Wöbken, Dagmar

More than 40 percent of the world's land area is covered by arid regions. However, climate change and unsustainable agriculture are causing this proportion to grow steadily. In these extreme habitats, soil microorganisms adapted to the desert climate perform key ecological functions. Microbes on the soil surface – in the so-called biological soil crust – are particularly important, as they supply carbon and nitrogen, two key factors for soil fertility. They also help to store water and prevent soil erosion.

Until now, it has been assumed that microbial activity in dry deserts is limited to rare, short, and unpredictable rainfall. Other water sources found in the desert, namely fog, dew, and water vapor adsorption, have not been the focus of attention. “These are more common than rain in many deserts and are therefore more reliable sources of water. However, it is hardly known whether microorganisms can use these water sources for reactivation. The associated microbial activities and their overall contribution to microbially controlled ecosystem processes are also largely unknown,” explains microbiologist Dagmar Woebken.

In their ERC-funded research project WinMicAct, Woebken and her team will investigate the importance of these so-called non-rainwater inputs for microbial activities and the maintenance of microbial diversity. Through spatial upscaling – i.e., scaling up to the ecosystem level – the contribution of these activities will be estimated in comparison to rain-driven activity. All this will be made possible by a multidisciplinary approach and in collaboration with scientists at the University of Graz, in Israel, and Spain. In addition, the project will take into account changes in the pattern of rain and non-rainwater inputs expected as a result of climate change, thus laying the foundation for future studies and modeling of the effects of climate change on ecosystem processes in arid regions.