Responses of soil microbes to drought and rewetting
Ecosystems are exposed to more frequent and extreme drought and rainfall events due to current and predicted climatic warming. As soil moisture regulates soil microbes and microbes are important for many ecosystem functions, it is important to understand how soil microbes and microbial driven processes respond to drought and rainfall events. This project studies:
The microbial mechanisms underlying drought and rewetting
Rewetting of dry soil produces an immediate pulse of CO2 from soil. This phenomenon has been well-known for nearly a century and has been named the “Birch effect” after one of its first documenters. The CO2pulse is hypothesized to be caused by the mineralization of resources made available by the rewetting or by increased respiration of osmolytes produced during the soil drying. We study the microbial growth responses underlying the CO2 pulse in short-term laboratory experiments. We further study how soil microbial responses change after repeated or more extensive drying-rewetting cycles.
Long-term consequences of drought and rewetting for microbial functioning
In this part of the project, we study the long-term consequences of changes in water availability for the composition and functioning of soil microbes. We will collect soils from long-term field experiments to study how the legacy of drought can modulate the microbial responses to additional drying-rewetting cycles as well as microbial functioning.