FN Archimer Export Format
PT J
TI Feeding rate of the oyster Crassostrea gigas in a natural planktonic community of the Mediterranean Thau Lagoon
BT 
AF DUPUY, Christine
   VAQUER, André
   LAM HOAI, Thong
   ROUGIER, Claude
   MAZOUNI, Nabila
   LAUTIER, Jacques
   COLLOS, Yves
   LE GALL, Solange
AS 1:;2:;3:;4:;5:;6:;7:;8:;
FF 1:;2:;3:;4:;5:;6:;7:;8:;
C1 CREMA, UMR 10, IFREMER, CNRS, F-17137 Lhoumeau, France.
   Univ La Rochelle, LBEM, EA 3168, F-17042 La Rochelle, France.
   Univ Montpellier 2, UMR 5556, Lab Hydrobiol, F-34095 Montpellier, France.
   Univ Montpellier 2, URM 5, F-34095 Montpellier 05, France.
   IFREMER, F-34203 Sete, France.
C2 IFREMER, FRANCE
   UNIV LA ROCHELLE, FRANCE
   UNIV MONTPELLIER 2, FRANCE
   UNIV MONTPELLIER 2, FRANCE
   IFREMER, FRANCE
SI LA ROCHELLE
   SETE
SE PDG-DRV-RA-CREMA
   PDG-DRV-RH-LSETE
IN WOS Ifremer jusqu'en 2018
   copubli-univ-france
IF 1.928
TC 124
UR https://archimer.ifremer.fr/doc/2000/publication-812.pdf
LA English
DT Article
DE ;Trophic link;Picophytoplankton;Heterotrophic protist;Microbial food web;Thau Lagoon;Food source;Oyster;Bivalve
AB The Mediterranean Thau Lagoon is an important oyster farming area in Europe. Oyster growth rates are among the highest in France, although chlorophyll a concentration is low. Previous studies have demonstrated that picophytoplankton, nano-microphytoplankton, dinoflagellates and loricate ciliates such as tintinnids are abundant. However, heterotrophic flagellates and aloricate ciliates have not been investigated. The aim of this study was to assess picophytoplankton, protist and zooplankton abundances in the Lagoon and to investigate the particular structure of the microbial food web, which may explain such paradoxical oyster growth. In oligotrophic waters in the Thau Lagoon, the picoeukaryote Ostreococcus tauri is the dominant autotrophic picoplankter, with an abundance maximum in summer. On 17 August 1998, following a rainfall event, pico- and nanophytoplankton abundances were not as high as expected and we observed a high abundance of large diatoms. At this time, the available carbon resources were produced by microphytoplankton (84.5%), and picoplank-tonic cells represented only 1.27 % in terms of carbon. Heterotrophic cells were low in abundance and constituted <14% of carbon resources. In order to evaluate the importance of the 'protozoan trophic link' for energy transfer from the microbial food web to large benthic suspension feeders, the oyster Crassostrea gigas was offered a planktonic community as potential prey. In the grazing experiment, all >5 mum flagellates, microphytoplankton, dinoflagellates, ciliates and large zooplankton were retained by the oyster gills. Only flagellates <5 pm and O. tauri were not very well retained (45 and 2% respectively). The high clearance rates of C. gigas found in this experiment can be explained by a low concentration of suspended particulate matter (0.65 mg l(-1)). The oysters adapted their retention mechanism when they Lived in oligotrophic waters. These results indicate that, under the given experimental conditions, picophytoplankton did not represent a valuable trophic resource for farmed oysters because (1) C. gigas cannot retain picoparticles and (2) the picoplankton represented a poor carbon resource capable of being transferred via a weak heterotrophic protist community. In the oyster pens of the Thau Lagoon during this study, microphytoplanktonic primary producers, in particular diatoms, were the main food sources for bivalve suspension feeders.
PY 2000
PD OCT
SO Marine Ecology Progress Series
SN 0171-8630
PU Inter-Research
VL 205
UT 000165292500013
BP 171
EP 184
ID 812
ER

EF