Modeling the impact of iron and phosphorus limitations on nitrogen fixation in the Atlantic Ocean
International audience The overarching goal of this study is to simulate subsurface N* (sensu, Gruber and Sarmiento, 1997; GS97) anomaly patterns in the North Atlantic Ocean and determine the basin wide rates of N 2 -fixation that are required to do so. We present results from a new Atlantic impleme...
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ftinsu:oai:HAL:hal-00297627v1 2023-11-12T04:22:54+01:00 Modeling the impact of iron and phosphorus limitations on nitrogen fixation in the Atlantic Ocean Coles, V. J. Hood, R. R. Horn Point Laboratory University of Maryland Center for Environmental Science (UMCES) University of Maryland System-University of Maryland System 2007-07-06 https://hal.science/hal-00297627 https://hal.science/hal-00297627/document https://hal.science/hal-00297627/file/bg-4-455-2007.pdf en eng HAL CCSD European Geosciences Union hal-00297627 https://hal.science/hal-00297627 https://hal.science/hal-00297627/document https://hal.science/hal-00297627/file/bg-4-455-2007.pdf info:eu-repo/semantics/OpenAccess ISSN: 1726-4170 EISSN: 1726-4189 Biogeosciences https://hal.science/hal-00297627 Biogeosciences, 2007, 4 (4), pp.455-479 [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/article Journal articles 2007 ftinsu 2023-10-25T16:28:36Z International audience The overarching goal of this study is to simulate subsurface N* (sensu, Gruber and Sarmiento, 1997; GS97) anomaly patterns in the North Atlantic Ocean and determine the basin wide rates of N 2 -fixation that are required to do so. We present results from a new Atlantic implementation of a coupled physical-biogeochemical model that includes an explicit, dynamic representation of N 2 -fixation with light, nitrogen, phosphorus and iron limitations, and variable stoichiometric ratios. The model is able to reproduce nitrogen, phosphorus and iron concentration variability to first order. The latter is achieved by incorporating iron deposition directly into the model's detrital iron compartment which allows the model to reproduce sharp near surface gradients in dissolved iron concentration off the west coast of Africa and deep dissolved iron concentrations that have been observed in recent observational studies. The model can reproduce the large scale N* anomaly patterns but requires relatively high rates of surface nitrogen fixation to do so (1.8×10 12 moles N yr ?1 from 10° N?30° N, 3.4×10 12 moles N yr ?1 from 25° S?65° N). In the model the surface nitrogen fixation rate patterns are not co-located with subsurface gradients in N*. Rather, the fixed nitrogen is advected away from its source prior to generating a subsurface N* anomaly. Changes in the phosphorus remineralization rate (relative to nitrogen) linearly determine the surface nitrogen fixation rate because they change the degree of phosphorus limitation, which is the dominant limitation in the Atlantic in the model. Phosphorus remineralization rate must be increased by about a factor of 2 (relative to nitrogen) in order to generate subsurface N* anomalies that are comparable to the observations. We conclude that N 2 -fixation rate estimates for the Atlantic (and globally) may need to be revised upward, which will help resolve imbalances in the global nitrogen budget suggested by Codispoti et al. (2001) and Codispoti (2007). Article in Journal/Newspaper North Atlantic Institut national des sciences de l'Univers: HAL-INSU Sarmiento ENVELOPE(-68.000,-68.000,-72.000,-72.000) |
institution |
Open Polar |
collection |
Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Coles, V. J. Hood, R. R. Modeling the impact of iron and phosphorus limitations on nitrogen fixation in the Atlantic Ocean |
topic_facet |
[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience The overarching goal of this study is to simulate subsurface N* (sensu, Gruber and Sarmiento, 1997; GS97) anomaly patterns in the North Atlantic Ocean and determine the basin wide rates of N 2 -fixation that are required to do so. We present results from a new Atlantic implementation of a coupled physical-biogeochemical model that includes an explicit, dynamic representation of N 2 -fixation with light, nitrogen, phosphorus and iron limitations, and variable stoichiometric ratios. The model is able to reproduce nitrogen, phosphorus and iron concentration variability to first order. The latter is achieved by incorporating iron deposition directly into the model's detrital iron compartment which allows the model to reproduce sharp near surface gradients in dissolved iron concentration off the west coast of Africa and deep dissolved iron concentrations that have been observed in recent observational studies. The model can reproduce the large scale N* anomaly patterns but requires relatively high rates of surface nitrogen fixation to do so (1.8×10 12 moles N yr ?1 from 10° N?30° N, 3.4×10 12 moles N yr ?1 from 25° S?65° N). In the model the surface nitrogen fixation rate patterns are not co-located with subsurface gradients in N*. Rather, the fixed nitrogen is advected away from its source prior to generating a subsurface N* anomaly. Changes in the phosphorus remineralization rate (relative to nitrogen) linearly determine the surface nitrogen fixation rate because they change the degree of phosphorus limitation, which is the dominant limitation in the Atlantic in the model. Phosphorus remineralization rate must be increased by about a factor of 2 (relative to nitrogen) in order to generate subsurface N* anomalies that are comparable to the observations. We conclude that N 2 -fixation rate estimates for the Atlantic (and globally) may need to be revised upward, which will help resolve imbalances in the global nitrogen budget suggested by Codispoti et al. (2001) and Codispoti (2007). |
author2 |
Horn Point Laboratory University of Maryland Center for Environmental Science (UMCES) University of Maryland System-University of Maryland System |
format |
Article in Journal/Newspaper |
author |
Coles, V. J. Hood, R. R. |
author_facet |
Coles, V. J. Hood, R. R. |
author_sort |
Coles, V. J. |
title |
Modeling the impact of iron and phosphorus limitations on nitrogen fixation in the Atlantic Ocean |
title_short |
Modeling the impact of iron and phosphorus limitations on nitrogen fixation in the Atlantic Ocean |
title_full |
Modeling the impact of iron and phosphorus limitations on nitrogen fixation in the Atlantic Ocean |
title_fullStr |
Modeling the impact of iron and phosphorus limitations on nitrogen fixation in the Atlantic Ocean |
title_full_unstemmed |
Modeling the impact of iron and phosphorus limitations on nitrogen fixation in the Atlantic Ocean |
title_sort |
modeling the impact of iron and phosphorus limitations on nitrogen fixation in the atlantic ocean |
publisher |
HAL CCSD |
publishDate |
2007 |
url |
https://hal.science/hal-00297627 https://hal.science/hal-00297627/document https://hal.science/hal-00297627/file/bg-4-455-2007.pdf |
long_lat |
ENVELOPE(-68.000,-68.000,-72.000,-72.000) |
geographic |
Sarmiento |
geographic_facet |
Sarmiento |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
ISSN: 1726-4170 EISSN: 1726-4189 Biogeosciences https://hal.science/hal-00297627 Biogeosciences, 2007, 4 (4), pp.455-479 |
op_relation |
hal-00297627 https://hal.science/hal-00297627 https://hal.science/hal-00297627/document https://hal.science/hal-00297627/file/bg-4-455-2007.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782337838422949888 |