Physical drivers of the nitrate seasonal variability in the Atlantic cold tongue

Radenac, Marie-Hélène; Jouanno, Julien; Tchamabi, Christine Carine; Awo, Mesmin; Bourlès, Bernard; Arnault, Sabine; Aumont, Olivier

doi:https://doi.org/10.5194/bg-17-529-2020

Articles | Volume 17, issue 2

https://doi.org/10.5194/bg-17-529-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/bg-17-529-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 17, issue 2

Research article

|

31 Jan 2020

Research article |

| 31 Jan 2020

Physical drivers of the nitrate seasonal variability in the Atlantic cold tongue

Marie-Hélène Radenac, Julien Jouanno, Christine Carine Tchamabi, Mesmin Awo, Bernard Bourlès, Sabine Arnault, and Olivier Aumont

Data sets

French PIRATA cruises: Chemical analysis data B. Bourlès, F. Baurand, S. Hillion, P. Rousselot, J. Grelet, C. Bachelier, F. Roubaud, Y. Gouriou, and R. Chuchla https://doi.org/10.17882/58141

French PIRATA cruises: S-ADCP data B. Bourlès, G. Herbert, P. Rousselot, and J. Grelet https://doi.org/10.17882/44635

French PIRATA cruises: Mooring ADCP data B. Bourlès, J. Habasque, P. Rousselot, J. Grelet, F. Roubaud, C. Bachelier, and Y. Gouriou https://doi.org/10.17882/51557

Short summary

Satellite data and a remarkable set of in situ measurements show a main bloom of microscopic seaweed, the phytoplankton, in summer and a secondary bloom in December in the central equatorial Atlantic. They are driven by a strong vertical supply of nitrate in May–July and a shorter and moderate supply in November. In between, transport of low-nitrate water from the west explains most nitrate losses in the sunlit layer. Horizontal eddy-induced processes also contribute to seasonal nitrate removal.