Environmental characteristics of Agulhas rings affect interocean plankton transport

• DOI: 10.1126/science.1261447
• Publication Date: 2015-05-22T21:00:59Z
• Authors: Emilie Villar; Gregory K. Farrant; Michael Follows; Laurence Garczarek; Sabrina Speich; Stéphane Audic; Lucie Bittner; Bruno Blanke; Jennifer R. Brum; Christophe Brunet; Raffaella Casotti; Alison Chase; John R. Dolan; Fabrizio d’Ortenzio; Jean-Pierre Gattuso; Nicolas Grima; Lionel Guidi; Christopher N. Hill; Oliver Jahn; Jean-Louis Jamet; Hervé Le Goff; Cyrille Lepoivre; Shruti Malviya; Eric Pelletier; Jean-Baptiste Rom...; Simon Roux; Sébastien Santini; Eleonora Scalco; Sarah M. Schwenck; Atsuko Tanaka; Pierre Testor; Thomas Vannier; Flora Vincent; Adriana Zingone; Céline Dimier; Marc Picheral; Sarah Searson; Stefanie Kandels-...; ; Silvia G. Acinas; Peer Bork; Emmanuel Boss; Colomban de Vargas; Gabriel Gorsky; Hiroyuki Ogata; Stéphane Pesant; Matthew B. Sullivan; Shinichi Sunagawa; Patrick Wincker; Eric Karsenti; Chris Bowler; Fabrice Not; Pascal Hingamp; Daniele Iudicone
• Keywords: [SDE.BE] Environmental Sciences/Biodiversity and Ecology; 0301 basic medicine; 0303 health sciences; 03 medical and health sciences; 550; 13. Climate action; 14. Life underwater; [SDE.BE]Environmental Sciences/Biodiversity and Ecology

Agulhas rings provide the principal route for ocean waters to circulate from the Indo-Pacific to the Atlantic basin. Their influence on global ocean circulation is well known, but their role in plankton transport is largely unexplored. We show that, although the coarse taxonomic structure of plankton communities is continuous across the Agulhas choke point, South Atlantic plankton diversity is altered compared with Indian Ocean source populations. Modeling and in situ sampling of a young Agulhas ring indicate that strong vertical mixing drives complex nitrogen cycling, shaping community metabolism and biogeochemical signatures as the ring and associated plankton transit westward. The peculiar local environment inside Agulhas rings may provide a selective mechanism contributing to the limited dispersal of Indian Ocean plankton populations into the Atlantic.