Microbial growth under drought is confined to distinct taxa and modified by future climate conditions

Droughts are expected to get more frequent and intense with climate change, threatening soil health across the globe. Microbial activities in soil control important transformation processes such as carbon loss or nutrient cycling, yet, quantifying their response to drought is hampered by methodological limitations. Here, we used a novel approach combining 18O water vapor equilibration and quantitative stable isotope probing (vap-qSIP) to quantify bacterial and archaeal growth under drought and in combination with simulated future climate conditions (+ 3C warming, + 300 ppm atmospheric CO2). These results provide first insights into the growth patterns of bacteria and archaea in drought-exposed soils and suggest that future climate conditions modify their drought response. Sequencing was performed at the Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna under the project IDs JMF-2104-06 and JMF-2012-8.