Nitrogen Isotope Evidence for Changing Arctic Ocean Ventilation Regimes During the Cenozoic
In this work, I report on the coupling of dinitrogen (N 2 ) fixation and denitrification in oxygen-deficient waters of the Arctic Ocean during the Paleogene. This coupling fertilized marine phytoplankton growth and favored organic carbon burial. Reduced vertical mixing due to salinity stratification...
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Online Access: | https://hdl.handle.net/10037/26926 https://doi.org/10.1029/2022GL099512 |
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ftunivtroemsoe:oai:munin.uit.no:10037/26926 2023-05-15T14:24:08+02:00 Nitrogen Isotope Evidence for Changing Arctic Ocean Ventilation Regimes During the Cenozoic Knies, Jochen Manfred 2022-09-03 https://hdl.handle.net/10037/26926 https://doi.org/10.1029/2022GL099512 eng eng Wiley Geophysical Research Letters Knies, J. (2022). Nitrogen isotope evidence for changing Arctic Ocean ventilation regimes during the Cenozoic. Geophysical Research Letters, 49, e2022GL099512 FRIDAID 2054063 doi:10.1029/2022GL099512 0094-8276 1944-8007 https://hdl.handle.net/10037/26926 Attribution 4.0 International (CC BY 4.0) openAccess Copyright 2022 The Author(s) https://creativecommons.org/licenses/by/4.0 CC-BY Journal article Tidsskriftartikkel Peer reviewed publishedVersion 2022 ftunivtroemsoe https://doi.org/10.1029/2022GL099512 2022-09-28T23:00:52Z In this work, I report on the coupling of dinitrogen (N 2 ) fixation and denitrification in oxygen-deficient waters of the Arctic Ocean during the Paleogene. This coupling fertilized marine phytoplankton growth and favored organic carbon burial. Reduced vertical mixing due to salinity stratification in a tectonically closed oceanic basin created conditions favorable for N 2 -fixation by phytoplankton harboring diazotrophic bacterial symbionts. A positive shift of 5‰ in the δ 15 N record indicates a change in the main source of biologically available nitrogen due to rapidly changing nutrient availability. I interpret this shift as a switch to Atlantic-sourced nitrate as the main nitrogen source owing to the opening of the Arctic-Atlantic gateway to the northern North Atlantic. While the timing of the opening is still disputed among the available Arctic records, I use evidence from the northern North Atlantic to argue that the Arctic Ocean has been fully ventilated since the early Neogene. Article in Journal/Newspaper Arctic Arctic Arctic Ocean North Atlantic Phytoplankton University of Tromsø: Munin Open Research Archive Arctic Arctic Ocean Geophysical Research Letters 49 17 |
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Open Polar |
collection |
University of Tromsø: Munin Open Research Archive |
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ftunivtroemsoe |
language |
English |
description |
In this work, I report on the coupling of dinitrogen (N 2 ) fixation and denitrification in oxygen-deficient waters of the Arctic Ocean during the Paleogene. This coupling fertilized marine phytoplankton growth and favored organic carbon burial. Reduced vertical mixing due to salinity stratification in a tectonically closed oceanic basin created conditions favorable for N 2 -fixation by phytoplankton harboring diazotrophic bacterial symbionts. A positive shift of 5‰ in the δ 15 N record indicates a change in the main source of biologically available nitrogen due to rapidly changing nutrient availability. I interpret this shift as a switch to Atlantic-sourced nitrate as the main nitrogen source owing to the opening of the Arctic-Atlantic gateway to the northern North Atlantic. While the timing of the opening is still disputed among the available Arctic records, I use evidence from the northern North Atlantic to argue that the Arctic Ocean has been fully ventilated since the early Neogene. |
format |
Article in Journal/Newspaper |
author |
Knies, Jochen Manfred |
spellingShingle |
Knies, Jochen Manfred Nitrogen Isotope Evidence for Changing Arctic Ocean Ventilation Regimes During the Cenozoic |
author_facet |
Knies, Jochen Manfred |
author_sort |
Knies, Jochen Manfred |
title |
Nitrogen Isotope Evidence for Changing Arctic Ocean Ventilation Regimes During the Cenozoic |
title_short |
Nitrogen Isotope Evidence for Changing Arctic Ocean Ventilation Regimes During the Cenozoic |
title_full |
Nitrogen Isotope Evidence for Changing Arctic Ocean Ventilation Regimes During the Cenozoic |
title_fullStr |
Nitrogen Isotope Evidence for Changing Arctic Ocean Ventilation Regimes During the Cenozoic |
title_full_unstemmed |
Nitrogen Isotope Evidence for Changing Arctic Ocean Ventilation Regimes During the Cenozoic |
title_sort |
nitrogen isotope evidence for changing arctic ocean ventilation regimes during the cenozoic |
publisher |
Wiley |
publishDate |
2022 |
url |
https://hdl.handle.net/10037/26926 https://doi.org/10.1029/2022GL099512 |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Arctic Ocean North Atlantic Phytoplankton |
genre_facet |
Arctic Arctic Arctic Ocean North Atlantic Phytoplankton |
op_relation |
Geophysical Research Letters Knies, J. (2022). Nitrogen isotope evidence for changing Arctic Ocean ventilation regimes during the Cenozoic. Geophysical Research Letters, 49, e2022GL099512 FRIDAID 2054063 doi:10.1029/2022GL099512 0094-8276 1944-8007 https://hdl.handle.net/10037/26926 |
op_rights |
Attribution 4.0 International (CC BY 4.0) openAccess Copyright 2022 The Author(s) https://creativecommons.org/licenses/by/4.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1029/2022GL099512 |
container_title |
Geophysical Research Letters |
container_volume |
49 |
container_issue |
17 |
_version_ |
1766296602319781888 |