Weinbauer, M. GBF - Nat. Res. Center for Biotechnology, mgw@gbf.de
Höfle, M. GBF - Nat. Res. Center for Biotechnology, mho@gbf.de

 
UNDERSTANDYING THE DISTRIBUTION, POPULATION DYNAMICS AND LIFE STRATEGIES OF INDIVIDUAL BACTERIAL SPECIES USING MOLECULAR PROBES
 
Molecular probes such as monoclonal antibodies and oligonucleotide probes were used to determine the distribution of indigenous bacterial populations in coastal and offshore waters of the Western Mediterranean Sea and the stratified Lake Plußsee and characterize their life strategies. Populations differed with respect to their spatial distribution as e.g. along depth profiles. Protist grazing, viral lysis, dissolved organic matter (DOM) utilization and growth rates are discussed as life strategy traits for explaining the distribution of the populations. Determination of bacterial productivity in dilution cultures with different size fractions of DOM indicates that low-molecular-weight DOM is less bioreactive than total DOM. The abundance and growth rate of populations differed between the DOM fractions demonstrating that some populations can grow well on the less bioreactive DOM fraction. We estimated that viral lysis had an important impact on several populations, whereas no significant effect of viral lysis could be detected for other populations. Strong differences between populations were also found regarding to the growth rates. In undiluted cultures the growth rates were significantly lower pointing to density effects such as resource limitation or antibiosis. Life strategy characterizations were used to affiliate populations along the r-K selection continuum and as equilibrium vs opportunistic species.
 
Day: Tuesday, Feb. 2
Time: 11:15 - 11:30am
Location: Hilton of Santa Fe
 
Code: SS40TU1115H