Expansion of pelagic denitrification during early Pleistocene cooling
Bioavailable nitrogen is removed from the oceans in oxygen-deficient benthic and pelagic environments by denitrification. Future warming is predicted to reduce ocean oxygenation and to cause hypoxic regions to expand, potentially accelerating denitrification. A compilation of high-resolution sedimen...
Published in: | Earth and Planetary Science Letters |
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ftunivrhodeislan:oai:digitalcommons.uri.edu:gsofacpubs-3178 2024-02-11T09:58:51+01:00 Expansion of pelagic denitrification during early Pleistocene cooling Robinson, Rebecca S. Etourneau, Johan Martinez, Philippe M. Schneider, Ralph 2014-03-01T08:00:00Z https://digitalcommons.uri.edu/gsofacpubs/2209 https://doi.org/10.1016/j.epsl.2013.12.022 unknown DigitalCommons@URI https://digitalcommons.uri.edu/gsofacpubs/2209 doi:10.1016/j.epsl.2013.12.022 https://doi.org/10.1016/j.epsl.2013.12.022 Graduate School of Oceanography Faculty Publications Denitrification Nitrogen isotopes Oxygen minimum zone Plio-Pleistocene text 2014 ftunivrhodeislan https://doi.org/10.1016/j.epsl.2013.12.022 2024-01-15T19:10:03Z Bioavailable nitrogen is removed from the oceans in oxygen-deficient benthic and pelagic environments by denitrification. Future warming is predicted to reduce ocean oxygenation and to cause hypoxic regions to expand, potentially accelerating denitrification. A compilation of high-resolution sedimentary nitrogen isotope (δ15N) records from the eastern tropical Pacific, North Pacific, and the Arabian Sea, and a global multi-site survey are presented as evidence for weak pelagic denitrification at the end of the Pliocene warm period. Mean δ15N values increased in the major oxygen minimum zones (OMZs) between 2.1 and 1.5 Ma. Pelagic denitrification strengthened during a period of long term global cooling, despite solubility driven increases in initial oxygen contents of Antarctic intermediate and Subantarctic mode waters ventilating the OMZs. This trend is opposite to the predicted mean trend for a cooling ocean as well as to the observed glacial-interglacial variation. Several alternatives to explain the shift are proposed, including a rise in net respiration, a progressive increase in the ventilation age of the deep ocean associated with million year scale, secular cooling, and a shoaling of the remotely ventilated thermocline to shallow depths corresponding to the zone of peak subsurface respiration. Given no evidence for a net increase in production, we assert that large-scale, climate-driven changes in ocean circulation regulate long timescale variations in the extent of pelagic denitrification. Additional data and modeling are required to fully explain the observations. © 2013 Elsevier B.V. Text Antarc* Antarctic University of Rhode Island: DigitalCommons@URI Antarctic Pacific Earth and Planetary Science Letters 389 52 61 |
institution |
Open Polar |
collection |
University of Rhode Island: DigitalCommons@URI |
op_collection_id |
ftunivrhodeislan |
language |
unknown |
topic |
Denitrification Nitrogen isotopes Oxygen minimum zone Plio-Pleistocene |
spellingShingle |
Denitrification Nitrogen isotopes Oxygen minimum zone Plio-Pleistocene Robinson, Rebecca S. Etourneau, Johan Martinez, Philippe M. Schneider, Ralph Expansion of pelagic denitrification during early Pleistocene cooling |
topic_facet |
Denitrification Nitrogen isotopes Oxygen minimum zone Plio-Pleistocene |
description |
Bioavailable nitrogen is removed from the oceans in oxygen-deficient benthic and pelagic environments by denitrification. Future warming is predicted to reduce ocean oxygenation and to cause hypoxic regions to expand, potentially accelerating denitrification. A compilation of high-resolution sedimentary nitrogen isotope (δ15N) records from the eastern tropical Pacific, North Pacific, and the Arabian Sea, and a global multi-site survey are presented as evidence for weak pelagic denitrification at the end of the Pliocene warm period. Mean δ15N values increased in the major oxygen minimum zones (OMZs) between 2.1 and 1.5 Ma. Pelagic denitrification strengthened during a period of long term global cooling, despite solubility driven increases in initial oxygen contents of Antarctic intermediate and Subantarctic mode waters ventilating the OMZs. This trend is opposite to the predicted mean trend for a cooling ocean as well as to the observed glacial-interglacial variation. Several alternatives to explain the shift are proposed, including a rise in net respiration, a progressive increase in the ventilation age of the deep ocean associated with million year scale, secular cooling, and a shoaling of the remotely ventilated thermocline to shallow depths corresponding to the zone of peak subsurface respiration. Given no evidence for a net increase in production, we assert that large-scale, climate-driven changes in ocean circulation regulate long timescale variations in the extent of pelagic denitrification. Additional data and modeling are required to fully explain the observations. © 2013 Elsevier B.V. |
format |
Text |
author |
Robinson, Rebecca S. Etourneau, Johan Martinez, Philippe M. Schneider, Ralph |
author_facet |
Robinson, Rebecca S. Etourneau, Johan Martinez, Philippe M. Schneider, Ralph |
author_sort |
Robinson, Rebecca S. |
title |
Expansion of pelagic denitrification during early Pleistocene cooling |
title_short |
Expansion of pelagic denitrification during early Pleistocene cooling |
title_full |
Expansion of pelagic denitrification during early Pleistocene cooling |
title_fullStr |
Expansion of pelagic denitrification during early Pleistocene cooling |
title_full_unstemmed |
Expansion of pelagic denitrification during early Pleistocene cooling |
title_sort |
expansion of pelagic denitrification during early pleistocene cooling |
publisher |
DigitalCommons@URI |
publishDate |
2014 |
url |
https://digitalcommons.uri.edu/gsofacpubs/2209 https://doi.org/10.1016/j.epsl.2013.12.022 |
geographic |
Antarctic Pacific |
geographic_facet |
Antarctic Pacific |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Graduate School of Oceanography Faculty Publications |
op_relation |
https://digitalcommons.uri.edu/gsofacpubs/2209 doi:10.1016/j.epsl.2013.12.022 https://doi.org/10.1016/j.epsl.2013.12.022 |
op_doi |
https://doi.org/10.1016/j.epsl.2013.12.022 |
container_title |
Earth and Planetary Science Letters |
container_volume |
389 |
container_start_page |
52 |
op_container_end_page |
61 |
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1790594656974667776 |