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

Abstract

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 22:215-226 (2000) - doi:10.3354/ame022215 Heterotrophic protists as a trophic link between picocyanobacteria and the pearl oyster Pinctada margaritifera in the Takapoto lagoon (Tuamotu Archipelago, French Polynesia) Pascale Loret1,*, Solange Le Gall2, Christine Dupuy2,3, Jean Blanchot4, Annie Pastoureaud2, Bruno Delesalle1, Xavier Caisey5, Gérard Jonquières5 1EPHE, URA-CNRS 1453, Université de Perpignan, 66860 Perpignan Cédex, France 2CREMA, BP 5, 17137 L¹Houmeau, France 3LBEM, Université de La Rochelle, Pôle Science, Avenue Michel Crépeau, 17042 La Rochelle, France 4IRD, Station Biologique de Roscoff, BP 74, 29682 Roscoff, France 5IFREMER/COP, BP 7004 Taravao, Tahiti, French Polynesia *Present address: Department of Oceanography, Texas A&M University, 3146 TAMU, College Station, Texas 77843-3146, USA. E-mail: ploret@ocean.tamu.edu ABSTRACT: Pearl oysters are farmed in oligotrophic tropical atoll lagoons where planktonic communities are dominated by production from cyanobacteria smaller than 2 μm. Paradoxically, the pearl oyster Pinctada margaritifera only retains particles larger than 2 μm. In this study, we assess the relative contribution of hetero/mixotrophic microbiota to the available planktonic resource. In Takapoto Atoll, picocyanobacteria are the dominant biomass (20 μg C l-1). The carbon biomass of ciliates and dinoflagellates 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 ciliates and 2 μg C l-1 for dinoflagellates. The possible retention by P. margaritifera on a natural protist suspension was investigated. Due to its high clearance rates (ca 20 l h-1 g-1) the pearl oyster retained 85 μg C h-1 g-1 from ciliates and 65 μg C h-1 g-1 from dinoflagellates. Conversely, cyanobacteria were not 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 picoplanktonic resource towards filter-feeders, particularly pearl oysters. KEY WORDS: Protists · Atoll lagoon · Pearl oysters · Pinctada margaritifera · Picoplankton · Trophic resource Full text in pdf format NextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 22, No. 3. Online publication date: October 26, 2000 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2000 Inter-Research.