Consistent relationship between global climate and surface nitrate utilization in the western subarctic Pacific throughout the last 500 ka
[1] The open subarctic Pacific is, at present, a high nitrate low chlorophyll (HNLC) region, where nitrate is perennially abundant at the surface. Theoretically, the HNLC status of this region is subject to modification by ocean circulation and/or micronutrient supply, with implications for the effe...
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Online Access: | https://archimer.ifremer.fr/doc/00237/34840/33281.pdf https://doi.org/10.1029/2007PA001518 https://archimer.ifremer.fr/doc/00237/34840/ |
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ftarchimer:oai:archimer.ifremer.fr:34840 2023-05-15T15:43:58+02:00 Consistent relationship between global climate and surface nitrate utilization in the western subarctic Pacific throughout the last 500 ka Galbraith, Eric D. Kienast, Markus Jaccard, Samuel L. Pedersen, Thomas F. Brunelle, Brigitte G. Sigman, Daniel M. Kiefer, Thorsten 2008-05 application/pdf https://archimer.ifremer.fr/doc/00237/34840/33281.pdf https://doi.org/10.1029/2007PA001518 https://archimer.ifremer.fr/doc/00237/34840/ eng eng Amer Geophysical Union https://archimer.ifremer.fr/doc/00237/34840/33281.pdf doi:10.1029/2007PA001518 https://archimer.ifremer.fr/doc/00237/34840/ Copyright 2008 by the American Geophysical Union. info:eu-repo/semantics/openAccess restricted use Paleoceanography (0883-8305) (Amer Geophysical Union), 2008-05 , Vol. 23 , N. 2 / PA2212 , P. 1-11 text Publication info:eu-repo/semantics/article 2008 ftarchimer https://doi.org/10.1029/2007PA001518 2021-09-23T20:25:26Z [1] The open subarctic Pacific is, at present, a high nitrate low chlorophyll (HNLC) region, where nitrate is perennially abundant at the surface. Theoretically, the HNLC status of this region is subject to modification by ocean circulation and/or micronutrient supply, with implications for the effectiveness of the biological pump and hence carbon sequestration in the ocean interior. Records of biogenic detritus in sediments from throughout the subarctic Pacific indicate that export production was generally lower during glacial maxima, while nitrogen isotope measurements from the Bering Sea have shown that nitrate consumption there was more complete during the last glacial period than it is today. Here, nitrogen isotopic analyses of bulk sediments (delta N-15(bulk)) from three deep water sites in the open subarctic Pacific are evaluated in terms of regional nitrate isotopic composition and local relative nitrate utilization. The eastern subarctic Pacific delta N-15(bulk) record bears great similarity to delta N-15(bulk) records from the western margin of North America over the last glacial cycle, suggesting that variability in the isotopic composition of subeuphotic zone nitrate, the growth substrate, is reasonably coherent throughout the northeast Pacific and dominates at these sites. However, the two western subarctic Pacific records, which lie at the heart of the HNLC region, display a different pattern, implying that significant changes in local relative nitrate utilization overlie the regional background variability. After a novel correction intended to remove the background signal associated with denitrification in the eastern tropical North Pacific, these nitrate utilization records are correlated with a benthic oxygen isotope stack reflecting global deep ocean temperature and ice volume (r(2) = 0.65). The correlation implies a strong link between global climate and subarctic Pacific nitrate utilization, with nearly complete nitrate consumption during glacial periods when export production was low. Article in Journal/Newspaper Bering Sea Subarctic Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Bering Sea Pacific Paleoceanography 23 2 n/a n/a |
institution |
Open Polar |
collection |
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
description |
