COMPETITION AND TOP-DOWN CONTROL as potential factors controlling microbial diversity in aquatic networks
Funding: WasserCluster Lunz PostDoc Fellowship
Project leader: Katharina Besemer
The objective of this project is to disentangle the mechanisms driving microbial biodiversity in aquatic ecosystems. A number of studies suggested that species sorting according to environmental conditions constrain microbial diversity in habitats with long retention times such as lakes, while mass effects support microbial diversity in habitats with short water retention times, such as streams. Competitive interactions, dispersal dynamics and interactions with other trophic levels might contribute to microbial diversity patterns. Using an experimental approach, we test the following hypotheses: (i) Competitive interactions govern community assembly in habitats with long water retention times which is reflected in the community’s phylogenetic structure (ii) the diversity of potential bacterivores influences bacterial diversity and (iii) in the absence of dispersal, microbial communities show proliferation of typical freshwater taxa. Bacterial and eukaryotic diversity and community structure are monitored using Illumina sequencing of the 16S (bacteria) and 18S (eukaryotes) rRNA gene.