Crustaceans off Chile

Image of the Month - October 2011

Number of copepod found by m² with geostrophic currents from altimetry superimposed for two different species. One of the species is more abundant closer to the coast while the other is more abundant in open oceanic waters(Credits Universidad de Concepción, Chile)

The Humboldt current system is one of the most fertile ocean area, caracterized by a cold current, and a strong upwelling off the coasts of South America. Quite a number of marine species are flourishing there, including copepods, very small (~1-2 mm long) crustaceans which are a dominant  component of the zooplankton in all oceans.

During an oceanographic campaign, zooplankton samples were taken  (top 100 m depth) off central Chile and analyzed. These data were used  to map the abundance of copepods, as total and by species, and to  associate them with satellite-monitored environmental data, including  geostrophic currents computed from altimetry. It seems that mesocale features, such as eddies, contribute to the  dispersal of some of the copepod species away from the coast (up to 500  km). This type of information enable us to better understand plankton  distribution and with it the most basic part of marine food webs.

 

Photographs of some of the copepod species studied (left Centropagesbrachiatus, middle Nannocalanus minor, right Calanoides patagoniensis). These small crustacean are about 1 or 2 mm long. (Credits Dr. Ruben Escribano Centro COPAS, Universidad de Concepción, Chile)

See also:

References

  • Morales, C.E., M.L. Torreblanca, S. Hormazabal, M. Correa, S. Nuñez, P. Hidalgo. 2010. Mesoscale structure of copepod assemblages in the coastal transition zone and oceanic waters off central-southern Chile. Progress in Oceanography 84, 158-173