An assessment of ocean margin anaerobic processes on oceanic alkalinity budget
Recent interest in the ocean’s capacity to absorb atmospheric CO2 and buffer the accompanying “ocean acidification” has prompted discussions on the magnitude of ocean margin alkalinity production via anaerobic processes. However, available estimates are largely based on gross reaction rates or misco...
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fttexasamucorpus:oai:tamucc-ir.tdl.org:1969.6/95728 2023-10-25T01:42:27+02:00 An assessment of ocean margin anaerobic processes on oceanic alkalinity budget Hu, Xinping Cai, Wei-Jun 2011-07-08 application/pdf https://hdl.handle.net/1969.6/95728 en_US eng Global Biogeochem Hu, X. and Cai, W.-J., 2011. An assessment of ocean margin anaerobic processes on oceanic alkalinity budget. Global Biogeochemical Cycles, GB3003, doi:10.1029/2010GB003859 https://hdl.handle.net/1969.6/95728 Article 2011 fttexasamucorpus https://doi.org/10.1029/2010GB003859 2023-09-25T10:20:01Z Recent interest in the ocean’s capacity to absorb atmospheric CO2 and buffer the accompanying “ocean acidification” has prompted discussions on the magnitude of ocean margin alkalinity production via anaerobic processes. However, available estimates are largely based on gross reaction rates or misconceptions regarding reaction stoichiometry. In this paper, we argue that net alkalinity gain does not result from the internal cycling of nitrogen and sulfur species or from the reduction of metal oxides. Instead, only the processes that involve permanent loss of anaerobic remineralization products, i.e., nitrogen gas from net denitrification and reduced sulfur (i.e., pyrite burial) from net sulfate reduction, could contribute to this anaerobic alkalinity production. Our revised estimate of net alkalinity production from anaerobic processes is on the order of 4–5 Tmol yr−1 in global ocean margins that include both continental shelves and oxygen minimum zones, significantly smaller than the previously estimated rate of 16–31 Tmol yr−1 . In addition, pyrite burial in coastal habitats (salt marshes, mangroves, and seagrass meadows) may contribute another 0.1–1.1 Tmol yr−1 , although their long‐term effect is not yet clear under current changing climate conditions and rising sea levels. Finally, we propose that these alkalinity production reactions can be viewed as “charge transfer” processes, in which negative charges of nitrate and sulfate ions are converted to those of bicarbonate along with a net loss of these oxidative anions. Article in Journal/Newspaper Ocean acidification Texas A&M University - Corpus Christi: DSpace Repository Global Biogeochemical Cycles 25 3 n/a n/a |
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Texas A&M University - Corpus Christi: DSpace Repository |
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English |
description |
Recent interest in the ocean’s capacity to absorb atmospheric CO2 and buffer the accompanying “ocean acidification” has prompted discussions on the magnitude of ocean margin alkalinity production via anaerobic processes. However, available estimates are largely based on gross reaction rates or misconceptions regarding reaction stoichiometry. In this paper, we argue that net alkalinity gain does not result from the internal cycling of nitrogen and sulfur species or from the reduction of metal oxides. Instead, only the processes that involve permanent loss of anaerobic remineralization products, i.e., nitrogen gas from net denitrification and reduced sulfur (i.e., pyrite burial) from net sulfate reduction, could contribute to this anaerobic alkalinity production. Our revised estimate of net alkalinity production from anaerobic processes is on the order of 4–5 Tmol yr−1 in global ocean margins that include both continental shelves and oxygen minimum zones, significantly smaller than the previously estimated rate of 16–31 Tmol yr−1 . In addition, pyrite burial in coastal habitats (salt marshes, mangroves, and seagrass meadows) may contribute another 0.1–1.1 Tmol yr−1 , although their long‐term effect is not yet clear under current changing climate conditions and rising sea levels. Finally, we propose that these alkalinity production reactions can be viewed as “charge transfer” processes, in which negative charges of nitrate and sulfate ions are converted to those of bicarbonate along with a net loss of these oxidative anions. |
format |
Article in Journal/Newspaper |
author |
Hu, Xinping Cai, Wei-Jun |
spellingShingle |
Hu, Xinping Cai, Wei-Jun An assessment of ocean margin anaerobic processes on oceanic alkalinity budget |
author_facet |
Hu, Xinping Cai, Wei-Jun |
author_sort |
Hu, Xinping |
title |
An assessment of ocean margin anaerobic processes on oceanic alkalinity budget |
title_short |
An assessment of ocean margin anaerobic processes on oceanic alkalinity budget |
title_full |
An assessment of ocean margin anaerobic processes on oceanic alkalinity budget |
title_fullStr |
An assessment of ocean margin anaerobic processes on oceanic alkalinity budget |
title_full_unstemmed |
An assessment of ocean margin anaerobic processes on oceanic alkalinity budget |
title_sort |
assessment of ocean margin anaerobic processes on oceanic alkalinity budget |
publisher |
Global Biogeochem |
publishDate |
2011 |
url |
https://hdl.handle.net/1969.6/95728 |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_relation |
Hu, X. and Cai, W.-J., 2011. An assessment of ocean margin anaerobic processes on oceanic alkalinity budget. Global Biogeochemical Cycles, GB3003, doi:10.1029/2010GB003859 https://hdl.handle.net/1969.6/95728 |
op_doi |
https://doi.org/10.1029/2010GB003859 |
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Global Biogeochemical Cycles |
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25 |
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3 |
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1780739020020514816 |