Data/hora: 26/07/2024 22:48:12

Provedor de dados: 	Institutional Archive of Ifreme (ArchiMer)	
País: 	France	
Título: 	Nitrogen fixation in the eastern Atlantic reaches similar levels in the Southern and Northern Hemisphere	
Autores: 	Fonseca-batista, Debany; Dehairs, Frank; Riou, Virginie; Fripiat, Francois; Elskens, Marc; Deman, Florian; Brion, Natacha; Queroue, Fabien; Bode, Maya; Auel, Holger.	
Data: 	2017-01	
Ano: 	2017	
Palavras-chave: 	Nitrogen fixation; Atlantic Ocean; Primary production.	
Resumo: 	Euphotic layer dinitrogen (N-2) fixation and primary production (PP) were measured in the eastern Atlantic Ocean (38 degrees N-21 degrees S) using N-15(2) and C-13 bicarbonate tracer incubations. This region is influenced by Saharan dust deposition and waters with low nitrogen to phosphorus (N/P) ratios originating from the Subantarctic and the Benguela upwelling system. Depth-integrated rates of N-2 fixation in the north (0 degrees N-38 degrees N) ranged from 59 to 370 mu mol N m(-2) d(-1), with the maximal value at 19 degrees N under the influence of the northwest African upwelling. Diazotrophic activity in the south (0 degrees S-21 degrees S), though slightly lower, was surprisingly close to observations in the north, with values ranging from 47 to 119 mu mol N m(-2) d(-1). Our North Atlantic N-2 fixation rates correlate well with dust deposition, while those in the South Atlantic correlate strongly with excess phosphate relative to nitrate. There, the necessary iron is assumed to be supplied from the Benguela upwelling system. When converting N-2 fixation to carbon uptake using a Redfield ratio (6.6), we find that N-2 fixation may support up to 9% of PP in the subtropical North Atlantic (20 degrees N-38 degrees N), 5% in the tropical North Atlantic (0 degrees N-20 degrees N), and 1% of PP in the South Atlantic (0 degrees S-21 degrees S). Combining our data with published data sets, we estimate an annual N input of 27.610 Tg N yr(-1) over the open Atlantic Ocean, 11% of which enters the region between 20 degrees N and 50 degrees N, 71% between 20 degrees N and 10 degrees S, and 18% between 10 degrees N and 45 degrees S.	
Tipo: 	Text	
Idioma: 	Inglês	
Identificador: 	https://archimer.ifremer.fr/doc/00379/49009/49451.pdf

https://archimer.ifremer.fr/doc/00379/49009/49452.pdf

https://archimer.ifremer.fr/doc/00379/49009/49453.xlsx

https://archimer.ifremer.fr/doc/00379/49009/49454.xlsx

DOI:10.1002/2016JC012335

https://archimer.ifremer.fr/doc/00379/49009/	
Editor: 	Amer Geophysical Union	
Formato: 	application/pdf	
Fonte: 	Journal Of Geophysical Research-oceans (2169-9275) (Amer Geophysical Union), 2017-01 , Vol. 122 , N. 1 , P. 587-601	
Fonte: 	2016. American Geophysical Union. All Rights Reserved.

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