The interaction between mesoscale eddies and seamounts modifies water circulation and affect the transport of nutrients and the abundance of organisms. The impact of these processes on zooplankton communities has not been fully explored. This study investigates how the interaction between the seamounts and the Vitoria Eddy (VE) influences zooplankton abundance and particulate organic carbon (POC) vertical flux along the Vitoria-Trindade Seamount Chain (VTC), Southwestern Atlantic Ocean. Vertical profiles using the UVP5 were performed along two transects (32 stations) near the VTC, during the summer of 2017. Rhizaria was dominant in all stations, contributing up to 65% to the zooplankton total abundance. Highest zooplankton abundances and POC fluxes occurred at stations simultaneously influenced by the shallow seamounts and the VE activity, as well as at stations only influenced by the VE. The combination of the seamount topography and the VE circulation increased local productivity and the accumulation and entrapment of particles, increasing zooplankton abundance and POC flux. Our results suggest that the energetic VE amplified the flow-topography effects of the shallow seamounts in the euphotic layer. The seamount-eddy interaction provides a substantial rise in the potential of carbon export to depth in the Southwestern Atlantic Ocean oligotrophic waters, making the VTC and other seamount chains potential carbon export hotspots.

Primary Presenter: Rubens Lopes, University of Sao Paulo (rubens@usp.br)

Authors:

Gleice Santos, University of São Paulo  (gleicesantos@usp.br)

Silvana Penninck, University of São Paulo  (sbatinck@alumni.usp.br)

Ilson Silveira, University of São Paulo  (ilson.silveira@usp.br)

Lionel Guidi, Laboratoire d'Océanographie de Villefranche  (lionel.guidi@imev-mer.fr)

Amanda Elineau, Laboratoire d'Océanographie de Villefranche  (amanda.elineau@imev-mer.fr)

Paulo Calil, Helmholtz-Zentrum Hereon  (paulo.calil@hereon.de)

Rubens Lopes, University of São Paulo  (rubens@usp.br)