SS2.05 Phylogenetic and Physiologic Successions in Aquatic Bacterial Communities
Date: Thursday, June 13, 2002
Location: Poster Session - VCC
 
DebroasD, Lab. Biol. Protistes, Univ. Blaise Pascal, 63177 Aubiere, France, didier.debroas@free.fr
Basset, M, , Univ. Blaise Pascal, Aubiere, France, 
Domaizon, I, , Univ. Blaise Pascal, Aubiere, France, 
Richardot, M, , Univ. Blaise Pascal, Aubiere, France, 
 
TEMPORAL SUCCESSION OF BACTERIAL POPULATIONS IN TWO LAKES DIFFERING IN TROPHIC STATUS
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The temporal succession of bacterial community composition was studied in the euphotic zone of an oligo-mesotrophic and a eutrophic lake, by using in situ hybridization (FISH) and terminal restriction fragment length polymorphism (T-RFLP). The number of operational taxonomic units (OTUs) were slightly higher in the oligo-mesotrophic ecosystem but the specific diversity of the bacterial community did not differ between both lakes. 50% of OTUs were detected in both ecosystems and, at any given date, the bacterial community was dominated by 6 to 7 OTUs that accounted for 57% to 98% of the total community. The bacterial community composition was analysed in relation to environmental variables and the effects of level of predation and nutrients were tested in mesocosms. Results indicate that lake water chemistry, phytoplanktonic community and presence of grazers can have an impact on the composition of these communities.