The 3 He flux gauge in the Sargasso Sea: a determination of physical nutrient fluxes to the euphotic zone at the Bermuda Atlantic Time-series Site
Significant rates of primary production occur in the oligotrophic ocean, without any measurable nutrients present in the mixed layer, fueling a scientific paradox that has lasted for decades. Here, we provide a new determination of the annual mean physical supply of nitrate to the euphotic zone in t...
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2015
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Online Access: | https://doi.org/10.5194/bg-12-5199-2015 https://doaj.org/article/78635f8ad08e4bbdb753a8c1c123657b |
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ftdoajarticles:oai:doaj.org/article:78635f8ad08e4bbdb753a8c1c123657b 2023-05-15T17:37:08+02:00 The 3 He flux gauge in the Sargasso Sea: a determination of physical nutrient fluxes to the euphotic zone at the Bermuda Atlantic Time-series Site R. H. R. Stanley W. J. Jenkins S. C. Doney D. E. Lott III 2015-09-01T00:00:00Z https://doi.org/10.5194/bg-12-5199-2015 https://doaj.org/article/78635f8ad08e4bbdb753a8c1c123657b EN eng Copernicus Publications http://www.biogeosciences.net/12/5199/2015/bg-12-5199-2015.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-12-5199-2015 https://doaj.org/article/78635f8ad08e4bbdb753a8c1c123657b Biogeosciences, Vol 12, Iss 17, Pp 5199-5210 (2015) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2015 ftdoajarticles https://doi.org/10.5194/bg-12-5199-2015 2022-12-31T12:22:34Z Significant rates of primary production occur in the oligotrophic ocean, without any measurable nutrients present in the mixed layer, fueling a scientific paradox that has lasted for decades. Here, we provide a new determination of the annual mean physical supply of nitrate to the euphotic zone in the western subtropical North Atlantic. We combine a 3-year time series of measurements of tritiugenic 3 He from 2003 to 2006 in the surface ocean at the Bermuda Atlantic Time-series Study (BATS) site with a sophisticated noble gas calibrated air–sea gas exchange model to constrain the 3 He flux across the sea–air interface, which must closely mirror the upward 3 He flux into the euphotic zone. The product of the 3 He flux and the observed subsurface nitrate– 3 He relationship provides an estimate of the minimum rate of new production in the BATS region. We also apply the gas model to an earlier time series of 3 He measurements at BATS in order to recalculate new production fluxes for the 1985 to 1988 time period. The observations, despite an almost 3-fold difference in the nitrate– 3 He relationship, yield a roughly consistent estimate of nitrate flux. In particular, the nitrate flux from 2003 to 2006 is estimated to be 0.65 ± 0.14 mol m −2 yr −1 , which is ~40 % smaller than the calculated flux for the period from 1985 to 1988. The difference in nitrate flux between the time periods may be signifying a real difference in new production resulting from changes in subtropical mode water formation. Overall, the nitrate flux is larger than most estimates of export fluxes or net community production fluxes made locally for the BATS site, which is likely a reflection of the larger spatial scale covered by the 3 He technique and potentially also by the decoupling of 3 He and nitrate during the obduction of water masses from the main thermocline into the upper ocean. The upward nitrate flux is certainly large enough to support observed rates of primary production at BATS and more generally in the oligotrophic subtropical ... Article in Journal/Newspaper North Atlantic Directory of Open Access Journals: DOAJ Articles Biogeosciences 12 17 5199 5210 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
spellingShingle |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 R. H. R. Stanley W. J. Jenkins S. C. Doney D. E. Lott III The 3 He flux gauge in the Sargasso Sea: a determination of physical nutrient fluxes to the euphotic zone at the Bermuda Atlantic Time-series Site |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
Significant rates of primary production occur in the oligotrophic ocean, without any measurable nutrients present in the mixed layer, fueling a scientific paradox that has lasted for decades. Here, we provide a new determination of the annual mean physical supply of nitrate to the euphotic zone in the western subtropical North Atlantic. We combine a 3-year time series of measurements of tritiugenic 3 He from 2003 to 2006 in the surface ocean at the Bermuda Atlantic Time-series Study (BATS) site with a sophisticated noble gas calibrated air–sea gas exchange model to constrain the 3 He flux across the sea–air interface, which must closely mirror the upward 3 He flux into the euphotic zone. The product of the 3 He flux and the observed subsurface nitrate– 3 He relationship provides an estimate of the minimum rate of new production in the BATS region. We also apply the gas model to an earlier time series of 3 He measurements at BATS in order to recalculate new production fluxes for the 1985 to 1988 time period. The observations, despite an almost 3-fold difference in the nitrate– 3 He relationship, yield a roughly consistent estimate of nitrate flux. In particular, the nitrate flux from 2003 to 2006 is estimated to be 0.65 ± 0.14 mol m −2 yr −1 , which is ~40 % smaller than the calculated flux for the period from 1985 to 1988. The difference in nitrate flux between the time periods may be signifying a real difference in new production resulting from changes in subtropical mode water formation. Overall, the nitrate flux is larger than most estimates of export fluxes or net community production fluxes made locally for the BATS site, which is likely a reflection of the larger spatial scale covered by the 3 He technique and potentially also by the decoupling of 3 He and nitrate during the obduction of water masses from the main thermocline into the upper ocean. The upward nitrate flux is certainly large enough to support observed rates of primary production at BATS and more generally in the oligotrophic subtropical ... |
format |
Article in Journal/Newspaper |
author |
R. H. R. Stanley W. J. Jenkins S. C. Doney D. E. Lott III |
author_facet |
R. H. R. Stanley W. J. Jenkins S. C. Doney D. E. Lott III |
author_sort |
R. H. R. Stanley |
title |
The 3 He flux gauge in the Sargasso Sea: a determination of physical nutrient fluxes to the euphotic zone at the Bermuda Atlantic Time-series Site |
title_short |
The 3 He flux gauge in the Sargasso Sea: a determination of physical nutrient fluxes to the euphotic zone at the Bermuda Atlantic Time-series Site |
title_full |
The 3 He flux gauge in the Sargasso Sea: a determination of physical nutrient fluxes to the euphotic zone at the Bermuda Atlantic Time-series Site |
title_fullStr |
The 3 He flux gauge in the Sargasso Sea: a determination of physical nutrient fluxes to the euphotic zone at the Bermuda Atlantic Time-series Site |
title_full_unstemmed |
The 3 He flux gauge in the Sargasso Sea: a determination of physical nutrient fluxes to the euphotic zone at the Bermuda Atlantic Time-series Site |
title_sort |
3 he flux gauge in the sargasso sea: a determination of physical nutrient fluxes to the euphotic zone at the bermuda atlantic time-series site |
publisher |
Copernicus Publications |
publishDate |
2015 |
url |
https://doi.org/10.5194/bg-12-5199-2015 https://doaj.org/article/78635f8ad08e4bbdb753a8c1c123657b |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Biogeosciences, Vol 12, Iss 17, Pp 5199-5210 (2015) |
op_relation |
http://www.biogeosciences.net/12/5199/2015/bg-12-5199-2015.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-12-5199-2015 https://doaj.org/article/78635f8ad08e4bbdb753a8c1c123657b |
op_doi |
https://doi.org/10.5194/bg-12-5199-2015 |
container_title |
Biogeosciences |
container_volume |
12 |
container_issue |
17 |
container_start_page |
5199 |
op_container_end_page |
5210 |
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1766136874628284416 |