[1] The open subarctic Pacific is, at present, a high nitrate low chlorophyll (HNLC) region, where nitrate is perennially abundant at the surface. Theoretically, the HNLC status of this region is subject to modification by ocean circulation and/or micronutrient supply, with implications for the effectiveness of the biological pump and hence carbon sequestration in the ocean interior. Records of biogenic detritus in sediments from throughout the subarctic Pacific indicate that export production was generally lower during glacial maxima, while nitrogen isotope measurements from the Bering Sea have shown that nitrate consumption there was more complete during the last glacial period than it is today. Here, nitrogen isotopic analyses of bulk sediments (delta N-15(bulk)) from three deep water sites in the open subarctic Pacific are evaluated in terms of regional nitrate isotopic composition and local relative nitrate utilization. The eastern subarctic Pacific delta N-15(bulk) record bears great similarity to delta N-15(bulk) records from the western margin of North America over the last glacial cycle, suggesting that variability in the isotopic composition of subeuphotic zone nitrate, the growth substrate, is reasonably coherent throughout the northeast Pacific and dominates at these sites. However, the two western subarctic Pacific records, which lie at the heart of the HNLC region, display a different pattern, implying that significant changes in local relative nitrate utilization overlie the regional background variability. After a novel correction intended to remove the background signal associated with denitrification in the eastern tropical North Pacific, these nitrate utilization records are correlated with a benthic oxygen isotope stack reflecting global deep ocean temperature and ice volume (r(2) = 0.65). The correlation implies a strong link between global climate and subarctic Pacific nitrate utilization, with nearly complete nitrate consumption during glacial periods when export production was low. |
format |
Article in Journal/Newspaper |
author |
Galbraith, Eric D. Kienast, Markus Jaccard, Samuel L. Pedersen, Thomas F. Brunelle, Brigitte G. Sigman, Daniel M. Kiefer, Thorsten |
spellingShingle |
Galbraith, Eric D. Kienast, Markus Jaccard, Samuel L. Pedersen, Thomas F. Brunelle, Brigitte G. Sigman, Daniel M. Kiefer, Thorsten Consistent relationship between global climate and surface nitrate utilization in the western subarctic Pacific throughout the last 500 ka |
author_facet |
Galbraith, Eric D. Kienast, Markus Jaccard, Samuel L. Pedersen, Thomas F. Brunelle, Brigitte G. Sigman, Daniel M. Kiefer, Thorsten |
author_sort |
Galbraith, Eric D. |
title |
Consistent relationship between global climate and surface nitrate utilization in the western subarctic Pacific throughout the last 500 ka |
title_short |
Consistent relationship between global climate and surface nitrate utilization in the western subarctic Pacific throughout the last 500 ka |
title_full |
Consistent relationship between global climate and surface nitrate utilization in the western subarctic Pacific throughout the last 500 ka |
title_fullStr |
Consistent relationship between global climate and surface nitrate utilization in the western subarctic Pacific throughout the last 500 ka |
title_full_unstemmed |
Consistent relationship between global climate and surface nitrate utilization in the western subarctic Pacific throughout the last 500 ka |
title_sort |
consistent relationship between global climate and surface nitrate utilization in the western subarctic pacific throughout the last 500 ka |
publisher |
Amer Geophysical Union |
publishDate |
2008 |
url |
https://archimer.ifremer.fr/doc/00237/34840/33281.pdf https://doi.org/10.1029/2007PA001518 https://archimer.ifremer.fr/doc/00237/34840/ |
geographic |
Bering Sea Pacific |
geographic_facet |
Bering Sea Pacific |
genre |
Bering Sea Subarctic |
genre_facet |
Bering Sea Subarctic |
op_source |
Paleoceanography (0883-8305) (Amer Geophysical Union), 2008-05 , Vol. 23 , N. 2 / PA2212 , P. 1-11 |
op_relation |
https://archimer.ifremer.fr/doc/00237/34840/33281.pdf doi:10.1029/2007PA001518 https://archimer.ifremer.fr/doc/00237/34840/ |
op_rights |
Copyright 2008 by the American Geophysical Union. info:eu-repo/semantics/openAccess restricted use |
op_doi |
https://doi.org/10.1029/2007PA001518 |
container_title |
Paleoceanography |
container_volume |
23 |
container_issue |
2 |
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n/a |
op_container_end_page |
n/a |
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1766378191896707072 |