Reitner, B. University of Vienna, a8756797@unet.univie.ac.at
Herzig, A. Biologische Station Neusiedler See,
Herndl, G. J. Netherlands Institute for Sea Research, Herndl@Nioz.nl

 
DYNAMICS IN BACTERIOPLANKTON PRODUCTION IN A SHALLOW, TEMPERATE LAKE (LAKE NEUSIEDL, AUSTRIA): LEUCINE VERSUS THYMIDINE INCORPORATION AND THEIR RELATION TO TEMPERATURE
 
The seasonal dynamics in phyto- and bacterioplankton abundance and production were studied at 3 characteristic stations (open water, large pond within the reed belt, within the reed Phragmites australis) in the shallow Lake Neusiedl and related to dissolved organic carbon (DOC) and temperature. Bacterial abundance and production correlated with temperature. Bacterial abundance ranged from 2 x 106 cells ml-1 during winter to about 10 x 106 cells ml-1 during the summer. Bacterial production calculated by thymidine (TdR) and leucine (leu) incorporation, respectively, were in good agreement at the stations in the reed belt but bacterial production based on leu incorporation was significantly lower than bacterial production based on TdR incorporation at the open water station. This was also reflected by the significantly lower molar leu : TdR incorporation ratio at this station. While TdR incorporation correlated well with temperature, no such correlation was found for leu incorporation. With increasing temperature, the molar leu : TdR incorporation ratio declined indicating that bacterioplankton invest relatively more into reproduction (cell synthesis) at higher temperatures and more into survival (biomass synthesis) at lower temperatures. Bacterioplankton carbon demand was always at least one order of magnitude higher than the carbon production of phytoplankton indicating that bacterioplankton metabolism in Lake Neusiedl is heavily dependent on non-phytoplankton sources of DOC which are probably supplied by the reed Phragmites australis and its periphytes.
 
Day: Wednesday, Feb. 3
Time: 08:30 - 08:45am
Location: Hilton of Santa Fe
 
Code: CS60WE0830H