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Niche construction by non-diazotrophs for N2 fixers in the eastern tropical North Atlantic Ocean

Citation

Singh, A and Bach, LT and Fischer, T and Hauss, H and Kiko, R and Paul, AJ and Stange, P and Vandromme, P and Riebesell, U, Niche construction by non-diazotrophs for N2 fixers in the eastern tropical North Atlantic Ocean, Geophysical Research Letters, 44, (13) pp. 6904-6913. ISSN 0094-8276 (2017) [Refereed Article]


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Copyright 2019 American Geophysical Union

DOI: doi:10.1002/2017GL074218

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.

Item Details

Item Type:Refereed Article
Keywords:nitrogen fixation, phytoplankton, niche construction
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Biological Oceanography
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
UTAS Author:Bach, LT (Dr Lennart Bach)
ID Code:133666
Year Published:2017
Web of Science® Times Cited:5
Deposited By:Ecology and Biodiversity
Deposited On:2019-07-05
Last Modified:2019-08-08
Downloads:3 View Download Statistics

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