguelen Island north and ... Article in Journal/Newspaper Kerguelen Islands Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Indian Kerguelen Kerguelen Island ENVELOPE(69.500,69.500,-49.250,-49.250) Kerguelen Islands Biogeosciences 19 10 2599 2625 |
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 |
description |
The decadal changes of the fugacity of CO2 (fCO2) and pH in surface waters are investigated in the Southern Indian Ocean (45° S–57° S) using repeated summer observations, including measurements of fCO2, total alkalinity (AT) and total carbon (CT) collected over the period 1998–2019 in the frame of the French monitoring program OISO. We used three datasets (underway fCO2, underway AT-CT and station AT-CT) to evaluate the trends of fCO2 and pH and their drivers, including the accumulation of anthropogenic CO2 (Cant). The study region is separated into three domains based on the frontal system and biogeochemical characteristics: (i) High Nutrients Low Chlorophyll (HNLC) waters in the Polar Front Zone (PFZ), (ii) HNLC waters south of the Polar Front (PF) and (iii) the highly productive zones in fertilized waters near Crozet and Kerguelen Islands. Almost everywhere, we obtained similar trends in surface fCO2 and pH using the fCO2 or AT-CT datasets. Over the period 1998–2019, we observed an increase in surface fCO2 and a decrease in pH ranging from +1.0 to +4.0 µatm yr−1 and from −0.0015 to −0.0043 yr−1, respectively. South of the PF, the fCO2 trend is close to the atmospheric CO2 rise (+2.0 µatm yr−1) and the decrease in pH is in the range of the mean trend for the global ocean (around −0.0020 yr−1); these trends are driven by the warming of surface waters (up to +0.04 °C yr−1) and the increase in CT, mainly due to the accumulation of Cant (around +0.6 µmol kg−1 yr−1). In the PFZ, our data show slower fCO2 and pH trends (around +1.3 µatm yr−1 and −0.0013 yr−1, respectively) associated with an increase in AT (around +0.4 µmol kg−1 yr−1) that limited the impact of a more rapid accumulation of Cant north of the PF (up to +1.1 µmol kg−1 yr−1). In the fertilized waters near Crozet and Kerguelen Islands, fCO2 increased and pH decreased faster than in the other domains, between +2.2 and +4.0 µatm yr−1 and between −0.0023 yr−1 and −0.0043 yr−1. The fastest trends of fCO2 and pH are found around Kerguelen Island north and ... |
format |
Article in Journal/Newspaper |
author |
Leseurre, Coraline Lo Monaco, Claire Reverdin, Gilles Metzl, Nicolas Fin, Jonathan Mignon, Claude Benito, Léa |
spellingShingle |
Leseurre, Coraline Lo Monaco, Claire Reverdin, Gilles Metzl, Nicolas Fin, Jonathan Mignon, Claude Benito, Léa Summer trends and drivers of sea surface fCO2 and pH changes observed in the southern Indian Ocean over the last two decades (1998–2019) |
author_facet |
Leseurre, Coraline Lo Monaco, Claire Reverdin, Gilles Metzl, Nicolas Fin, Jonathan Mignon, Claude Benito, Léa |
author_sort |
Leseurre, Coraline |
title |
Summer trends and drivers of sea surface fCO2 and pH changes observed in the southern Indian Ocean over the last two decades (1998–2019) |
title_short |
Summer trends and drivers of sea surface fCO2 and pH changes observed in the southern Indian Ocean over the last two decades (1998–2019) |
title_full |
Summer trends and drivers of sea surface fCO2 and pH changes observed in the southern Indian Ocean over the last two decades (1998–2019) |
title_fullStr |
Summer trends and drivers of sea surface fCO2 and pH changes observed in the southern Indian Ocean over the last two decades (1998–2019) |
title_full_unstemmed |
Summer trends and drivers of sea surface fCO2 and pH changes observed in the southern Indian Ocean over the last two decades (1998–2019) |
title_sort |
summer trends and drivers of sea surface fco2 and ph changes observed in the southern indian ocean over the last two decades (1998–2019) |
publisher |
Copernicus GmbH |
publishDate |
2022 |
url |
https://archimer.ifremer.fr/doc/00749/86117/91332.pdf https://archimer.ifremer.fr/doc/00749/86117/91333.pdf https://archimer.ifremer.fr/doc/00749/86117/94176.pdf https://archimer.ifremer.fr/doc/00749/86117/94177.pdf https://doi.org/10.5194/bg-19-2599-2022 https://archimer.ifremer.fr/doc/00749/86117/ |
long_lat |
ENVELOPE(69.500,69.500,-49.250,-49.250) |
geographic |
Indian Kerguelen Kerguelen Island Kerguelen Islands |
geographic_facet |
Indian Kerguelen Kerguelen Island Kerguelen Islands |
genre |
Kerguelen Islands |
genre_facet |
Kerguelen Islands |
op_source |
Biogeosciences (1726-4170) (Copernicus GmbH), 2022-05 , Vol. 19 , N. 10 , P. 2599-2625 |
op_relation |
https://archimer.ifremer.fr/doc/00749/86117/91332.pdf https://archimer.ifremer.fr/doc/00749/86117/91333.pdf https://archimer.ifremer.fr/doc/00749/86117/94176.pdf https://archimer.ifremer.fr/doc/00749/86117/94177.pdf doi:10.5194/bg-19-2599-2022 https://archimer.ifremer.fr/doc/00749/86117/ |
op_rights |
info:eu-repo/semantics/openAccess restricted use |
op_doi |
https://doi.org/10.5194/bg-19-2599-2022 |
container_title |
Biogeosciences |
container_volume |
19 |
container_issue |
10 |
container_start_page |
2599 |
op_container_end_page |
2625 |
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1766055324660269056 |