Hydrogeochemistry and Acidic Property of Submarine Groundwater Discharge Around Two Coral Islands in the Northern South China Sea
Submarine groundwater discharge (SGD) is an important source of nutrients in many coastal regions, yet little information is available on its carbonate chemistry and controlling factors. This study examined the processes and factors controlling the hydrogeochemistry and acidic property of the ground...
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ftdoajarticles:oai:doaj.org/article:41937ac794204a59837ab72759978c4d 2023-05-15T17:52:07+02:00 Hydrogeochemistry and Acidic Property of Submarine Groundwater Discharge Around Two Coral Islands in the Northern South China Sea Hon-Kit Lui Min-Yun Liu Hsiu-Chin Lin Hsiao-Chun Tseng Li-Lian Liu Feng-Yu Wang Wei-Ping Hou Rae Chang Chen-Tung Arthur Chen 2021-09-01T00:00:00Z https://doi.org/10.3389/feart.2021.697388 https://doaj.org/article/41937ac794204a59837ab72759978c4d EN eng Frontiers Media S.A. https://www.frontiersin.org/articles/10.3389/feart.2021.697388/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2021.697388 https://doaj.org/article/41937ac794204a59837ab72759978c4d Frontiers in Earth Science, Vol 9 (2021) Dongsha Liuqiu ocean acidifcation pH saturation state of CaCO chemical weathering geochemistry Science Q article 2021 ftdoajarticles https://doi.org/10.3389/feart.2021.697388 2022-12-31T07:09:05Z Submarine groundwater discharge (SGD) is an important source of nutrients in many coastal regions, yet little information is available on its carbonate chemistry and controlling factors. This study examined the processes and factors controlling the hydrogeochemistry and acidic property of the groundwaters and SGD waters of two isolated coral islands, Liuqiu Island (13 km off southwestern Taiwan) and Dongsha Island (located in the northern South China Sea, 420 km away from Liuqiu Island). Our results showed that the total alkalinity and dissolved inorganic carbon (DIC) of the fresh SGD waters were controlled mainly by the chemical weathering of carbonate minerals. Part of the DIC came from the organic matter decomposition or soil CO2, reducing the pH and CO32− concentration. Distributions of the carbonate chemistry and nutrients of the SGD waters were controlled mainly by physical mixing between the groundwater and the ambient seawater under the seabed, the so-called subterranean estuary. The Ca2+ released through weathering significantly increased the saturation state of aragonite or calcite, reducing the corrosiveness of the SGD waters on the carbonate rocks. This study is likely the first to examine the effects of the acidic property of SGD waters on the biogenic carbonate spine of a sea urchin and a pteropod shell. The spring water with similar carbonate chemistry to that of the freshwater SGD endmember from Liuqiu Island with a saturation state of aragonite of 0.96 caused observable dissolution on the spine of a sea urchin and a pteropod shell, but the spine dissolved more readily. This was because the spine is made of high-Mg calcite, which has higher solubility than that of aragonite or calcite. Such a result implies that some marine organisms with carbonate skeletons or shells containing high Mg:Ca ratios may suffer the impact of ocean acidification earlier. Although the SGD may contribute less than 10% of freshwater discharge by rivers to the coastal area, its impact on coastal biogeochemical cycles and ... Article in Journal/Newspaper Ocean acidification Directory of Open Access Journals: DOAJ Articles Frontiers in Earth Science 9 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Dongsha Liuqiu ocean acidifcation pH saturation state of CaCO chemical weathering geochemistry Science Q |
spellingShingle |
Dongsha Liuqiu ocean acidifcation pH saturation state of CaCO chemical weathering geochemistry Science Q Hon-Kit Lui Min-Yun Liu Hsiu-Chin Lin Hsiao-Chun Tseng Li-Lian Liu Feng-Yu Wang Wei-Ping Hou Rae Chang Chen-Tung Arthur Chen Hydrogeochemistry and Acidic Property of Submarine Groundwater Discharge Around Two Coral Islands in the Northern South China Sea |
