WinMicAct · Windows of microbial activity in deserts afforded by non-rain water

Soil microorganisms are essential drivers of ecosystem processes in drylands that cover ~40% of the Earth’s landmasses. It is widely accepted that microbial activity in arid deserts is confined to rare, short and unpredictable rain pulses. Yet, water could be available for soil microorganism by other processes, such as dew formation, fog deposition and water vapor adsorption. These so-called non-rain water inputs represent significant sources of water, as they are more frequent and reliable. Yet, it is unknown if desert soil microorganism can utilize these water sources for reactivation, nor the associated microbial activities they facilitate and their overall contribution to microbial-driven ecosystem processes.WinMicAct will challenge the rain-centered view of desert microbial activity. I hypothesize that desert microbial communities can use the minute water input provided by non-rain water for reactivation. WinMicAct pushes the boundaries of molecular omics and microbial activity analysis to detect reactivation down to the lowest possible water availabilities. Utilizing spatial upscaling, WinMicAct will estimate the contribution of these microbial activities (respiration, CO2 and N2 fixation) to the ecosystem level. WinMicAct will further reveal the importance of different water sources for survival and thus maintaining desert soil biodiversity that is crucial for ecosystem functioning. Finally, WinMicAct is highly relevant in light of climate change, as future scenarios predict changing patterns of rain and non-rain water inputs. With the knowledge gained in this project on microbial processes driven by the different water sources under climate change predictions, WinMicAct provides the foundation for future investigations and modeling of climate change effects on dryland ecosystem processes. Together, WinMicAct will generate ground-breaking knowledge on non-rain water driving microbial activities and will be a major step forward in arid ecosystem research.