AME 60:15-28 (2010)  -  DOI: https://doi.org/10.3354/ame01411

Bacterial community composition and potential controlling mechanisms along a trophic gradient in a barrier reef system

Markus G. Weinbauer1,2,*, Marie-Emmanuelle Kerros1,2, Chiaki Motegi1,2, Inés C. Wilhartitz3, Fereidoun Rassoulzadegan1,2, Jean-Pascal Torréton4,5, Xavier Mari4

1Microbial Ecology & Biogeochemistry Group, Université Pierre et Marie Curie-Paris 6, Laboratoire d’Océanographie de Villefranche, 06230 Villefranche-sur-Mer, France
2CNRS, Laboratoire d’Océanographie de Villefranche, 06230 Villefranche-sur-Mer, France
3EAWAG: Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, PO Box 611, 8600 Dübendorf, Switzerland
4IRD, Noumea Center, BP A5, 98848 Noumea, New Caledonia
5Present address: ECOLAG, UMR 5119, Université Montpellier II, Case 093, 34095 Montpellier, France

ABSTRACT: Bacterial abundance and community composition were investigated along trophic gradients in the barrier reef lagoon of Noumea, New Caledonia. Bacterial abundance and the percentage of high nucleic acid (%HNA) bacteria (a potential indicator for bacterial production) increased from offshore waters towards the head of the bays. 16S rRNA gene PCR and denaturing gradient gel electrophoresis (DGGE) were used as genetic fingerprints for assessing differences in bacterial community composition. Sequences of DGGE bands were assigned to (1) the genera Rugeria and Roseobacter (Rhodobacteriaceae), (2) the SAR11 cluster, (3) other Alphaproteobacteria, and (4) the genus Alteromonas. Removal of the operationally defined attached bacteria by prefiltration did not affect community profiles in offshore waters but had a strong influence in the bays, probably due to the much higher particle load and thus, attached bacteria in the bays. For the free-living community, the number of bands decreased linearly with increasing water residence time, chlorophyll a concentration, and viral abundance. Specific bands were found for offshore waters and the 2 investigated semi-enclosed bays, whereas the lagoon showed no specific bands. A similarity analysis showed specific clusters for offshore water, the lagoon, and the bays. A principle component analysis together with cluster and correlation analysis indicated that water residence time, viruses, and a complex top-down cascading effect of ciliate grazers on flagellates influenced community composition. Also, data from fingerprints of the total and free-living communities suggest that the free-living and the attached community are controlled by different mechanisms.


KEY WORDS: Diversity · Virus · Protist · Flagellate · Ciliate · Roseobacter · SAR11


Full text in pdf format  
Cite this article as: Weinbauer MG, Kerros ME, Motegi C, Wilhartitz IC, Rassoulzadegan F, Torréton JP, Mari X (2010) Bacterial community composition and potential controlling mechanisms along a trophic gradient in a barrier reef system. Aquat Microb Ecol 60:15-28. https://doi.org/10.3354/ame01411

Export citation
Mail this link - Contents Mailing Lists - RSS
- -