topic_facet |
Dongsha Liuqiu ocean acidifcation pH saturation state of CaCO chemical weathering geochemistry Science Q |
description |
Submarine groundwater discharge (SGD) is an important source of nutrients in many coastal regions, yet little information is available on its carbonate chemistry and controlling factors. This study examined the processes and factors controlling the hydrogeochemistry and acidic property of the groundwaters and SGD waters of two isolated coral islands, Liuqiu Island (13 km off southwestern Taiwan) and Dongsha Island (located in the northern South China Sea, 420 km away from Liuqiu Island). Our results showed that the total alkalinity and dissolved inorganic carbon (DIC) of the fresh SGD waters were controlled mainly by the chemical weathering of carbonate minerals. Part of the DIC came from the organic matter decomposition or soil CO2, reducing the pH and CO32− concentration. Distributions of the carbonate chemistry and nutrients of the SGD waters were controlled mainly by physical mixing between the groundwater and the ambient seawater under the seabed, the so-called subterranean estuary. The Ca2+ released through weathering significantly increased the saturation state of aragonite or calcite, reducing the corrosiveness of the SGD waters on the carbonate rocks. This study is likely the first to examine the effects of the acidic property of SGD waters on the biogenic carbonate spine of a sea urchin and a pteropod shell. The spring water with similar carbonate chemistry to that of the freshwater SGD endmember from Liuqiu Island with a saturation state of aragonite of 0.96 caused observable dissolution on the spine of a sea urchin and a pteropod shell, but the spine dissolved more readily. This was because the spine is made of high-Mg calcite, which has higher solubility than that of aragonite or calcite. Such a result implies that some marine organisms with carbonate skeletons or shells containing high Mg:Ca ratios may suffer the impact of ocean acidification earlier. Although the SGD may contribute less than 10% of freshwater discharge by rivers to the coastal area, its impact on coastal biogeochemical cycles and ... |
format |
Article in Journal/Newspaper |
author |
Hon-Kit Lui Min-Yun Liu Hsiu-Chin Lin Hsiao-Chun Tseng Li-Lian Liu Feng-Yu Wang Wei-Ping Hou Rae Chang Chen-Tung Arthur Chen |
author_facet |
Hon-Kit Lui Min-Yun Liu Hsiu-Chin Lin Hsiao-Chun Tseng Li-Lian Liu Feng-Yu Wang Wei-Ping Hou Rae Chang Chen-Tung Arthur Chen |
author_sort |
Hon-Kit Lui |
title |
Hydrogeochemistry and Acidic Property of Submarine Groundwater Discharge Around Two Coral Islands in the Northern South China Sea |
title_short |
Hydrogeochemistry and Acidic Property of Submarine Groundwater Discharge Around Two Coral Islands in the Northern South China Sea |
title_full |
Hydrogeochemistry and Acidic Property of Submarine Groundwater Discharge Around Two Coral Islands in the Northern South China Sea |
title_fullStr |
Hydrogeochemistry and Acidic Property of Submarine Groundwater Discharge Around Two Coral Islands in the Northern South China Sea |
title_full_unstemmed |
Hydrogeochemistry and Acidic Property of Submarine Groundwater Discharge Around Two Coral Islands in the Northern South China Sea |
title_sort |
hydrogeochemistry and acidic property of submarine groundwater discharge around two coral islands in the northern south china sea |
publisher |
Frontiers Media S.A. |
publishDate |
2021 |
url |
https://doi.org/10.3389/feart.2021.697388 https://doaj.org/article/41937ac794204a59837ab72759978c4d |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_source |
Frontiers in Earth Science, Vol 9 (2021) |
op_relation |
https://www.frontiersin.org/articles/10.3389/feart.2021.697388/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2021.697388 https://doaj.org/article/41937ac794204a59837ab72759978c4d |
op_doi |
https://doi.org/10.3389/feart.2021.697388 |
container_title |
Frontiers in Earth Science |
container_volume |
9 |
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1766159471843737600 |