Stability of alkalinity in ocean alkalinity enhancement (OAE) approaches -consequences for durability of CO2 storage
According to modelling studies, ocean alkalinity enhancement (OAE) is one of the proposed carbon dioxide removal (CDR) approaches with large potential, with the beneficial side effect of counteracting ocean acidification. The real-world application of OAE, however, remains unclear as most basic assu...
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Online Access: | http://hdl.handle.net/10553/123136 https://doi.org/10.5194/bg-20-781-2023 |
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ftunivlaspalmas:oai:accedacris.ulpgc.es:10553/123136 2023-06-18T03:42:30+02:00 Stability of alkalinity in ocean alkalinity enhancement (OAE) approaches -consequences for durability of CO2 storage Hartmann, Jens Suitner, Niels Lim, Carl Schneider, Julieta Marín Samper, Laura Arístegui Ruiz, Javier Renforth, Phil Taucher, Jan Riebesell, Ulf orcid:0000-0003-1878-9321 orcid:0000-0003-3413-857X orcid:0000-0002-9035-4771 orcid:0000-0002-7271-717X #NODATA# orcid:0000-0002-9442-452X BU-BAS 2023 http://hdl.handle.net/10553/123136 https://doi.org/10.5194/bg-20-781-2023 eng eng Biogeosciences 20 1726-4170 http://hdl.handle.net/10553/123136 doi:10.5194/bg-20-781-2023 2-s2.0-85148762615 WOS:000936330500001 4 Sí Biogeosciences [ISSN 1726-4170], v. 20 (4), p. 781–802, (2023) 251002 Oceanografía química 251001 Oceanografía biológica info:eu-repo/semantics/article Article 2023 ftunivlaspalmas https://doi.org/10.5194/bg-20-781-2023 2023-06-06T23:20:59Z According to modelling studies, ocean alkalinity enhancement (OAE) is one of the proposed carbon dioxide removal (CDR) approaches with large potential, with the beneficial side effect of counteracting ocean acidification. The real-world application of OAE, however, remains unclear as most basic assumptions are untested. Before large-scale deployment can be considered, safe and sustainable procedures for the addition of alkalinity to seawater must be identified and governance established. One of the concerns is the stability of alkalinity when added to seawater. The surface ocean is already supersaturated with respect to calcite and aragonite, and an increase in total alkalinity (TA) together with a corresponding shift in carbonate chemistry towards higher carbonate ion concentrations would result in a further increase in supersaturation, and potentially to solid carbonate precipitation. Precipitation of carbonate minerals consumes alkalinity and increases dissolved CO2 in seawater, thereby reducing the efficiency of OAE for CO2 removal. In order to address the application of alkaline solution as well as fine particulate alkaline solids, a set of six experiments was performed using natural seawater with alkalinity of around 2400μmol kgsw-1. The application of CO2-equilibrated alkaline solution bears the lowest risk of losing alkalinity due to carbonate phase formation if added total alkalinity (δTA) is less than 2400μmol kgsw-1. The addition of reactive alkaline solids can cause a net loss of alkalinity if added δTA>600μmol kgsw-1 (e.g. for Mg(OH)2). Commercially available (ultrafine) Ca(OH)2 causes, in general, a net loss in TA for the tested amounts of TA addition, which has consequences for suggested use of slurries with alkaline solids supplied from ships. The rapid application of excessive amounts of Ca(OH)2, exceeding a threshold for alkalinity loss, resulted in a massive increase in TA (>20000μmol kgsw-1) at the cost of lower efficiency and resultant high pH values >9.5. Analysis of precipitates ... Article in Journal/Newspaper Ocean acidification Universidad de Las Palmas de Gran Canaria: Acceda Biogeosciences 20 4 781 802 |
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Open Polar |
collection |
Universidad de Las Palmas de Gran Canaria: Acceda |
op_collection_id |
ftunivlaspalmas |
language |
English |
topic |
251002 Oceanografía química 251001 Oceanografía biológica |
spellingShingle |
251002 Oceanografía química 251001 Oceanografía biológica Hartmann, Jens Suitner, Niels Lim, Carl Schneider, Julieta Marín Samper, Laura Arístegui Ruiz, Javier Renforth, Phil Taucher, Jan Riebesell, Ulf Stability of alkalinity in ocean alkalinity enhancement (OAE) approaches -consequences for durability of CO2 storage |
