Enhanced ocean oxygenation during Cenozoic warm periods.
Dissolved oxygen (O2) is essential for most ocean ecosystems, fuelling organisms' respiration and facilitating the cycling of carbon and nutrients. Oxygen measurements have been interpreted to indicate that the ocean's oxygen-deficient zones (ODZs) are expanding under global warming1,2. Ho...
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ftunivcam:oai:www.repository.cam.ac.uk:1810/340682 2023-07-30T04:07:03+02:00 Enhanced ocean oxygenation during Cenozoic warm periods. Auderset, Alexandra Moretti, Simone Taphorn, Björn Ebner, Pia-Rebecca Kast, Emma Wang, Xingchen T Schiebel, Ralf Sigman, Daniel M Haug, Gerald H Martínez-García, Alfredo 2022-09-02T14:05:51Z text/xml application/zip application/pdf https://doi.org/10.17863/CAM.88120 https://www.repository.cam.ac.uk/handle/1810/340682 en eng Springer Science and Business Media LLC Nature doi:10.17863/CAM.88120 https://www.repository.cam.ac.uk/handle/1810/340682 Article /704/106/47 /704/106/2738 /704/106/413 Article 2022 ftunivcam https://doi.org/10.17863/CAM.88120 2023-07-10T21:53:51Z Dissolved oxygen (O2) is essential for most ocean ecosystems, fuelling organisms' respiration and facilitating the cycling of carbon and nutrients. Oxygen measurements have been interpreted to indicate that the ocean's oxygen-deficient zones (ODZs) are expanding under global warming1,2. However, models provide an unclear picture of future ODZ change in both the near term and the long term3-6. The paleoclimate record can help explore the possible range of ODZ changes in warmer-than-modern periods. Here we use foraminifera-bound nitrogen (N) isotopes to show that water-column denitrification in the eastern tropical North Pacific was greatly reduced during the Middle Miocene Climatic Optimum (MMCO) and the Early Eocene Climatic Optimum (EECO). Because denitrification is restricted to oxygen-poor waters, our results indicate that, in these two Cenozoic periods of sustained warmth, ODZs were contracted, not expanded. ODZ contraction may have arisen from a decrease in upwelling-fuelled biological productivity in the tropical Pacific, which would have reduced oxygen demand in the subsurface. Alternatively, invigoration of deep-water ventilation by the Southern Ocean may have weakened the ocean's 'biological carbon pump', which would have increased deep-ocean oxygen. The mechanism at play would have determined whether the ODZ contractions occurred in step with the warming or took centuries or millennia to develop. Thus, although our results from the Cenozoic do not necessarily apply to the near-term future, they might imply that global warming may eventually cause ODZ contraction. Article in Journal/Newspaper Southern Ocean Apollo - University of Cambridge Repository Pacific Southern Ocean |
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Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
topic |
Article /704/106/47 /704/106/2738 /704/106/413 |
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Article /704/106/47 /704/106/2738 /704/106/413 Auderset, Alexandra Moretti, Simone Taphorn, Björn Ebner, Pia-Rebecca Kast, Emma Wang, Xingchen T Schiebel, Ralf Sigman, Daniel M Haug, Gerald H Martínez-García, Alfredo Enhanced ocean oxygenation during Cenozoic warm periods. |
topic_facet |
Article /704/106/47 /704/106/2738 /704/106/413 |
description |
Dissolved oxygen (O2) is essential for most ocean ecosystems, fuelling organisms' respiration and facilitating the cycling of carbon and nutrients. Oxygen measurements have been interpreted to indicate that the ocean's oxygen-deficient zones (ODZs) are expanding under global warming1,2. However, models provide an unclear picture of future ODZ change in both the near term and the long term3-6. The paleoclimate record can help explore the possible range of ODZ changes in warmer-than-modern periods. Here we use foraminifera-bound nitrogen (N) isotopes to show that water-column denitrification in the eastern tropical North Pacific was greatly reduced during the Middle Miocene Climatic Optimum (MMCO) and the Early Eocene Climatic Optimum (EECO). Because denitrification is restricted to oxygen-poor waters, our results indicate that, in these two Cenozoic periods of sustained warmth, ODZs were contracted, not expanded. ODZ contraction may have arisen from a decrease in upwelling-fuelled biological productivity in the tropical Pacific, which would have reduced oxygen demand in the subsurface. Alternatively, invigoration of deep-water ventilation by the Southern Ocean may have weakened the ocean's 'biological carbon pump', which would have increased deep-ocean oxygen. The mechanism at play would have determined whether the ODZ contractions occurred in step with the warming or took centuries or millennia to develop. Thus, although our results from the Cenozoic do not necessarily apply to the near-term future, they might imply that global warming may eventually cause ODZ contraction. |
format |
Article in Journal/Newspaper |
author |
Auderset, Alexandra Moretti, Simone Taphorn, Björn Ebner, Pia-Rebecca Kast, Emma Wang, Xingchen T Schiebel, Ralf Sigman, Daniel M Haug, Gerald H Martínez-García, Alfredo |
author_facet |
Auderset, Alexandra Moretti, Simone Taphorn, Björn Ebner, Pia-Rebecca Kast, Emma Wang, Xingchen T Schiebel, Ralf Sigman, Daniel M Haug, Gerald H Martínez-García, Alfredo |
author_sort |
Auderset, Alexandra |
title |
Enhanced ocean oxygenation during Cenozoic warm periods. |
title_short |
Enhanced ocean oxygenation during Cenozoic warm periods. |
title_full |
Enhanced ocean oxygenation during Cenozoic warm periods. |
title_fullStr |
Enhanced ocean oxygenation during Cenozoic warm periods. |
title_full_unstemmed |
Enhanced ocean oxygenation during Cenozoic warm periods. |
title_sort |
enhanced ocean oxygenation during cenozoic warm periods. |
publisher |
Springer Science and Business Media LLC |
publishDate |
2022 |
url |
https://doi.org/10.17863/CAM.88120 https://www.repository.cam.ac.uk/handle/1810/340682 |
geographic |
Pacific Southern Ocean |
geographic_facet |
Pacific Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
doi:10.17863/CAM.88120 https://www.repository.cam.ac.uk/handle/1810/340682 |
op_doi |
https://doi.org/10.17863/CAM.88120 |
_version_ |
1772820135242891264 |