PD Dr. Andreas Pommerening-Röser

One key objective of our research is to draw a comprehensive picture of the phylogenetic relationships among ammonia-oxidizing bacteria. Using comparative sequence analysis of 16S rRNA- and amoA-genes as well as DNA-DNA hybridizations, a phylogenetic framework has been developed, which serves as basis for all comparative studies and the practical handling of these bacteria.

Based on phylogenetic structures a hierarchical in situ detection system is developed. This should cover both individual species and different phylogenetic and functional groupings of ammonia-oxidizing bacteria. The focus of these studies lies on investigations of pure-culture, by means of which newly designed primers or probes can be tested under laboratory conditions, before they are used under in situ conditions.

This topic forms so to say the core of our research. It coordinates information gained from in situ analyses and results of ecophysiological laboratory experiments on pure cultures of ammoniaoxidizers. Subsequent comparisons of population structures and habitat characteristics allow conclusions on evolutionary-relevant processes.

The composition of bacterial populations adapt to environmental changes within the shortest time. Thus, a central hypothesis suggests that the ecological status of an environment could be reflected by the distribution patterns of the relevant microorganisms.  As a specific component of the microbial community ammonia-oxidizing bacteria are used as environmental indicators.