Seasonal variations in the nitrogen isotopic composition of settling particles at station K2 in the western subarctic North Pacific
Intensive observations using hydrographical cruises and moored sediment trap deployments during 2010 and 2012 at station K2 in the North Pacific Western Subarctic Gyre (WSG) revealed seasonal changes in δ 15N of both suspended and settling particles. Suspended particles (SUS) were collected from dep...
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ftnagoyauniv:oai:nagoya.repo.nii.ac.jp:02007480 2023-10-25T01:44:12+02:00 Seasonal variations in the nitrogen isotopic composition of settling particles at station K2 in the western subarctic North Pacific Mino, Yoshihisa Sukigara, Chiho Honda, Makio C. Kawakami, Hajime Matsumoto, Kazuhiko Wakita, Masahide Kitamura, Minoru Fujiki, Tetsuichi Sasaoka, Kosei Abe, Osamu Kaiser, Jan Saino, Toshiro 2016-12 application/pdf https://nagoya.repo.nii.ac.jp/record/2007480/files/Mino et al_JO_2016_20230925.pdf eng eng Springer https://doi.org/10.1007/s10872-016-0381-1 Journal of Oceanography 6 72 819 836 0916-8370 https://nagoya.repo.nii.ac.jp/record/2007480/files/Mino et al_JO_2016_20230925.pdf This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1007/s10872-016-0381-1 Nitrogen isotopes Suspended and settling particles Nitrogen recycling Nitrification Primary productivity Western subarctic North Pacific 2016 ftnagoyauniv https://doi.org/10.1007/s10872-016-0381-1 2023-09-27T17:16:59Z Intensive observations using hydrographical cruises and moored sediment trap deployments during 2010 and 2012 at station K2 in the North Pacific Western Subarctic Gyre (WSG) revealed seasonal changes in δ 15N of both suspended and settling particles. Suspended particles (SUS) were collected from depths between the surface and 200 m; settling particles by drifting sediment traps (DST; 100–200 m) and moored sediment traps (MST; 200 and 500 m). All particles showed higher δ 15N values in winter and lower in summer, contrary to the expected by isotopic fractionation during phytoplankton nitrate consumption. We suggest that these observed isotopic patterns are due to ammonium consumption via light-controlled nitrification, which could induce variations in δ 15N(SUS) of 0.4–3.1 ‰ in the euphotic zone (EZ). The δ 15N(SUS) signature was reflected by δ 15N(DST) despite modifications during biogenic transformation from suspended particles in the EZ. δ 15N enrichment (average: 3.6 ‰) and the increase in C:N ratio (by 1.6) in settling particles suggests year-round contributions of metabolites from herbivorous zooplankton as well as TEPs produced by diatoms. Accordingly, seasonal δ 15N(DST) variations of 2.4–7.0 ‰ showed a significant correlation with primary productivity (PP) at K2. By applying the observed δ 15N(DST) vs. PP regression to δ 15N(MST) of 1.9–8.0 ‰, we constructed the first annual time-series of PP changes in the WSG. This new approach to estimate productivity can be a powerful tool for further understanding of the biological pump in the WSG, even though its validity needs to be examined carefully. journal article Other/Unknown Material Subarctic Nagoya University: NAGOYA Repository Pacific Journal of Oceanography 72 6 819 836 |
institution |
Open Polar |
collection |
Nagoya University: NAGOYA Repository |
op_collection_id |
ftnagoyauniv |
language |
English |
topic |
Nitrogen isotopes Suspended and settling particles Nitrogen recycling Nitrification Primary productivity Western subarctic North Pacific |
spellingShingle |
Nitrogen isotopes Suspended and settling particles Nitrogen recycling Nitrification Primary productivity Western subarctic North Pacific Mino, Yoshihisa Sukigara, Chiho Honda, Makio C. Kawakami, Hajime Matsumoto, Kazuhiko Wakita, Masahide Kitamura, Minoru Fujiki, Tetsuichi Sasaoka, Kosei Abe, Osamu Kaiser, Jan Saino, Toshiro Seasonal variations in the nitrogen isotopic composition of settling particles at station K2 in the western subarctic North Pacific |
