Interhemispheric leakage of isotopically heavy nitrate in the eastern tropical Pacific during the last glacial period
We present new high-resolution N isotope records from the Gulf of Tehuantepec and the Nicaragua Basin spanning the last 50-70 ka. The Tehuantepec site is situated within the core of the north subtropical denitrification zone while the Nicaragua site is at the southern boundary. The delta N-15 record...
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Amer Geophysical Union
2010
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fttriple:oai:gotriple.eu:10670/1.n0c2ha 2023-05-15T13:31:11+02:00 Interhemispheric leakage of isotopically heavy nitrate in the eastern tropical Pacific during the last glacial period Pichevin, Laetitia Ganeshram, Raja S. Francavilla, Stephen Arellano-torres, Elsa Pedersen, Tom F. Beaufort, Luc 2010-01-01 https://doi.org/10.1029/2009PA001754 https://archimer.ifremer.fr/doc/00231/34244/32645.pdf https://archimer.ifremer.fr/doc/00231/34244/32646.pdf https://archimer.ifremer.fr/doc/00231/34244/32647.pdf https://archimer.ifremer.fr/doc/00231/34244/ en eng Amer Geophysical Union doi:10.1029/2009PA001754 10670/1.n0c2ha https://archimer.ifremer.fr/doc/00231/34244/32645.pdf https://archimer.ifremer.fr/doc/00231/34244/32646.pdf https://archimer.ifremer.fr/doc/00231/34244/32647.pdf https://archimer.ifremer.fr/doc/00231/34244/ other Archimer, archive institutionnelle de l'Ifremer Paleoceanography (0883-8305) (Amer Geophysical Union), 2010-02 , Vol. 25 , N. 1 / PA120 , P. 1-15 geo envir Text https://vocabularies.coar-repositories.org/resource_types/c_18cf/ 2010 fttriple https://doi.org/10.1029/2009PA001754 2023-01-22T16:38:59Z We present new high-resolution N isotope records from the Gulf of Tehuantepec and the Nicaragua Basin spanning the last 50-70 ka. The Tehuantepec site is situated within the core of the north subtropical denitrification zone while the Nicaragua site is at the southern boundary. The delta N-15 record from Nicaragua shows an "Antarctic" timing similar to denitrification changes observed off Peru-Chile but is radically different from the northern records. We attribute this to the leakage of isotopically heavy nitrate from the South Pacific oxygen minimum zone (OMZ) into the Nicaragua Basin. The Nicaragua record leads the other eastern tropical North Pacific (ETNP) records by about 1000 years because denitrification peaks in the eastern tropical South Pacific (ETSP) before denitrification starts to increase in the Northern Hemisphere OMZ, i.e., during warming episodes in Antarctica. We find that the influence of the heavy nitrate leakage from the ETSP is still noticeable, although attenuated, in the Gulf of Tehuantepec record, particularly at the end of the Heinrich events, and tends to alter the recording of millennial timescale denitrification changes in the ETNP. This implies (1) that sedimentary delta N-15 records from the southern parts of the ETNP cannot be used straightforwardly as a proxy for local denitrification and (2) that denitrification history in the ETNP, like in the Arabian Sea, is synchronous with Greenland temperature changes. These observations reinforce the conclusion that on millennial timescales during the last ice age, denitrification in the ETNP is strongly influenced by climatic variations that originated in the highlatitude North Atlantic region, while commensurate changes in Southern Ocean hydrography more directly, and slightly earlier, affected oxygen concentrations in the ETSP. Furthermore, the delta N-15 records imply ongoing physical communication across the equator in the shallow subsurface continuously over the last 50-70 ka. Text Antarc* Antarctic Antarctica Greenland North Atlantic Southern Ocean Unknown Antarctic Greenland Pacific Southern Ocean Paleoceanography 25 1 |
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language |
English |
topic |
geo envir |
spellingShingle |
geo envir Pichevin, Laetitia Ganeshram, Raja S. Francavilla, Stephen Arellano-torres, Elsa Pedersen, Tom F. Beaufort, Luc Interhemispheric leakage of isotopically heavy nitrate in the eastern tropical Pacific during the last glacial period |
topic_facet |
geo envir |
description |
