Simulating the global distribution of nitrogen isotopes in the ocean
We present a new nitrogen isotope model incorporated into the three-dimensional ocean component of a global Earth system climate model designed for millennial timescale simulations. The model includes prognostic tracers for the two stable nitrogen isotopes, 14N and 15N, in the nitrate (NO3−), phytop...
Published in: | Global Biogeochemical Cycles |
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AGU (American Geophysical Union)
2010
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Online Access: | https://oceanrep.geomar.de/id/eprint/14335/ https://oceanrep.geomar.de/id/eprint/14335/1/2009GB003767.pdf https://doi.org/10.1029/2009gb003767 |
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ftoceanrep:oai:oceanrep.geomar.de:14335 2023-05-15T18:25:40+02:00 Simulating the global distribution of nitrogen isotopes in the ocean Somes, Christopher J. Schmittner, Andreas Galbraith, Eric D. Lehmann, Moritz F. Altabet, Mark A. Montoya, Joseph P. Letelier, Ricardo M. Mix, Alan C. Bourbonnais, Annie Eby, Michael 2010 text https://oceanrep.geomar.de/id/eprint/14335/ https://oceanrep.geomar.de/id/eprint/14335/1/2009GB003767.pdf https://doi.org/10.1029/2009gb003767 en eng AGU (American Geophysical Union) https://oceanrep.geomar.de/id/eprint/14335/1/2009GB003767.pdf Somes, C. J. , Schmittner, A., Galbraith, E. D., Lehmann, M. F., Altabet, M. A., Montoya, J. P., Letelier, R. M., Mix, A. C., Bourbonnais, A. and Eby, M. (2010) Simulating the global distribution of nitrogen isotopes in the ocean. Open Access Global Biogeochemical Cycles, 24 (4). DOI 10.1029/2009gb003767 <https://doi.org/10.1029/2009gb003767>. doi:10.1029/2009gb003767 info:eu-repo/semantics/openAccess Article PeerReviewed 2010 ftoceanrep https://doi.org/10.1029/2009gb003767 2023-04-07T15:03:55Z We present a new nitrogen isotope model incorporated into the three-dimensional ocean component of a global Earth system climate model designed for millennial timescale simulations. The model includes prognostic tracers for the two stable nitrogen isotopes, 14N and 15N, in the nitrate (NO3−), phytoplankton, zooplankton, and detritus variables of the marine ecosystem model. The isotope effects of algal NO3− uptake, nitrogen fixation, water column denitrification, and zooplankton excretion are considered as well as the removal of NO3− by sedimentary denitrification. A global database of δ15NO3− observations is compiled from previous studies and compared to the model results on a regional basis where sufficient observations exist. The model is able to qualitatively and quantitatively reproduce many of the observed patterns such as high subsurface values in water column denitrification zones and the meridional and vertical gradients in the Southern Ocean. The observed pronounced subsurface minimum in the Atlantic is underestimated by the model presumably owing to too little simulated nitrogen fixation there. Sensitivity experiments reveal that algal NO3− uptake, nitrogen fixation, and water column denitrification have the strongest effects on the simulated distribution of nitrogen isotopes, whereas the effect from zooplankton excretion is weaker. Both water column and sedimentary denitrification also have important indirect effects on the nitrogen isotope distribution by reducing the fixed nitrogen inventory, which creates an ecological niche for nitrogen fixers and, thus, stimulates additional N2 fixation in the model. Important model deficiencies are identified, and strategies for future improvement and possibilities for model application are outlined. Article in Journal/Newspaper Southern Ocean OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Southern Ocean Global Biogeochemical Cycles 24 4 n/a n/a |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
We present a new nitrogen isotope model incorporated into the three-dimensional ocean component of a global Earth system climate model designed for millennial timescale simulations. The model includes prognostic tracers for the two stable nitrogen isotopes, 14N and 15N, in the nitrate (NO3−), phytoplankton, zooplankton, and detritus variables of the marine ecosystem model. The isotope effects of algal NO3− uptake, nitrogen fixation, water column denitrification, and zooplankton excretion are considered as well as the removal of NO3− by sedimentary denitrification. A global database of δ15NO3− observations is compiled from previous studies and compared to the model results on a regional basis where sufficient observations exist. The model is able to qualitatively and quantitatively reproduce many of the observed patterns such as high subsurface values in water column denitrification zones and the meridional and vertical gradients in the Southern Ocean. The observed pronounced subsurface minimum in the Atlantic is underestimated by the model presumably owing to too little simulated nitrogen fixation there. Sensitivity experiments reveal that algal NO3− uptake, nitrogen fixation, and water column denitrification have the strongest effects on the simulated distribution of nitrogen isotopes, whereas the effect from zooplankton excretion is weaker. Both water column and sedimentary denitrification also have important indirect effects on the nitrogen isotope distribution by reducing the fixed nitrogen inventory, which creates an ecological niche for nitrogen fixers and, thus, stimulates additional N2 fixation in the model. Important model deficiencies are identified, and strategies for future improvement and possibilities for model application are outlined. |
format |
Article in Journal/Newspaper |
author |
Somes, Christopher J. Schmittner, Andreas Galbraith, Eric D. Lehmann, Moritz F. Altabet, Mark A. Montoya, Joseph P. Letelier, Ricardo M. Mix, Alan C. Bourbonnais, Annie Eby, Michael |
spellingShingle |
Somes, Christopher J. Schmittner, Andreas Galbraith, Eric D. Lehmann, Moritz F. Altabet, Mark A. Montoya, Joseph P. Letelier, Ricardo M. Mix, Alan C. Bourbonnais, Annie Eby, Michael Simulating the global distribution of nitrogen isotopes in the ocean |
author_facet |
Somes, Christopher J. Schmittner, Andreas Galbraith, Eric D. Lehmann, Moritz F. Altabet, Mark A. Montoya, Joseph P. Letelier, Ricardo M. Mix, Alan C. Bourbonnais, Annie Eby, Michael |
author_sort |
Somes, Christopher J. |
title |
Simulating the global distribution of nitrogen isotopes in the ocean |
title_short |
Simulating the global distribution of nitrogen isotopes in the ocean |
title_full |
Simulating the global distribution of nitrogen isotopes in the ocean |
title_fullStr |
Simulating the global distribution of nitrogen isotopes in the ocean |
title_full_unstemmed |
Simulating the global distribution of nitrogen isotopes in the ocean |
title_sort |
simulating the global distribution of nitrogen isotopes in the ocean |
publisher |
AGU (American Geophysical Union) |
publishDate |
2010 |
url |
https://oceanrep.geomar.de/id/eprint/14335/ https://oceanrep.geomar.de/id/eprint/14335/1/2009GB003767.pdf https://doi.org/10.1029/2009gb003767 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
https://oceanrep.geomar.de/id/eprint/14335/1/2009GB003767.pdf Somes, C. J. , Schmittner, A., Galbraith, E. D., Lehmann, M. F., Altabet, M. A., Montoya, J. P., Letelier, R. M., Mix, A. C., Bourbonnais, A. and Eby, M. (2010) Simulating the global distribution of nitrogen isotopes in the ocean. Open Access Global Biogeochemical Cycles, 24 (4). DOI 10.1029/2009gb003767 <https://doi.org/10.1029/2009gb003767>. doi:10.1029/2009gb003767 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1029/2009gb003767 |
container_title |
Global Biogeochemical Cycles |
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24 |
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4 |
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1766207274202693632 |