Christina Kaiser

I investigate the mechanisms behind the Rhizosphere Priming Effect (i.e. the effect of the release of labile carbon and nitrogen by plant roots on microbial decomposition of soil organic matter). I developed a model which links carbon and nitrogen input by plants to microbial community composition and function in a spatially structured soil environment, and analyzes how cooperation between microbial functional groups may lead to their coexistence and the emerging of the priming effect.

The model showed that:

1. The interaction of functional microbial groups feeding on specific substrates lead to an adaptation of the microbial community, which accelerates nitrogen recycling in litter with low nitrogen content and thus alleviates microbial nitrogen limitation [1].
2. The ubiquitous presence of seemingly “useless” microbes buffers the response of soil respiration to changing environmental conditions and is key for the long-term accumulation of carbon and nitrogen stocks in soils [2].

Large rainfall events after long dry periods result in a flux of CO₂ from soil that is larger than predicted. I examined the biological and physical dynamics leading up to a CO₂ pulse after drying-rewetting [3].

Last edited: 20 December 2016