Microbial Community Assembly

Please see the extended research webpage of the Microbial Community Assembly Group here. We only maintain a limited amount of information on this webpage.

Research Focus

Our research focuses on deriving and testing general ecological principles that address the causes and consequences of microbial diversity. We seek to answer the following two central questions in microbial ecology:

• Why do microbial communities contain so many different cell types? In other words, what prevents a few cell types from evolving that perform better and outcompete the others?
• Is diversity an important determinant of the functional performance of microbial communities? If so, what are the responsible mechanisms?

We use a combination of experimental and environmental systems to address these questions. We investigate the causes of microbial diversity using experimental systems, with particular focus on metabolic specialization. The central hypothesis is that incompatibilities between different metabolic processes cause them to segregate into different cell types, thus promoting diversity. To test this hypothesis, we experimentally measure the effects of interactions between different metabolic processes and track their fate over evolutionary time-scales. We investigate the consequences of microbial diversity using environmental systems. The central hypothesis is that microbial diversity is an important determinant of functional performance. To test this hypothesis, we measure the rates and extents of different metabolic processes and test for associations with diversity. We then experimentally manipulate diversity and evaluate the consequences on different metabolic processes. Our ultimate goal is to improve our understanding about how diversity is promoted in the environment and why diversity might be important for functional performance.

Current Research Projects

Can community transcription profiles be used to predict environmental biotransformation of organic contaminants? Fenner K, Johnson DR, Helbling DE. Swiss National Science Foundation. 2013-2016.

Investigators:

• PhD student Anna Kesberg (co-advised with Kathrin Fenner)
• MS student Johanna Otto
• Technician Teresa Colangelo Failla

Predicting the metabolic profiles of cells from the topology of the universal metabolic network. Johnson DR. SystemsX program of the Swiss National Science Foundation. 2011-2013.

Investigators:

• Postdoc Marie Marchal

Cross-feeding and the maintenance of diversity in microbial ecosystems. Johnson DR. Swiss National Science Foundation. 2011-2014.

Investigators:

• PhD student Elin Lilja
• PhD student Felix Goldschmidt
• MS student Sofia van Moorsel