Assimilation and oxidation of urea‐derived nitrogen in the summer Arctic Ocean
Abstract Urea sinks are mainly associated with assimilation by phytoplankton. However, recent studies have shown that there is a process by which nitrifiers convert urea‐derived nitrogen (urea‐N) into nitrate. We examined these two processes in the shelf and off‐shelf regions of the Arctic Ocean. Ur...
Published in: | Limnology and Oceanography |
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crwiley:10.1002/lno.11950 2024-10-06T13:46:22+00:00 Assimilation and oxidation of urea‐derived nitrogen in the summer Arctic Ocean Shiozaki, Takuhei Hashihama, Fuminori Endo, Hisashi Ijichi, Minoru Takeda, Noriko Makabe, Akiko Fujiwara, Amane Nishino, Shigeto Harada, Naomi Japan Society for the Promotion of Science Ministry of Education, Culture, Sports, Science and Technology 2021 http://dx.doi.org/10.1002/lno.11950 https://onlinelibrary.wiley.com/doi/pdf/10.1002/lno.11950 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/lno.11950 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.1002/lno.11950 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Limnology and Oceanography volume 66, issue 12, page 4159-4170 ISSN 0024-3590 1939-5590 journal-article 2021 crwiley https://doi.org/10.1002/lno.11950 2024-09-11T04:17:48Z Abstract Urea sinks are mainly associated with assimilation by phytoplankton. However, recent studies have shown that there is a process by which nitrifiers convert urea‐derived nitrogen (urea‐N) into nitrate. We examined these two processes in the shelf and off‐shelf regions of the Arctic Ocean. Urea concentration was high near the bottom in the shelf region, while it was depleted throughout the water column in the off‐shelf region. Urea‐N assimilation was generally higher in the upper euphotic zone than the lower euphotic zone. By contrast, urea‐N oxidation was low in the upper euphotic zone and increased with depth. These results indicate that urea sinks consist of a two‐layer system. We further examined the organisms involved in urea‐N oxidation and found a dominance of shallow clade ammonia‐oxidizing archaea, whose abundance was low in the upper euphotic zone and increased with depth. The abundances of archaeal ureC and amoA genes of shallow clade ammonia‐oxidizing archaea were well correlated ( ρ = 0.96, Spearman's correlation), suggesting that most of shallow clade ammonia‐oxidizing archaea could use urea as a source of ammonia oxidation. However, we found that the urea‐N oxidation rate often exceeded the ammonia oxidation rate while kinetics experiments suggested that ammonia oxidizers use urea less actively than ammonia. Network analyses indicated that ammonia oxidizers were closely related to other prokaryotes with the ability to decompose urea. These results suggested that ammonia‐oxidizing archaea may not necessarily use urea‐N directly. Article in Journal/Newspaper Arctic Arctic Ocean Phytoplankton Wiley Online Library Arctic Arctic Ocean Limnology and Oceanography 66 12 4159 4170 |
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Open Polar |
collection |
Wiley Online Library |
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crwiley |
language |
English |
description |
Abstract Urea sinks are mainly associated with assimilation by phytoplankton. However, recent studies have shown that there is a process by which nitrifiers convert urea‐derived nitrogen (urea‐N) into nitrate. We examined these two processes in the shelf and off‐shelf regions of the Arctic Ocean. Urea concentration was high near the bottom in the shelf region, while it was depleted throughout the water column in the off‐shelf region. Urea‐N assimilation was generally higher in the upper euphotic zone than the lower euphotic zone. By contrast, urea‐N oxidation was low in the upper euphotic zone and increased with depth. These results indicate that urea sinks consist of a two‐layer system. We further examined the organisms involved in urea‐N oxidation and found a dominance of shallow clade ammonia‐oxidizing archaea, whose abundance was low in the upper euphotic zone and increased with depth. The abundances of archaeal ureC and amoA genes of shallow clade ammonia‐oxidizing archaea were well correlated ( ρ = 0.96, Spearman's correlation), suggesting that most of shallow clade ammonia‐oxidizing archaea could use urea as a source of ammonia oxidation. However, we found that the urea‐N oxidation rate often exceeded the ammonia oxidation rate while kinetics experiments suggested that ammonia oxidizers use urea less actively than ammonia. Network analyses indicated that ammonia oxidizers were closely related to other prokaryotes with the ability to decompose urea. These results suggested that ammonia‐oxidizing archaea may not necessarily use urea‐N directly. |
author2 |
Japan Society for the Promotion of Science Ministry of Education, Culture, Sports, Science and Technology |
format |
Article in Journal/Newspaper |
author |
Shiozaki, Takuhei Hashihama, Fuminori Endo, Hisashi Ijichi, Minoru Takeda, Noriko Makabe, Akiko Fujiwara, Amane Nishino, Shigeto Harada, Naomi |
spellingShingle |
Shiozaki, Takuhei Hashihama, Fuminori Endo, Hisashi Ijichi, Minoru Takeda, Noriko Makabe, Akiko Fujiwara, Amane Nishino, Shigeto Harada, Naomi Assimilation and oxidation of urea‐derived nitrogen in the summer Arctic Ocean |
author_facet |
Shiozaki, Takuhei Hashihama, Fuminori Endo, Hisashi Ijichi, Minoru Takeda, Noriko Makabe, Akiko Fujiwara, Amane Nishino, Shigeto Harada, Naomi |
author_sort |
Shiozaki, Takuhei |
title |
Assimilation and oxidation of urea‐derived nitrogen in the summer Arctic Ocean |
title_short |
Assimilation and oxidation of urea‐derived nitrogen in the summer Arctic Ocean |
title_full |
Assimilation and oxidation of urea‐derived nitrogen in the summer Arctic Ocean |
title_fullStr |
Assimilation and oxidation of urea‐derived nitrogen in the summer Arctic Ocean |
title_full_unstemmed |
Assimilation and oxidation of urea‐derived nitrogen in the summer Arctic Ocean |
title_sort |
assimilation and oxidation of urea‐derived nitrogen in the summer arctic ocean |
publisher |
Wiley |
publishDate |
2021 |
url |
http://dx.doi.org/10.1002/lno.11950 https://onlinelibrary.wiley.com/doi/pdf/10.1002/lno.11950 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/lno.11950 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.1002/lno.11950 |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Phytoplankton |
genre_facet |
Arctic Arctic Ocean Phytoplankton |
op_source |
Limnology and Oceanography volume 66, issue 12, page 4159-4170 ISSN 0024-3590 1939-5590 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/lno.11950 |
container_title |
Limnology and Oceanography |
container_volume |
66 |
container_issue |
12 |
container_start_page |
4159 |
op_container_end_page |
4170 |
_version_ |
1812174709835431936 |