Dynamics of inorganic carbon and pH in a large subtropical continental shelf system: Interaction between eutrophication, hypoxia, and ocean acidification
Abstract We examined the dynamics of dissolved inorganic carbon (DIC) and pH in the Pearl River Estuary (PRE) and the adjacent northern South China Sea (NSCS) shelf in summer, aiming for a better understanding of the interaction between eutrophication, hypoxia, and ocean acidification. Using a semi‐...
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crwiley:10.1002/lno.11393 2024-06-23T07:55:48+00:00 Dynamics of inorganic carbon and pH in a large subtropical continental shelf system: Interaction between eutrophication, hypoxia, and ocean acidification Zhao, Yangyang Liu, Jing Uthaipan, Khanittha Song, Xue Xu, Yi He, Biyan Liu, Hongbin Gan, Jianping Dai, Minhan the National Key Scientific Research Project the University Grants Committee of Hong Kong 2020 http://dx.doi.org/10.1002/lno.11393 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Flno.11393 https://onlinelibrary.wiley.com/doi/pdf/10.1002/lno.11393 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/lno.11393 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.1002/lno.11393 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Limnology and Oceanography volume 65, issue 6, page 1359-1379 ISSN 0024-3590 1939-5590 journal-article 2020 crwiley https://doi.org/10.1002/lno.11393 2024-06-13T04:21:15Z Abstract We examined the dynamics of dissolved inorganic carbon (DIC) and pH in the Pearl River Estuary (PRE) and the adjacent northern South China Sea (NSCS) shelf in summer, aiming for a better understanding of the interaction between eutrophication, hypoxia, and ocean acidification. Using a semi‐analytical diagnostic approach based on validated multiple end‐member water mass mixing models, we showed a −191 ± 54 μ mol kg −1 deficit in DIC concentrations in an extensive surface plume bulge, corresponding to a significant pH increase of ∼ 0.57 ± 0.19 units relative to conservative mixing. In contrast, DIC additions in the bottom hypoxic zone reached ∼ 139 ± 21 μ mol kg −1 , accompanied by a decrease in pH of −0.30 ± 0.04 units. In combination with stable carbon isotopic compositions, we found biological production and CO 2 outgassing to be responsible for DIC deficits in surface waters, while degradation of organic matter (OM) accounted for DIC additions in bottom waters. The PRE‐NSCS plume system as a whole served as a net source of atmospheric CO 2 from the perspective of Lagrangian observations, because strong CO 2 outgassing in the inner estuary overwhelmed the CO 2 uptake in the plume despite strong phytoplankton blooms. Using a two‐layer box model, we further estimated that at least ∼ 45 ± 13% of eutrophication‐driven OM production in the surface plume accounted for 67 ± 18% of the DIC addition and oxygen consumption in bottom waters. Eutrophication also buffered ocean acidification in surface waters while hypoxia enhanced it in bottom waters, but their effects on acid‐base buffering capacity were secondary to the amplification of coastal ocean acidification caused by freshwater inputs. Article in Journal/Newspaper Ocean acidification Wiley Online Library Limnology and Oceanography 65 6 1359 1379 |
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English |
description |
Abstract We examined the dynamics of dissolved inorganic carbon (DIC) and pH in the Pearl River Estuary (PRE) and the adjacent northern South China Sea (NSCS) shelf in summer, aiming for a better understanding of the interaction between eutrophication, hypoxia, and ocean acidification. Using a semi‐analytical diagnostic approach based on validated multiple end‐member water mass mixing models, we showed a −191 ± 54 μ mol kg −1 deficit in DIC concentrations in an extensive surface plume bulge, corresponding to a significant pH increase of ∼ 0.57 ± 0.19 units relative to conservative mixing. In contrast, DIC additions in the bottom hypoxic zone reached ∼ 139 ± 21 μ mol kg −1 , accompanied by a decrease in pH of −0.30 ± 0.04 units. In combination with stable carbon isotopic compositions, we found biological production and CO 2 outgassing to be responsible for DIC deficits in surface waters, while degradation of organic matter (OM) accounted for DIC additions in bottom waters. The PRE‐NSCS plume system as a whole served as a net source of atmospheric CO 2 from the perspective of Lagrangian observations, because strong CO 2 outgassing in the inner estuary overwhelmed the CO 2 uptake in the plume despite strong phytoplankton blooms. Using a two‐layer box model, we further estimated that at least ∼ 45 ± 13% of eutrophication‐driven OM production in the surface plume accounted for 67 ± 18% of the DIC addition and oxygen consumption in bottom waters. Eutrophication also buffered ocean acidification in surface waters while hypoxia enhanced it in bottom waters, but their effects on acid‐base buffering capacity were secondary to the amplification of coastal ocean acidification caused by freshwater inputs. |
author2 |
the National Key Scientific Research Project the University Grants Committee of Hong Kong |
format |
Article in Journal/Newspaper |
author |
Zhao, Yangyang Liu, Jing Uthaipan, Khanittha Song, Xue Xu, Yi He, Biyan Liu, Hongbin Gan, Jianping Dai, Minhan |
spellingShingle |
Zhao, Yangyang Liu, Jing Uthaipan, Khanittha Song, Xue Xu, Yi He, Biyan Liu, Hongbin Gan, Jianping Dai, Minhan Dynamics of inorganic carbon and pH in a large subtropical continental shelf system: Interaction between eutrophication, hypoxia, and ocean acidification |
author_facet |
Zhao, Yangyang Liu, Jing Uthaipan, Khanittha Song, Xue Xu, Yi He, Biyan Liu, Hongbin Gan, Jianping Dai, Minhan |
author_sort |
Zhao, Yangyang |
title |
Dynamics of inorganic carbon and pH in a large subtropical continental shelf system: Interaction between eutrophication, hypoxia, and ocean acidification |
title_short |
Dynamics of inorganic carbon and pH in a large subtropical continental shelf system: Interaction between eutrophication, hypoxia, and ocean acidification |
title_full |
Dynamics of inorganic carbon and pH in a large subtropical continental shelf system: Interaction between eutrophication, hypoxia, and ocean acidification |
title_fullStr |
Dynamics of inorganic carbon and pH in a large subtropical continental shelf system: Interaction between eutrophication, hypoxia, and ocean acidification |
title_full_unstemmed |
Dynamics of inorganic carbon and pH in a large subtropical continental shelf system: Interaction between eutrophication, hypoxia, and ocean acidification |
title_sort |
dynamics of inorganic carbon and ph in a large subtropical continental shelf system: interaction between eutrophication, hypoxia, and ocean acidification |
publisher |
Wiley |
publishDate |
2020 |
url |
http://dx.doi.org/10.1002/lno.11393 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Flno.11393 https://onlinelibrary.wiley.com/doi/pdf/10.1002/lno.11393 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/lno.11393 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.1002/lno.11393 |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_source |
Limnology and Oceanography volume 65, issue 6, page 1359-1379 ISSN 0024-3590 1939-5590 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/lno.11393 |
container_title |
Limnology and Oceanography |
container_volume |
65 |
container_issue |
6 |
container_start_page |
1359 |
op_container_end_page |
1379 |
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1802648514849669120 |