Menkes¹, Christophe, Sean Kennan², Pierre Flament³, Yves Dandonneau¹, Michael Landry³, Emile Marchal¹, Jérôme Vialard¹, Gisèle Champalbert⁴ and Marie-Hélène Radenac⁵ and Pierre Dutrieux³

¹LODYC Case 100, UPMC, 4 place Jussieu, 75252 Paris 5, France, Tel: 33 1 44 27 51 57, Fax: 33 1 44 27 71 59, E-mail: menkes@lodyc.jussieu.fr, ²Nova University, USA, ³University of Hawaii, USA, ⁴IRD, Senegal and ⁵LEGOS, France

Tropical instability vortices: a major control of the ecosystem in the tropical Pacific and Atlantic Oceans

Tropical instability waves and vortices exert major controls on the ocean dynamics and marine biology in the equatorial Atlantic and Pacific oceans. These controls range from sub-mesoscale processes with fronts ~1 km and vertical velocities ~500 m/day to mesoscale vortex processes ~500 km with horizontal velocities ~1m/s and vertical velocities ~50 m/day. The vortices shape the equatorial upwelling into a succession of striking north-south undulations of SST and chlorophyll fronts detected in remotely-sensed data but they also shape the marine ecosystem (phytoplankton, zooplankton, micronekton) up to the highest trophic levels. They may also constitute, in the equatorial Pacific Ocean, a natural analog of an iron enrichment experiment via the vortex vertical motions. In this study, we review the present stage of observational background, present the major questions about the control of the vortices onto the marine ecosystem and present observational plans to better understand the dynamical and biological coupling on these scales.