Combined Effects of Atmospheric and Seafloor Iron Fluxes to the Glacial Ocean
Changes in the ocean iron cycle could help explain the low atmospheric CO2 during the Last Glacial Maximum (LGM). Previous modeling studies have mostly considered changes in aeolian iron fluxes, although it is known that sedimentary and hydrothermal fluxes are important iron sources for today's...
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AGU (American Geophysical Union)
2017
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ftoceanrep:oai:oceanrep.geomar.de:40276 2023-12-10T09:53:59+01:00 Combined Effects of Atmospheric and Seafloor Iron Fluxes to the Glacial Ocean Muglia, Juan Somes, Christopher J. Nickelsen, Levin Schmittner, Andreas 2017-11-11 text https://oceanrep.geomar.de/id/eprint/40276/ https://oceanrep.geomar.de/id/eprint/40276/7/Muglia_et_al-2017-Paleoceanography.pdf https://doi.org/10.1002/2016PA003077 en eng AGU (American Geophysical Union) Wiley https://oceanrep.geomar.de/id/eprint/40276/7/Muglia_et_al-2017-Paleoceanography.pdf Muglia, J., Somes, C. J. , Nickelsen, L. and Schmittner, A. (2017) Combined Effects of Atmospheric and Seafloor Iron Fluxes to the Glacial Ocean. Open Access Paleoceanography, 32 (11). pp. 1204-1218. DOI 10.1002/2016PA003077 <https://doi.org/10.1002/2016PA003077>. doi:10.1002/2016PA003077 info:eu-repo/semantics/openAccess Article PeerReviewed 2017 ftoceanrep https://doi.org/10.1002/2016PA003077 2023-11-13T00:22:56Z Changes in the ocean iron cycle could help explain the low atmospheric CO2 during the Last Glacial Maximum (LGM). Previous modeling studies have mostly considered changes in aeolian iron fluxes, although it is known that sedimentary and hydrothermal fluxes are important iron sources for today's ocean. Here we explore effects of preindustrial-to-LGM changes in atmospheric dust, sedimentary, and hydrothermal fluxes on the ocean's iron and carbon cycles in a global coupled biogeochemical-circulation model. Considering variable atmospheric iron solubility decreases LGM surface soluble iron fluxes compared with assuming constant solubility. This limits potential increases in productivity and export production due to surface iron fertilization, lowering atmospheric CO2 by only 4 ppm. The effect is countered by a decrease in sedimentary flux due to lower sea level, which increases CO2 by 15 ppm. Assuming a 10 times higher iron dust solubility in the Southern Ocean, combined with changes in sedimentary flux, we obtain an atmospheric CO2 reduction of 13 ppm. The high uncertainty in the iron fluxes does not allow us to determine the net direction and magnitude of variations in atmospheric CO2 due to changes in the iron cycle. Our model does not account for changes to iron-binding ligand concentrations that could modify the results. We conclude that when evaluating glacial-interglacial changes in the ocean iron cycle, not only surface but also seafloor fluxes must be taken into account. Article in Journal/Newspaper Southern Ocean OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Southern Ocean Paleoceanography 32 11 1204 1218 |
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Open Polar |
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OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
language |
English |
description |
Changes in the ocean iron cycle could help explain the low atmospheric CO2 during the Last Glacial Maximum (LGM). Previous modeling studies have mostly considered changes in aeolian iron fluxes, although it is known that sedimentary and hydrothermal fluxes are important iron sources for today's ocean. Here we explore effects of preindustrial-to-LGM changes in atmospheric dust, sedimentary, and hydrothermal fluxes on the ocean's iron and carbon cycles in a global coupled biogeochemical-circulation model. Considering variable atmospheric iron solubility decreases LGM surface soluble iron fluxes compared with assuming constant solubility. This limits potential increases in productivity and export production due to surface iron fertilization, lowering atmospheric CO2 by only 4 ppm. The effect is countered by a decrease in sedimentary flux due to lower sea level, which increases CO2 by 15 ppm. Assuming a 10 times higher iron dust solubility in the Southern Ocean, combined with changes in sedimentary flux, we obtain an atmospheric CO2 reduction of 13 ppm. The high uncertainty in the iron fluxes does not allow us to determine the net direction and magnitude of variations in atmospheric CO2 due to changes in the iron cycle. Our model does not account for changes to iron-binding ligand concentrations that could modify the results. We conclude that when evaluating glacial-interglacial changes in the ocean iron cycle, not only surface but also seafloor fluxes must be taken into account. |
format |
Article in Journal/Newspaper |
author |
Muglia, Juan Somes, Christopher J. Nickelsen, Levin Schmittner, Andreas |
spellingShingle |
Muglia, Juan Somes, Christopher J. Nickelsen, Levin Schmittner, Andreas Combined Effects of Atmospheric and Seafloor Iron Fluxes to the Glacial Ocean |
author_facet |
Muglia, Juan Somes, Christopher J. Nickelsen, Levin Schmittner, Andreas |
author_sort |
Muglia, Juan |
title |
Combined Effects of Atmospheric and Seafloor Iron Fluxes to the Glacial Ocean |
title_short |
Combined Effects of Atmospheric and Seafloor Iron Fluxes to the Glacial Ocean |
title_full |
Combined Effects of Atmospheric and Seafloor Iron Fluxes to the Glacial Ocean |
title_fullStr |
Combined Effects of Atmospheric and Seafloor Iron Fluxes to the Glacial Ocean |
title_full_unstemmed |
Combined Effects of Atmospheric and Seafloor Iron Fluxes to the Glacial Ocean |
title_sort |
combined effects of atmospheric and seafloor iron fluxes to the glacial ocean |
publisher |
AGU (American Geophysical Union) |
publishDate |
2017 |
url |
https://oceanrep.geomar.de/id/eprint/40276/ https://oceanrep.geomar.de/id/eprint/40276/7/Muglia_et_al-2017-Paleoceanography.pdf https://doi.org/10.1002/2016PA003077 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
https://oceanrep.geomar.de/id/eprint/40276/7/Muglia_et_al-2017-Paleoceanography.pdf Muglia, J., Somes, C. J. , Nickelsen, L. and Schmittner, A. (2017) Combined Effects of Atmospheric and Seafloor Iron Fluxes to the Glacial Ocean. Open Access Paleoceanography, 32 (11). pp. 1204-1218. DOI 10.1002/2016PA003077 <https://doi.org/10.1002/2016PA003077>. doi:10.1002/2016PA003077 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1002/2016PA003077 |
container_title |
Paleoceanography |
container_volume |
32 |
container_issue |
11 |
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1204 |
op_container_end_page |
1218 |
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1784901182301405184 |