Aquatic Sciences Meeting, Albuquerque 2001

SS24 The Ecology of Pelagic Gelatinous Zooplankton

Date: Monday, February 12, 2001, Time: 11:45:00 AM

Location: Acoma/Zuni/Tesuque

Gorsky, G, , UPMC/CNRS/INSU, Observatoire Oceanologique, Villefranche sur mer, France, gorsky@obs-vlfr.fr

Blanchot, J, , IRD/Station Biologique de ROSCOFF, ROSCOFF, France, blanchot@sb-roscoff.fr

APPENDICULARIAN GRAZING ON PICOPHYTOPLANKTON

Natural picophytoplankton populations (Prochlorococcus, Synechococcus and picoeucaryots) from the western equatorial Pacific were analyzed by Flow cytometry during a cross-equatorial latitudinal transect. Prochlorococcus dominated numerically with abundance of one order of magnitude higher than cyanobacteria, constituting an important biomass particularly in oligotrophic waters. No metazoans are known to graze on this submicron size class. Appendicularians are efficient filter feeders of micron size particles, with nearly 100% retention efficiency for particles >2 µm. Onboard experiments demonstrated the potential of appendicu-larians to feed on submicron picophytoplankton and laboratory experiments confirmed these observations. Results will be presented on house gut and fecal pellet content of different appendicularian species from the equatorial Pacific, and the possibility of selective digestion will be discussed.

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Aquatic Sciences Meeting, Albuquerque 2001

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