Considerations for hypothetical carbon dioxide removal via alkalinity addition in the Amazon River watershed
The Amazon River plume plays a critical role in shaping the carbonate chemistry over a vast area in the western tropical North Atlantic. We conduct a sensitivity analysis of hypothetical ocean alkalinity enhancement (OAE) via quicklime addition in the Amazon River watershed, examining the response o...
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ftdoajarticles:oai:doaj.org/article:6bbef6cd9eaa44c4aee665aa684d2376 2023-06-11T04:15:05+02:00 Considerations for hypothetical carbon dioxide removal via alkalinity addition in the Amazon River watershed L. Mu J. B. Palter H. Wang 2023-05-01T00:00:00Z https://doi.org/10.5194/bg-20-1963-2023 https://doaj.org/article/6bbef6cd9eaa44c4aee665aa684d2376 EN eng Copernicus Publications https://bg.copernicus.org/articles/20/1963/2023/bg-20-1963-2023.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-20-1963-2023 1726-4170 1726-4189 https://doaj.org/article/6bbef6cd9eaa44c4aee665aa684d2376 Biogeosciences, Vol 20, Pp 1963-1977 (2023) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2023 ftdoajarticles https://doi.org/10.5194/bg-20-1963-2023 2023-05-28T00:35:19Z The Amazon River plume plays a critical role in shaping the carbonate chemistry over a vast area in the western tropical North Atlantic. We conduct a sensitivity analysis of hypothetical ocean alkalinity enhancement (OAE) via quicklime addition in the Amazon River watershed, examining the response of carbonate chemistry and air–sea carbon dioxide flux to the alkalinity addition. Through a series of sensitivity tests, we show that the detectability of the OAE-induced alkalinity increment depends on the perturbation strength (or size of the alkalinity addition, ΔTA ) and the number of samples: there is a 90 % chance to meet a minimum detectability requirement with ΔTA>15 µmol kg −1 and sample size >40 , given background variability of 15–30 µmol kg −1 . OAE-induced p CO 2 reduction at the Amazon plume surface would range between 0–25 µatm when ΔTA=20 µmol kg −1 , decreasing with increasing salinity ( S ). Adding 20 µmol kg −1 of alkalinity at the river mouth could elevate the total carbon uptake in the Amazon River plume ( 15 < S < 35 <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="59pt" height="10pt" class="svg-formula" dspmath="mathimg" md5hash="0aef546cad9c3e9dc5cd859dec5d81a5"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-20-1963-2023-ie00001.svg" width="59pt" height="10pt" src="bg-20-1963-2023-ie00001.png"/></svg:svg> ) by at least 0.07–0.1 Mt CO 2 per month , and a major portion of the uptake would occur in the saltiest region ( S >32 ) due to its large size, comprising approximately 80 % of the S >15 plume area. However, the lowest-salinity region ( S <15 ) has a greater drop in surface ocean partial pressure of CO 2 ( p CO 2 sw ) due to its low buffer capacity, potentially allowing for observational detectability of p CO 2 sw reduction in this region. Reduced outgassing in this part of the plume, while more uncertain, may also be important for total additional CO 2 uptake. Such sensitivity tests are useful in designing minimalistic field ... Article in Journal/Newspaper North Atlantic Directory of Open Access Journals: DOAJ Articles Biogeosciences 20 10 1963 1977 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
spellingShingle |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 L. Mu J. B. Palter H. Wang Considerations for hypothetical carbon dioxide removal via alkalinity addition in the Amazon River watershed |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
The Amazon River plume plays a critical role in shaping the carbonate chemistry over a vast area in the western tropical North Atlantic. We conduct a sensitivity analysis of hypothetical ocean alkalinity enhancement (OAE) via quicklime addition in the Amazon River watershed, examining the response of carbonate chemistry and air–sea carbon dioxide flux to the alkalinity addition. Through a series of sensitivity tests, we show that the detectability of the OAE-induced alkalinity increment depends on the perturbation strength (or size of the alkalinity addition, ΔTA ) and the number of samples: there is a 90 % chance to meet a minimum detectability requirement with ΔTA>15 µmol kg −1 and sample size >40 , given background variability of 15–30 µmol kg −1 . OAE-induced p CO 2 reduction at the Amazon plume surface would range between 0–25 µatm when ΔTA=20 µmol kg −1 , decreasing with increasing salinity ( S ). Adding 20 µmol kg −1 of alkalinity at the river mouth could elevate the total carbon uptake in the Amazon River plume ( 15 < S < 35 <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="59pt" height="10pt" class="svg-formula" dspmath="mathimg" md5hash="0aef546cad9c3e9dc5cd859dec5d81a5"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-20-1963-2023-ie00001.svg" width="59pt" height="10pt" src="bg-20-1963-2023-ie00001.png"/></svg:svg> ) by at least 0.07–0.1 Mt CO 2 per month , and a major portion of the uptake would occur in the saltiest region ( S >32 ) due to its large size, comprising approximately 80 % of the S >15 plume area. However, the lowest-salinity region ( S <15 ) has a greater drop in surface ocean partial pressure of CO 2 ( p CO 2 sw ) due to its low buffer capacity, potentially allowing for observational detectability of p CO 2 sw reduction in this region. Reduced outgassing in this part of the plume, while more uncertain, may also be important for total additional CO 2 uptake. Such sensitivity tests are useful in designing minimalistic field ... |
format |
Article in Journal/Newspaper |
author |
L. Mu J. B. Palter H. Wang |
author_facet |
L. Mu J. B. Palter H. Wang |
author_sort |
L. Mu |
title |
Considerations for hypothetical carbon dioxide removal via alkalinity addition in the Amazon River watershed |
title_short |
Considerations for hypothetical carbon dioxide removal via alkalinity addition in the Amazon River watershed |
title_full |
Considerations for hypothetical carbon dioxide removal via alkalinity addition in the Amazon River watershed |
title_fullStr |
Considerations for hypothetical carbon dioxide removal via alkalinity addition in the Amazon River watershed |
title_full_unstemmed |
Considerations for hypothetical carbon dioxide removal via alkalinity addition in the Amazon River watershed |
title_sort |
considerations for hypothetical carbon dioxide removal via alkalinity addition in the amazon river watershed |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://doi.org/10.5194/bg-20-1963-2023 https://doaj.org/article/6bbef6cd9eaa44c4aee665aa684d2376 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Biogeosciences, Vol 20, Pp 1963-1977 (2023) |
op_relation |
https://bg.copernicus.org/articles/20/1963/2023/bg-20-1963-2023.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-20-1963-2023 1726-4170 1726-4189 https://doaj.org/article/6bbef6cd9eaa44c4aee665aa684d2376 |
op_doi |
https://doi.org/10.5194/bg-20-1963-2023 |
container_title |
Biogeosciences |
container_volume |
20 |
container_issue |
10 |
container_start_page |
1963 |
op_container_end_page |
1977 |
_version_ |
1768371616370130944 |