topic_facet |
Nitrogen isotopes Suspended and settling particles Nitrogen recycling Nitrification Primary productivity Western subarctic North Pacific |
description |
Intensive observations using hydrographical cruises and moored sediment trap deployments during 2010 and 2012 at station K2 in the North Pacific Western Subarctic Gyre (WSG) revealed seasonal changes in δ 15N of both suspended and settling particles. Suspended particles (SUS) were collected from depths between the surface and 200 m; settling particles by drifting sediment traps (DST; 100–200 m) and moored sediment traps (MST; 200 and 500 m). All particles showed higher δ 15N values in winter and lower in summer, contrary to the expected by isotopic fractionation during phytoplankton nitrate consumption. We suggest that these observed isotopic patterns are due to ammonium consumption via light-controlled nitrification, which could induce variations in δ 15N(SUS) of 0.4–3.1 ‰ in the euphotic zone (EZ). The δ 15N(SUS) signature was reflected by δ 15N(DST) despite modifications during biogenic transformation from suspended particles in the EZ. δ 15N enrichment (average: 3.6 ‰) and the increase in C:N ratio (by 1.6) in settling particles suggests year-round contributions of metabolites from herbivorous zooplankton as well as TEPs produced by diatoms. Accordingly, seasonal δ 15N(DST) variations of 2.4–7.0 ‰ showed a significant correlation with primary productivity (PP) at K2. By applying the observed δ 15N(DST) vs. PP regression to δ 15N(MST) of 1.9–8.0 ‰, we constructed the first annual time-series of PP changes in the WSG. This new approach to estimate productivity can be a powerful tool for further understanding of the biological pump in the WSG, even though its validity needs to be examined carefully. journal article |
author |
Mino, Yoshihisa Sukigara, Chiho Honda, Makio C. Kawakami, Hajime Matsumoto, Kazuhiko Wakita, Masahide Kitamura, Minoru Fujiki, Tetsuichi Sasaoka, Kosei Abe, Osamu Kaiser, Jan Saino, Toshiro |
author_facet |
Mino, Yoshihisa Sukigara, Chiho Honda, Makio C. Kawakami, Hajime Matsumoto, Kazuhiko Wakita, Masahide Kitamura, Minoru Fujiki, Tetsuichi Sasaoka, Kosei Abe, Osamu Kaiser, Jan Saino, Toshiro |
author_sort |
Mino, Yoshihisa |
title |
Seasonal variations in the nitrogen isotopic composition of settling particles at station K2 in the western subarctic North Pacific |
title_short |
Seasonal variations in the nitrogen isotopic composition of settling particles at station K2 in the western subarctic North Pacific |
title_full |
Seasonal variations in the nitrogen isotopic composition of settling particles at station K2 in the western subarctic North Pacific |
title_fullStr |
Seasonal variations in the nitrogen isotopic composition of settling particles at station K2 in the western subarctic North Pacific |
title_full_unstemmed |
Seasonal variations in the nitrogen isotopic composition of settling particles at station K2 in the western subarctic North Pacific |
title_sort |
seasonal variations in the nitrogen isotopic composition of settling particles at station k2 in the western subarctic north pacific |
publisher |
Springer |
publishDate |
2016 |
url |
https://nagoya.repo.nii.ac.jp/record/2007480/files/Mino et al_JO_2016_20230925.pdf |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Subarctic |
genre_facet |
Subarctic |
op_relation |
https://doi.org/10.1007/s10872-016-0381-1 Journal of Oceanography 6 72 819 836 0916-8370 https://nagoya.repo.nii.ac.jp/record/2007480/files/Mino et al_JO_2016_20230925.pdf |
op_rights |
This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1007/s10872-016-0381-1 |
op_doi |
https://doi.org/10.1007/s10872-016-0381-1 |
container_title |
Journal of Oceanography |
container_volume |
72 |
container_issue |
6 |
container_start_page |
819 |
op_container_end_page |
836 |
_version_ |
1780741631497994240 |