SS2.05 Phylogenetic and Physiologic Successions in Aquatic Bacterial Communities
Date: Monday, June 10, 2002
Time: 2:30:00 PM
Location: Carson C
HöfleMG, GBF-German Res. Center for Biotechnology, Braunschweig, Germany,
Brettar, I, , GBF-German Res. Center for Biotechnology, Braunschweig, , 
To elucidate the structure-function relationship of bacterioplankton in the central Baltic in-situ analysis was combined with bioassays using close to in-situ conditions. Two different molecular fingerprinting techniques were used to assess community structure and function of bacterioplankton without cultivation: 16S rDNA and 5S rRNA-fingerprints. The resulting fingerprints were digitised and position and size of bands were used to calculate genetic diversity of bacterial communities. Shannon indices as well as UPGMA cluster analyses were used to compare bacterioplankton communities. 16S rDNA-fingerprints of the samples from the central Baltic, which is characterised by gradients of oxygen, salinity and temperature, showed a similar composition of the communities in habitats of similar organic nutrient conditions and electron acceptor availability. In comparison to the 16S rDNA-fingerprints, 5S rRNA-fingerprints indicated that only a fraction of the community members had a high metabolic activity. Comparison of these molecular community structure data with experimental data based on the addition of various electron acceptors indicated that carbon flux within the water column was the driving force for community structure and activity of the bacterioplankton in the Baltic sea.