Understanding why the volume of suboxic waters does not increase over centuries of global warming in an Earth System Model
Global warming is expected to reduce oxygen solubility and vertical exchange in the ocean, changes which would be expected to result in an increase in the volume of hypoxic waters. A simulation made with a full Earth System model with dynamical atmosphere, ocean, sea ice and biogeochemical cycling (...
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2012
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ftdoajarticles:oai:doaj.org/article:a5b07f865f4347538a10c9c7d031b8c7 2023-05-15T18:18:33+02:00 Understanding why the volume of suboxic waters does not increase over centuries of global warming in an Earth System Model A. Gnanadesikan J. P. Dunne J. John 2012-03-01T00:00:00Z https://doi.org/10.5194/bg-9-1159-2012 https://doaj.org/article/a5b07f865f4347538a10c9c7d031b8c7 EN eng Copernicus Publications http://www.biogeosciences.net/9/1159/2012/bg-9-1159-2012.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-9-1159-2012 1726-4170 1726-4189 https://doaj.org/article/a5b07f865f4347538a10c9c7d031b8c7 Biogeosciences, Vol 9, Iss 3, Pp 1159-1172 (2012) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2012 ftdoajarticles https://doi.org/10.5194/bg-9-1159-2012 2022-12-31T03:30:06Z Global warming is expected to reduce oxygen solubility and vertical exchange in the ocean, changes which would be expected to result in an increase in the volume of hypoxic waters. A simulation made with a full Earth System model with dynamical atmosphere, ocean, sea ice and biogeochemical cycling (the Geophysical Fluid Dynamics Laboratory's Earth System Model 2.1) shows that this holds true if the condition for hypoxia is set relatively high. However, the volume of the most hypoxic (i.e., suboxic) waters does not increase under global warming, as these waters actually become more oxygenated. We show that the rise in dissolved oxygen in the tropical Pacific is associated with a drop in ventilation time. A term-by-term analysis within the least oxygenated waters shows an increased supply of dissolved oxygen due to lateral diffusion compensating an increase in remineralization within these highly hypoxic waters. This lateral diffusive flux is the result of an increase of ventilation along the Chilean coast, as a drying of the region under global warming opens up a region of wintertime convection in our model. The results highlight the potential sensitivity of suboxic waters to changes in subtropical ventilation as well as the importance of constraining lateral eddy transport of dissolved oxygen in such waters. Article in Journal/Newspaper Sea ice Directory of Open Access Journals: DOAJ Articles Pacific Biogeosciences 9 3 1159 1172 |
institution |
Open Polar |
collection |
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 A. Gnanadesikan J. P. Dunne J. John Understanding why the volume of suboxic waters does not increase over centuries of global warming in an Earth System Model |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
Global warming is expected to reduce oxygen solubility and vertical exchange in the ocean, changes which would be expected to result in an increase in the volume of hypoxic waters. A simulation made with a full Earth System model with dynamical atmosphere, ocean, sea ice and biogeochemical cycling (the Geophysical Fluid Dynamics Laboratory's Earth System Model 2.1) shows that this holds true if the condition for hypoxia is set relatively high. However, the volume of the most hypoxic (i.e., suboxic) waters does not increase under global warming, as these waters actually become more oxygenated. We show that the rise in dissolved oxygen in the tropical Pacific is associated with a drop in ventilation time. A term-by-term analysis within the least oxygenated waters shows an increased supply of dissolved oxygen due to lateral diffusion compensating an increase in remineralization within these highly hypoxic waters. This lateral diffusive flux is the result of an increase of ventilation along the Chilean coast, as a drying of the region under global warming opens up a region of wintertime convection in our model. The results highlight the potential sensitivity of suboxic waters to changes in subtropical ventilation as well as the importance of constraining lateral eddy transport of dissolved oxygen in such waters. |
format |
Article in Journal/Newspaper |
author |
A. Gnanadesikan J. P. Dunne J. John |
author_facet |
A. Gnanadesikan J. P. Dunne J. John |
author_sort |
A. Gnanadesikan |
title |
Understanding why the volume of suboxic waters does not increase over centuries of global warming in an Earth System Model |
title_short |
Understanding why the volume of suboxic waters does not increase over centuries of global warming in an Earth System Model |
title_full |
Understanding why the volume of suboxic waters does not increase over centuries of global warming in an Earth System Model |
title_fullStr |
Understanding why the volume of suboxic waters does not increase over centuries of global warming in an Earth System Model |
title_full_unstemmed |
Understanding why the volume of suboxic waters does not increase over centuries of global warming in an Earth System Model |
title_sort |
understanding why the volume of suboxic waters does not increase over centuries of global warming in an earth system model |
publisher |
Copernicus Publications |
publishDate |
2012 |
url |
https://doi.org/10.5194/bg-9-1159-2012 https://doaj.org/article/a5b07f865f4347538a10c9c7d031b8c7 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
Biogeosciences, Vol 9, Iss 3, Pp 1159-1172 (2012) |
op_relation |
http://www.biogeosciences.net/9/1159/2012/bg-9-1159-2012.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-9-1159-2012 1726-4170 1726-4189 https://doaj.org/article/a5b07f865f4347538a10c9c7d031b8c7 |
op_doi |
https://doi.org/10.5194/bg-9-1159-2012 |
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Biogeosciences |
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9 |
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3 |
container_start_page |
1159 |
op_container_end_page |
1172 |
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