Niche construction by non‐diazotrophs for N2 fixers in the eastern tropical North Atlantic Ocean
Abstract Diazotrophic dinitrogen (N2) fixation contributes ~76% to “new” nitrogen inputs to the sunlit open ocean, but environmental factors determining N2 fixation rates are not well constrained. Excess phosphate (phosphate–nitrate/16 > 0) and iron availability control N2 fixation rates in the e...
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| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2017-07-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1002/2017GL074218 |
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| author | Arvind Singh Lennart T. Bach Tim Fischer Helena Hauss Rainer Kiko Allanah J. Paul Paul Stange Pieter Vandromme Ulf Riebesell |
| author_facet | Arvind Singh Lennart T. Bach Tim Fischer Helena Hauss Rainer Kiko Allanah J. Paul Paul Stange Pieter Vandromme Ulf Riebesell |
| author_sort | Arvind Singh |
| collection | DOAJ |
| description | Abstract Diazotrophic dinitrogen (N2) fixation contributes ~76% to “new” nitrogen inputs to the sunlit open ocean, but environmental factors determining N2 fixation rates are not well constrained. Excess phosphate (phosphate–nitrate/16 > 0) and iron availability control N2 fixation rates in the eastern tropical North Atlantic (ETNA), but it remains an open question how excess phosphate is generated within or supplied to the phosphate‐depleted sunlit layer. Our observations in the ETNA region (8°N–15°N, 19°W–23°W) suggest that Prochlorococcus and Synechococcus, the two ubiquitous non‐diazotrophic cyanobacteria with cellular N:P ratios higher than the Redfield ratio, create an environment of excess phosphate, which cannot be explained by diapycnal mixing, atmospheric, and riverine inputs. Thus, our results unveil a new biogeochemical niche construction mechanism by non‐diazotrophic cyanobacteria for their diazotrophic phylum group members (N2 fixers). Our observations may help to understand the prevalence of diazotrophy in low‐phosphate, oligotrophic regions. |
| format | Article |
| id | doaj-art-12e80750ebba4f2cb62a6e9c2ce2341b |
| institution | DOAJ |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2017-07-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-12e80750ebba4f2cb62a6e9c2ce2341b2025-08-20T03:10:28ZengWileyGeophysical Research Letters0094-82761944-80072017-07-0144136904691310.1002/2017GL074218Niche construction by non‐diazotrophs for N2 fixers in the eastern tropical North Atlantic OceanArvind Singh0Lennart T. Bach1Tim Fischer2Helena Hauss3Rainer Kiko4Allanah J. Paul5Paul Stange6Pieter Vandromme7Ulf Riebesell8GEOMAR Helmholtz Centre for Ocean Research Kiel Kiel GermanyGEOMAR Helmholtz Centre for Ocean Research Kiel Kiel GermanyGEOMAR Helmholtz Centre for Ocean Research Kiel Kiel GermanyGEOMAR Helmholtz Centre for Ocean Research Kiel Kiel GermanyGEOMAR Helmholtz Centre for Ocean Research Kiel Kiel GermanyGEOMAR Helmholtz Centre for Ocean Research Kiel Kiel GermanyGEOMAR Helmholtz Centre for Ocean Research Kiel Kiel GermanyGEOMAR Helmholtz Centre for Ocean Research Kiel Kiel GermanyGEOMAR Helmholtz Centre for Ocean Research Kiel Kiel GermanyAbstract Diazotrophic dinitrogen (N2) fixation contributes ~76% to “new” nitrogen inputs to the sunlit open ocean, but environmental factors determining N2 fixation rates are not well constrained. Excess phosphate (phosphate–nitrate/16 > 0) and iron availability control N2 fixation rates in the eastern tropical North Atlantic (ETNA), but it remains an open question how excess phosphate is generated within or supplied to the phosphate‐depleted sunlit layer. Our observations in the ETNA region (8°N–15°N, 19°W–23°W) suggest that Prochlorococcus and Synechococcus, the two ubiquitous non‐diazotrophic cyanobacteria with cellular N:P ratios higher than the Redfield ratio, create an environment of excess phosphate, which cannot be explained by diapycnal mixing, atmospheric, and riverine inputs. Thus, our results unveil a new biogeochemical niche construction mechanism by non‐diazotrophic cyanobacteria for their diazotrophic phylum group members (N2 fixers). Our observations may help to understand the prevalence of diazotrophy in low‐phosphate, oligotrophic regions.https://doi.org/10.1002/2017GL074218environmental controlsecosystem engineeringProchlorococcusRedfield ratioSynechococcusTrichodesmium |
| spellingShingle | Arvind Singh Lennart T. Bach Tim Fischer Helena Hauss Rainer Kiko Allanah J. Paul Paul Stange Pieter Vandromme Ulf Riebesell Niche construction by non‐diazotrophs for N2 fixers in the eastern tropical North Atlantic Ocean Geophysical Research Letters environmental controls ecosystem engineering Prochlorococcus Redfield ratio Synechococcus Trichodesmium |
| title | Niche construction by non‐diazotrophs for N2 fixers in the eastern tropical North Atlantic Ocean |
| title_full | Niche construction by non‐diazotrophs for N2 fixers in the eastern tropical North Atlantic Ocean |
| title_fullStr | Niche construction by non‐diazotrophs for N2 fixers in the eastern tropical North Atlantic Ocean |
| title_full_unstemmed | Niche construction by non‐diazotrophs for N2 fixers in the eastern tropical North Atlantic Ocean |
| title_short | Niche construction by non‐diazotrophs for N2 fixers in the eastern tropical North Atlantic Ocean |
| title_sort | niche construction by non diazotrophs for n2 fixers in the eastern tropical north atlantic ocean |
| topic | environmental controls ecosystem engineering Prochlorococcus Redfield ratio Synechococcus Trichodesmium |
| url | https://doi.org/10.1002/2017GL074218 |
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