Community response of zooplankton to oceanographic changes (2002–2012) in the central/southern upwelling system of Chile

Publicado en Progress in Oceanography, v. 142:17-29 

Medellín-Mora, J., Escribano, R. and Schneider, W.

Año de publicación 2016
  • Doctoral Program in Oceanography, Universidad de Concepción, Chile
  • Millennium Institute of Oceanography (IMO) and Department of Oceanography, Faculty of Natural and Oceanographic Sciences, Universidad de Concepción, P.O. Box 160, Concepción, Chile




Proyecto CRN3094


•Zooplankton dynamics is strongly linked to variability of the upwelling process.

•Climate-induced forcing on upwelling can alter size structure-composition of zooplankton.

•Biological communities of upwelling systems are reorganizing upon ongoing climate change.


A 10-year time series (2002-2012) at Station 18 off central/southern Chile allowed us to study variations in zooplankton along with interannual variability and trends in oceanographic conditions. We used an automated analysis program (ZooImage) to assess changes in the mesozooplankton size structure and the composition of the taxa throughout the entire community. Oceanographic conditions changed over the decade: the water column became less stratified, more saline, and colder the mixed layer deepened and the oxygen minimum zone became shallower during the second half of the time series (2008-2012) in comparison with the first period (2002-2007). Both the size structure and composition of the zooplankton were significantly associated with oceanographic changes. Taxonomic and size diversity of the zooplankton community increased to the more recent period. For the second period, small sized copepods (<1 mm) decreased in abundance, being replaced by larger sized (>1.5 mm) and medium size copepods (1-1.5 mm), whereas euphausiids, decapod larvae, appendicularian and ostracods increased their abundance during the second period. These findings indicated that the zooplankton community structure in this eastern boundary ecosystem was strongly influenced by variability of the upwelling process. Thus, climate-induced forcing of upwelling trends can alter the zooplankton community in this highly productive region with potential consequences for the ecosystem food web.