| Registro completo |
| Provedor de dados: |
ArchiMer
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| País: |
France
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| Título: |
Modelling N2 fixation related to Trichodesmium sp.: driving processes and impacts on primary production in the tropical Pacific Ocean
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| Autores: |
Dutheil, Cyril
Aumont, Olivier
Gorgues, Thomas
Lorrain, Anne
Bonnet, Sophie
Rodier, Martine
Dupouy, Cecile
Shiozaki, Takuhei
Menkes, Christophe
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| Data: |
2018-07
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| Ano: |
2018
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| Resumo: |
Dinitrogen fixation is now recognized as one of the major sources of bio-available nitrogen in the ocean. Thus, N2 fixation sustains a significant part of the global primary production by supplying the most common limiting nutrient for phytoplankton growth. The Oligotrophy to UlTra-oligotrophy PACific Experiment (OUTPACE) improved the data coverage of the western tropical South Pacific, an area recently recognized as a hotspot of N2 fixation. This new development leads us to develop and test an explicit N2 fixation formulation based on the Trichodesmium physiology (the most studied nitrogen fixer) within a 3-D coupled dynamical–biogeochemical model (ROMS-PISCES). We performed a climatological numerical simulation that is able to reproduce the main physical (e.g. sea surface temperature) and biogeochemical patterns (nutrient and chlorophyll concentrations, as well as N2 fixation) in the tropical Pacific. This simulation displayed a Trichodesmium regional distribution that extends from 150°E to 120°W in the south tropical Pacific, and from 120°E to 140°W in the north tropical Pacific. The local simulated maximuma were found around islands (Hawaii, Fiji, Samoa, New Caledonia, Vanuatu). We assessed that 15% of the total primary production may be due to Trichodesmium in the low-nutrient low-chlorophyll regions (LNLC) of the tropical Pacific. Comparison between our explicit and the often used (in biogeochemical models) implicit parameterization of N2 fixation showed that the latter leads to an underestimation of N2 fixation rates by about 25% in LNLC regions. Finally, we established that iron fluxes from island sediments control the spatial distribution of Trichodesmium biomasses in the western tropical South Pacific. Note, this last result does not take into account the iron supply from rivers and hydrothermal sources, which may well be of importance in a region known for its strong precipitation rates and volcanic activity.
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| Tipo: |
Text
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| Idioma: |
Inglês
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| Identificador: |
https://archimer.ifremer.fr/doc/00419/53042/53979.pdf
https://archimer.ifremer.fr/doc/00419/53042/57672.pdf
https://archimer.ifremer.fr/doc/00419/53042/57673.pdf
DOI:10.5194/bg-15-4333-2018
https://archimer.ifremer.fr/doc/00419/53042/
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| Editor: |
Copernicus Gesellschaft Mbh
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| Formato: |
application/pdf
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| Fonte: |
Biogeosciences (1726-4170) (Copernicus Gesellschaft Mbh), 2018-07 , Vol. 15 , N. 14 , P. 4333-4352
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| Direitos: |
Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License.
info:eu-repo/semantics/openAccess
restricted use
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