SS2.05 Phylogenetic and Physiologic Successions in Aquatic Bacterial Communities
Date: Monday, June 10, 2002
Time: 2:45:00 PM
Location: Carson C
 
LEBARONP, University Paris VI, Banyuls-sur-mer, France, lebaron@obs-banyuls.fr
Servais, P, , Université Libre de Bruxelles, Bruxelles, Belgium, pservais@ulb.ac.be
 
LINKING BACTERIAL ACTIVITY AND DIVERSITY PARAMETERS IN AQUATIC ECOSYSTEMS BY CELL SORTING AND FLOW CYTOMETRY
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The study of relationships between cell size, productivity and biodiversity is of key importance in microbial ecology to understand which members of natural aquatic communities are responsible for the overall bacterial activity and productivity. Cell sorting by flow cytometry of bacteria from different natural aquatic environments was used to analyse the activity of bacterial cells as a function of their biovolume and nucleic acid content. Bacterial cells from different natural samples taken along the Mediterranean coast including fresh- and sea-waters were incubated with tritiated leucine, then stained with SYBR II and sorted by flow cytometry according to their average side-angle-scattered light and/or to their fluorescence intensity. In all samples, a bell-shaped relationship was found between cell biovolume and bacterial growth rate. The cells with a high nucleic acid content were responsible for most of the bacterial production. The spatial and temporal dynamic of HNA cells was also investigated at a fixed coastal station. These results will be discussed.