Höfle, M. GBF, mho@gbf.de
Haas, H. GBF,
Dominik, K. GBF, kdo@gbf.de

 
SEASONAL SUCCESSIONS OF BACTERIOPLANKTON COMMUNITIES IN A EUTROPHIC LAKE AS DETERMINED BY 5S rRNA ANALYSIS
 
The community structure of bacterioplankton was studied during the whole vegatation period in the epilimnion of a temperate eutrophic lake (Lake Plußsee, Northern Germany) using comparative 5S rRNA analysis. On the basis of the amounts of single 5S rRNA bands obtained directly out of the bacterioplankton, estimates were made on the relative abundance of single taxonomic groups. Comparison of full and partial 5S rRNA sequences of single bands allowed identification of specific taxonomic groups and detection of changes of single taxa over time. The overall picture for the whole bacterioplankton community showed 2 to 15 abundant taxa. In spring, a rather stable community structure with 10-15 different taxonomic units was observed during the spring phytoplankton bloom. A strong reduction of this diversity occurred at the beginning of the clear water phase (early May) when only 2-5 abundant taxa were observed with one taxon dominating. During late summer a dinoflagellate bloom occurred with Comamonas acidovorans becoming the dominant bacterial species. Comparison of the seasonal changes in the community structure of the bacterioplankton with the other biota, such phyto- and zooplankton, in the lake indicated bottom up as well as top down control of the bacterioplankton community structure.
 
Day: Tuesday, Feb. 2
Time: 11:00 - 11:15am
Location: Hilton of Santa Fe
 
Code: SS40TU1100H