Heterotrophic protists as a trophic link between picocyanobacteria and the pearl oyster Pinctada margaritifera in the Takapoto lagoon Tuamotu Archipelago, French PolynesiaReport as inadecuate




Heterotrophic protists as a trophic link between picocyanobacteria and the pearl oyster Pinctada margaritifera in the Takapoto lagoon Tuamotu Archipelago, French Polynesia - Download this document for free, or read online. Document in PDF available to download.

1 EPHE - École pratique des hautes études 2 Station de l-Houmeau 3 LIENSs - LIttoral ENvironnement et Sociétés - UMR 7266 4 SBR - Station biologique de Roscoff Roscoff 5 IFREMER LER-LR, Avenue Jean Monnet, BP 171, 34203 Sète Cedex, France 6 IFREMER - Institut Français de Recherche pour l-Exploitation de la Mer

Abstract : Pearl oysters are farmed in oligotrophic tropical atoll lagoons where planktonic communitiesare dominated by production from cyanobacteria smaller than 2 μm. Paradoxically, the pearloyster Pinctada margaritifera only retains particles larger than 2 μm. In this study, we assess the relativecontribution of hetero-mixotrophic microbiota to the available planktonic resource. In TakapotoAtoll, picocyanobacteria are the dominant biomass 20 μg C l–1. The carbon biomass of ciliates anddinoflagellates ranges from 1 to 24 and 0.5 to 5 μg C l–1 respectively, with a mean of 6 μg C l–1 for ciliatesand 2 μg C l–1 for dinoflagellates. The possible retention by P. margaritifera on a natural protistsuspension was investigated. Due to its high clearance rates ca 20 l h–1 g–1 the pearl oyster retained85 μg C h–1 g–1 from ciliates and 65 μg C h–1 g–1 from dinoflagellates. Conversely, cyanobacteria werenot efficiently retained by the bivalve and did not efficiently contribute to its diet. From our experiments,we concluded that hetero-mixotrophic protists rapidly and efficiently process the picoplanktonicresource towards filter-feeders, particularly pearl oysters.

Keywords : Protists , Atoll lagoon , Pearl oysters, Pinctada margaritifera,Picoplankton,Trophic resource





Author: P. Loret - S. Le Gall - C. Dupuy - J. Blanchot - A. Pastoureaud - B. Delesalle - X. Caisey - G. Jonquières -

Source: https://hal.archives-ouvertes.fr/



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