Does ocean acidification induce an upward flux of marine aggregates?
The absorption of anthropogenic atmospheric carbon dioxide (CO 2 ) by the ocean provokes its acidification. This acidification may alter several oceanic processes, including the export of biogenic carbon from the upper layer of the ocean, hence providing a feedback on rising atmospheric carbon conce...
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ftcopernicus:oai:publications.copernicus.org:bg6007 2023-05-15T17:50:33+02:00 Does ocean acidification induce an upward flux of marine aggregates? Mari, X. 2018-09-27 application/pdf https://doi.org/10.5194/bg-5-1023-2008 https://www.biogeosciences.net/5/1023/2008/ eng eng doi:10.5194/bg-5-1023-2008 https://www.biogeosciences.net/5/1023/2008/ eISSN: 1726-4189 Text 2018 ftcopernicus https://doi.org/10.5194/bg-5-1023-2008 2019-12-24T09:58:14Z The absorption of anthropogenic atmospheric carbon dioxide (CO 2 ) by the ocean provokes its acidification. This acidification may alter several oceanic processes, including the export of biogenic carbon from the upper layer of the ocean, hence providing a feedback on rising atmospheric carbon concentrations. The effect of seawater acidification on transparent exopolymeric particles (TEP) driven aggregation and sedimentation processes were investigated by studying the interactions between latex beads and TEP precursors collected in the lagoon of New Caledonia. A suspension of TEP and beads was prepared and the formation of mixed aggregates was monitored as a function of pH under increasing turbulence intensities. The pH was controlled by addition of sulfuric acid. Aggregation and sedimentation processes driven by TEP were drastically reduced when the pH of seawater decreases within the expected limits imposed by increased anthropogenic CO 2 emissions. In addition to the diminution of TEP sticking properties, the diminution of seawater pH led to a significant increase of the TEP pool, most likely due to swollen structures. A diminution of seawater pH by 0.2 units or more led to a stop or a reversal of the downward flux of particles. If applicable to oceanic conditions, the sedimentation of marine aggregates may slow down or even stop as the pH decreases, and the vertical flux of organic carbon may reverse. This would enhance both rising atmospheric carbon and ocean acidification. Text Ocean acidification Copernicus Publications: E-Journals Biogeosciences 5 4 1023 1031 |
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Copernicus Publications: E-Journals |
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English |
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The absorption of anthropogenic atmospheric carbon dioxide (CO 2 ) by the ocean provokes its acidification. This acidification may alter several oceanic processes, including the export of biogenic carbon from the upper layer of the ocean, hence providing a feedback on rising atmospheric carbon concentrations. The effect of seawater acidification on transparent exopolymeric particles (TEP) driven aggregation and sedimentation processes were investigated by studying the interactions between latex beads and TEP precursors collected in the lagoon of New Caledonia. A suspension of TEP and beads was prepared and the formation of mixed aggregates was monitored as a function of pH under increasing turbulence intensities. The pH was controlled by addition of sulfuric acid. Aggregation and sedimentation processes driven by TEP were drastically reduced when the pH of seawater decreases within the expected limits imposed by increased anthropogenic CO 2 emissions. In addition to the diminution of TEP sticking properties, the diminution of seawater pH led to a significant increase of the TEP pool, most likely due to swollen structures. A diminution of seawater pH by 0.2 units or more led to a stop or a reversal of the downward flux of particles. If applicable to oceanic conditions, the sedimentation of marine aggregates may slow down or even stop as the pH decreases, and the vertical flux of organic carbon may reverse. This would enhance both rising atmospheric carbon and ocean acidification. |
format |
Text |
author |
Mari, X. |
spellingShingle |
Mari, X. Does ocean acidification induce an upward flux of marine aggregates? |
author_facet |
Mari, X. |
author_sort |
Mari, X. |
title |
Does ocean acidification induce an upward flux of marine aggregates? |
title_short |
Does ocean acidification induce an upward flux of marine aggregates? |
title_full |
Does ocean acidification induce an upward flux of marine aggregates? |
title_fullStr |
Does ocean acidification induce an upward flux of marine aggregates? |
title_full_unstemmed |
Does ocean acidification induce an upward flux of marine aggregates? |
title_sort |
does ocean acidification induce an upward flux of marine aggregates? |
publishDate |
2018 |
url |
https://doi.org/10.5194/bg-5-1023-2008 https://www.biogeosciences.net/5/1023/2008/ |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-5-1023-2008 https://www.biogeosciences.net/5/1023/2008/ |
op_doi |
https://doi.org/10.5194/bg-5-1023-2008 |
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Biogeosciences |
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5 |
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4 |
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1023 |
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1031 |
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1766157366678519808 |