Nitrogen uptake and nitrification in the subarctic North Atlantic Ocean
Abstract Nitrification, the oxidation of ammonium to nitrite and then nitrate, is often discounted as a source of nitrate in euphotic zone waters due to photoinhibition of nitrifying microorganisms and/or competition for ammonium with phytoplankton. However, there have also been counterarguments tha...
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crwiley:10.1002/lno.10784 2024-10-13T14:09:21+00:00 Nitrogen uptake and nitrification in the subarctic North Atlantic Ocean Peng, Xuefeng Fawcett, Sarah E. van Oostende, Nicolas Wolf, Martin J. Marconi, Dario Sigman, Daniel M. Ward, Bess B. National Science Foundation 2018 http://dx.doi.org/10.1002/lno.10784 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Flno.10784 https://onlinelibrary.wiley.com/doi/pdf/10.1002/lno.10784 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/lno.10784 https://aslopubs.onlinelibrary.wiley.com/doi/am-pdf/10.1002/lno.10784 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.1002/lno.10784 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#am http://onlinelibrary.wiley.com/termsAndConditions#vor Limnology and Oceanography volume 63, issue 4, page 1462-1487 ISSN 0024-3590 1939-5590 journal-article 2018 crwiley https://doi.org/10.1002/lno.10784 2024-09-23T04:36:48Z Abstract Nitrification, the oxidation of ammonium to nitrite and then nitrate, is often discounted as a source of nitrate in euphotic zone waters due to photoinhibition of nitrifying microorganisms and/or competition for ammonium with phytoplankton. However, there have also been counterarguments that nitrification represents a significant “regenerated” nitrate source to phytoplankton, augmenting the “new” nitrate supplied via physical processes. If nitrification is an appreciable nitrate source in the euphotic zone, then the assumption of a balance between nitrate uptake and organic matter export will overestimate export production. We investigated the relative importance of nitrification and nitrate uptake in the subarctic North Atlantic in late spring and late summer. The rates and vertical distributions of primary production, nitrogen uptake, and ammonium and nitrite oxidation were determined through isotope tracer experiments and the distributions of the nitrogen and oxygen isotopes of nitrate. In surface waters, ammonium and nitrite oxidation rates were low, representing an average of 5.2% and 2.5% of total euphotic zone nitrate uptake, respectively. The nitrogen and oxygen isotopes of nitrate confirmed that nitrification was not significant within the euphotic zone. Comparison of the rates of nitrogen uptake and primary production showed that while springtime phytoplankton growth could be fully supported by new nitrate and recycled ammonium, up to 50% of summertime productivity was likely fueled by dissolved organic nitrogen (DON). Uptake of DON implies that the fraction of primary production exported from surface waters in the late summer was significantly lower than the measured nitrate and ammonium uptake rates suggest. Article in Journal/Newspaper North Atlantic Subarctic Wiley Online Library Limnology and Oceanography 63 4 1462 1487 |
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Open Polar |
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Wiley Online Library |
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crwiley |
language |
English |
description |
Abstract Nitrification, the oxidation of ammonium to nitrite and then nitrate, is often discounted as a source of nitrate in euphotic zone waters due to photoinhibition of nitrifying microorganisms and/or competition for ammonium with phytoplankton. However, there have also been counterarguments that nitrification represents a significant “regenerated” nitrate source to phytoplankton, augmenting the “new” nitrate supplied via physical processes. If nitrification is an appreciable nitrate source in the euphotic zone, then the assumption of a balance between nitrate uptake and organic matter export will overestimate export production. We investigated the relative importance of nitrification and nitrate uptake in the subarctic North Atlantic in late spring and late summer. The rates and vertical distributions of primary production, nitrogen uptake, and ammonium and nitrite oxidation were determined through isotope tracer experiments and the distributions of the nitrogen and oxygen isotopes of nitrate. In surface waters, ammonium and nitrite oxidation rates were low, representing an average of 5.2% and 2.5% of total euphotic zone nitrate uptake, respectively. The nitrogen and oxygen isotopes of nitrate confirmed that nitrification was not significant within the euphotic zone. Comparison of the rates of nitrogen uptake and primary production showed that while springtime phytoplankton growth could be fully supported by new nitrate and recycled ammonium, up to 50% of summertime productivity was likely fueled by dissolved organic nitrogen (DON). Uptake of DON implies that the fraction of primary production exported from surface waters in the late summer was significantly lower than the measured nitrate and ammonium uptake rates suggest. |
author2 |
National Science Foundation |
format |
Article in Journal/Newspaper |
author |
Peng, Xuefeng Fawcett, Sarah E. van Oostende, Nicolas Wolf, Martin J. Marconi, Dario Sigman, Daniel M. Ward, Bess B. |
spellingShingle |
Peng, Xuefeng Fawcett, Sarah E. van Oostende, Nicolas Wolf, Martin J. Marconi, Dario Sigman, Daniel M. Ward, Bess B. Nitrogen uptake and nitrification in the subarctic North Atlantic Ocean |
author_facet |
Peng, Xuefeng Fawcett, Sarah E. van Oostende, Nicolas Wolf, Martin J. Marconi, Dario Sigman, Daniel M. Ward, Bess B. |
author_sort |
Peng, Xuefeng |
title |
Nitrogen uptake and nitrification in the subarctic North Atlantic Ocean |
title_short |
Nitrogen uptake and nitrification in the subarctic North Atlantic Ocean |
title_full |
Nitrogen uptake and nitrification in the subarctic North Atlantic Ocean |
title_fullStr |
Nitrogen uptake and nitrification in the subarctic North Atlantic Ocean |
title_full_unstemmed |
Nitrogen uptake and nitrification in the subarctic North Atlantic Ocean |
title_sort |
nitrogen uptake and nitrification in the subarctic north atlantic ocean |
publisher |
Wiley |
publishDate |
2018 |
url |
http://dx.doi.org/10.1002/lno.10784 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Flno.10784 https://onlinelibrary.wiley.com/doi/pdf/10.1002/lno.10784 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/lno.10784 https://aslopubs.onlinelibrary.wiley.com/doi/am-pdf/10.1002/lno.10784 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.1002/lno.10784 |
genre |
North Atlantic Subarctic |
genre_facet |
North Atlantic Subarctic |
op_source |
Limnology and Oceanography volume 63, issue 4, page 1462-1487 ISSN 0024-3590 1939-5590 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#am http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/lno.10784 |
container_title |
Limnology and Oceanography |
container_volume |
63 |
container_issue |
4 |
container_start_page |
1462 |
op_container_end_page |
1487 |
_version_ |
1812816266892673024 |