We present new high-resolution N isotope records from the Gulf of Tehuantepec and the Nicaragua Basin spanning the last 50-70 ka. The Tehuantepec site is situated within the core of the north subtropical denitrification zone while the Nicaragua site is at the southern boundary. The delta N-15 record from Nicaragua shows an "Antarctic" timing similar to denitrification changes observed off Peru-Chile but is radically different from the northern records. We attribute this to the leakage of isotopically heavy nitrate from the South Pacific oxygen minimum zone (OMZ) into the Nicaragua Basin. The Nicaragua record leads the other eastern tropical North Pacific (ETNP) records by about 1000 years because denitrification peaks in the eastern tropical South Pacific (ETSP) before denitrification starts to increase in the Northern Hemisphere OMZ, i.e., during warming episodes in Antarctica. We find that the influence of the heavy nitrate leakage from the ETSP is still noticeable, although attenuated, in the Gulf of Tehuantepec record, particularly at the end of the Heinrich events, and tends to alter the recording of millennial timescale denitrification changes in the ETNP. This implies (1) that sedimentary delta N-15 records from the southern parts of the ETNP cannot be used straightforwardly as a proxy for local denitrification and (2) that denitrification history in the ETNP, like in the Arabian Sea, is synchronous with Greenland temperature changes. These observations reinforce the conclusion that on millennial timescales during the last ice age, denitrification in the ETNP is strongly influenced by climatic variations that originated in the highlatitude North Atlantic region, while commensurate changes in Southern Ocean hydrography more directly, and slightly earlier, affected oxygen concentrations in the ETSP. Furthermore, the delta N-15 records imply ongoing physical communication across the equator in the shallow subsurface continuously over the last 50-70 ka. |
format |
Text |
author |
Pichevin, Laetitia Ganeshram, Raja S. Francavilla, Stephen Arellano-torres, Elsa Pedersen, Tom F. Beaufort, Luc |
author_facet |
Pichevin, Laetitia Ganeshram, Raja S. Francavilla, Stephen Arellano-torres, Elsa Pedersen, Tom F. Beaufort, Luc |
author_sort |
Pichevin, Laetitia |
title |
Interhemispheric leakage of isotopically heavy nitrate in the eastern tropical Pacific during the last glacial period |
title_short |
Interhemispheric leakage of isotopically heavy nitrate in the eastern tropical Pacific during the last glacial period |
title_full |
Interhemispheric leakage of isotopically heavy nitrate in the eastern tropical Pacific during the last glacial period |
title_fullStr |
Interhemispheric leakage of isotopically heavy nitrate in the eastern tropical Pacific during the last glacial period |
title_full_unstemmed |
Interhemispheric leakage of isotopically heavy nitrate in the eastern tropical Pacific during the last glacial period |
title_sort |
interhemispheric leakage of isotopically heavy nitrate in the eastern tropical pacific during the last glacial period |
publisher |
Amer Geophysical Union |
publishDate |
2010 |
url |
https://doi.org/10.1029/2009PA001754 https://archimer.ifremer.fr/doc/00231/34244/32645.pdf https://archimer.ifremer.fr/doc/00231/34244/32646.pdf https://archimer.ifremer.fr/doc/00231/34244/32647.pdf https://archimer.ifremer.fr/doc/00231/34244/ |
geographic |
Antarctic Greenland Pacific Southern Ocean |
geographic_facet |
Antarctic Greenland Pacific Southern Ocean |
genre |
Antarc* Antarctic Antarctica Greenland North Atlantic Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica Greenland North Atlantic Southern Ocean |
op_source |
Archimer, archive institutionnelle de l'Ifremer Paleoceanography (0883-8305) (Amer Geophysical Union), 2010-02 , Vol. 25 , N. 1 / PA120 , P. 1-15 |
op_relation |
doi:10.1029/2009PA001754 10670/1.n0c2ha https://archimer.ifremer.fr/doc/00231/34244/32645.pdf https://archimer.ifremer.fr/doc/00231/34244/32646.pdf https://archimer.ifremer.fr/doc/00231/34244/32647.pdf https://archimer.ifremer.fr/doc/00231/34244/ |
op_rights |
other |
op_doi |
https://doi.org/10.1029/2009PA001754 |
container_title |
Paleoceanography |
container_volume |
25 |
container_issue |
1 |
_version_ |
1766016580667310080 |