topic_facet |
251002 Oceanografía química 251001 Oceanografía biológica |
description |
According to modelling studies, ocean alkalinity enhancement (OAE) is one of the proposed carbon dioxide removal (CDR) approaches with large potential, with the beneficial side effect of counteracting ocean acidification. The real-world application of OAE, however, remains unclear as most basic assumptions are untested. Before large-scale deployment can be considered, safe and sustainable procedures for the addition of alkalinity to seawater must be identified and governance established. One of the concerns is the stability of alkalinity when added to seawater. The surface ocean is already supersaturated with respect to calcite and aragonite, and an increase in total alkalinity (TA) together with a corresponding shift in carbonate chemistry towards higher carbonate ion concentrations would result in a further increase in supersaturation, and potentially to solid carbonate precipitation. Precipitation of carbonate minerals consumes alkalinity and increases dissolved CO2 in seawater, thereby reducing the efficiency of OAE for CO2 removal. In order to address the application of alkaline solution as well as fine particulate alkaline solids, a set of six experiments was performed using natural seawater with alkalinity of around 2400μmol kgsw-1. The application of CO2-equilibrated alkaline solution bears the lowest risk of losing alkalinity due to carbonate phase formation if added total alkalinity (δTA) is less than 2400μmol kgsw-1. The addition of reactive alkaline solids can cause a net loss of alkalinity if added δTA>600μmol kgsw-1 (e.g. for Mg(OH)2). Commercially available (ultrafine) Ca(OH)2 causes, in general, a net loss in TA for the tested amounts of TA addition, which has consequences for suggested use of slurries with alkaline solids supplied from ships. The rapid application of excessive amounts of Ca(OH)2, exceeding a threshold for alkalinity loss, resulted in a massive increase in TA (>20000μmol kgsw-1) at the cost of lower efficiency and resultant high pH values >9.5. Analysis of precipitates ... |
author2 |
orcid:0000-0003-1878-9321 orcid:0000-0003-3413-857X orcid:0000-0002-9035-4771 orcid:0000-0002-7271-717X #NODATA# orcid:0000-0002-9442-452X BU-BAS |
format |
Article in Journal/Newspaper |
author |
Hartmann, Jens Suitner, Niels Lim, Carl Schneider, Julieta Marín Samper, Laura Arístegui Ruiz, Javier Renforth, Phil Taucher, Jan Riebesell, Ulf |
author_facet |
Hartmann, Jens Suitner, Niels Lim, Carl Schneider, Julieta Marín Samper, Laura Arístegui Ruiz, Javier Renforth, Phil Taucher, Jan Riebesell, Ulf |
author_sort |
Hartmann, Jens |
title |
Stability of alkalinity in ocean alkalinity enhancement (OAE) approaches -consequences for durability of CO2 storage |
title_short |
Stability of alkalinity in ocean alkalinity enhancement (OAE) approaches -consequences for durability of CO2 storage |
title_full |
Stability of alkalinity in ocean alkalinity enhancement (OAE) approaches -consequences for durability of CO2 storage |
title_fullStr |
Stability of alkalinity in ocean alkalinity enhancement (OAE) approaches -consequences for durability of CO2 storage |
title_full_unstemmed |
Stability of alkalinity in ocean alkalinity enhancement (OAE) approaches -consequences for durability of CO2 storage |
title_sort |
stability of alkalinity in ocean alkalinity enhancement (oae) approaches -consequences for durability of co2 storage |
publishDate |
2023 |
url |
http://hdl.handle.net/10553/123136 https://doi.org/10.5194/bg-20-781-2023 |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_source |
Biogeosciences [ISSN 1726-4170], v. 20 (4), p. 781–802, (2023) |
op_relation |
Biogeosciences 20 1726-4170 http://hdl.handle.net/10553/123136 doi:10.5194/bg-20-781-2023 2-s2.0-85148762615 WOS:000936330500001 4 Sí |
op_doi |
https://doi.org/10.5194/bg-20-781-2023 |
container_title |
Biogeosciences |
container_volume |
20 |
container_issue |
4 |
container_start_page |
781 |
op_container_end_page |
802 |
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1769008468983808000 |