Nitrogen Isotope Evidence for Changing Arctic Ocean Ventilation Regimes During the Cenozoic
Abstract In this work, I report on the coupling of dinitrogen (N2) 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 stratif...
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ftdoajarticles:oai:doaj.org/article:b4f3be0854c6404584cf9e00f6891028 2024-09-15T17:53:05+00:00 Nitrogen Isotope Evidence for Changing Arctic Ocean Ventilation Regimes During the Cenozoic Jochen Knies 2022-09-01T00:00:00Z https://doi.org/10.1029/2022GL099512 https://doaj.org/article/b4f3be0854c6404584cf9e00f6891028 EN eng Wiley https://doi.org/10.1029/2022GL099512 https://doaj.org/toc/0094-8276 https://doaj.org/toc/1944-8007 1944-8007 0094-8276 doi:10.1029/2022GL099512 https://doaj.org/article/b4f3be0854c6404584cf9e00f6891028 Geophysical Research Letters, Vol 49, Iss 17, Pp n/a-n/a (2022) Arctic Ocean Cenozoic nitrogen isotopes climate Geophysics. Cosmic physics QC801-809 article 2022 ftdoajarticles https://doi.org/10.1029/2022GL099512 2024-08-05T17:49:10Z Abstract In this work, I report on the coupling of dinitrogen (N2) 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 N2‐fixation by phytoplankton harboring diazotrophic bacterial symbionts. A positive shift of 5‰ in the δ15N 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 Ocean North Atlantic Phytoplankton Directory of Open Access Journals: DOAJ Articles Geophysical Research Letters 49 17 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Arctic Ocean Cenozoic nitrogen isotopes climate Geophysics. Cosmic physics QC801-809 |
spellingShingle |
Arctic Ocean Cenozoic nitrogen isotopes climate Geophysics. Cosmic physics QC801-809 Jochen Knies Nitrogen Isotope Evidence for Changing Arctic Ocean Ventilation Regimes During the Cenozoic |
topic_facet |
Arctic Ocean Cenozoic nitrogen isotopes climate Geophysics. Cosmic physics QC801-809 |
description |
Abstract In this work, I report on the coupling of dinitrogen (N2) 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 N2‐fixation by phytoplankton harboring diazotrophic bacterial symbionts. A positive shift of 5‰ in the δ15N 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 |
Jochen Knies |
author_facet |
Jochen Knies |
author_sort |
Jochen Knies |
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://doi.org/10.1029/2022GL099512 https://doaj.org/article/b4f3be0854c6404584cf9e00f6891028 |
genre |
Arctic Ocean North Atlantic Phytoplankton |
genre_facet |
Arctic Ocean North Atlantic Phytoplankton |
op_source |
Geophysical Research Letters, Vol 49, Iss 17, Pp n/a-n/a (2022) |
op_relation |
https://doi.org/10.1029/2022GL099512 https://doaj.org/toc/0094-8276 https://doaj.org/toc/1944-8007 1944-8007 0094-8276 doi:10.1029/2022GL099512 https://doaj.org/article/b4f3be0854c6404584cf9e00f6891028 |
op_doi |
https://doi.org/10.1029/2022GL099512 |
container_title |
Geophysical Research Letters |
container_volume |
49 |
container_issue |
17 |
_version_ |
1810295091174047744 |