Desert soil microbes adapt to thrive in extreme dry conditions

Desert soil microbes adapt to thrive in extreme dry conditions
by Robert Schreiber
Berlin, Germany (SPX) Apr 22, 2024

Scientists from the University of Vienna have shed light on how desert soil bacteria survive and thrive under the extreme conditions of prolonged droughts and intermittent heavy rainfall. Their findings, led by microbiologist Dagmar Woebken at the Centre for Microbiology and Environmental Systems Science (CeMESS), were recently detailed in Nature Communications.

Covering over 46% of the Earth's terrestrial surface, drylands are critical ecosystems that are expanding due to climate change and unsustainable land management. Below the sparse vegetation, a hidden network of microorganisms in the desert's biocrust contributes to soil health by enriching it with essential nutrients like carbon and nitrogen, helping to prevent erosion and retain water. The survival strategies of these microbes, particularly how they cope with the harsh dry conditions interspersed with rare rain, have been unclear until now.

The research reveals that desert soil bacteria remain dormant during droughts but swiftly activate during rare rainfall, undergoing a rapid "all-in" reactivation. Within minutes of moisture exposure, a significant portion of microbial diversity transitions from dormancy to activity. "When we simulate a rainfall event in the laboratory, we see that within the first 15 to 30 minutes, almost all taxonomic groups are activated," noted Dimitri Meier, co-first author of the study. This quick shift is critical for energy production and genome repair.

The study also employed innovative methods such as NanoSIMS, using stable isotope labeled water to track which bacteria assimilate heavy hydrogen atoms during simulated rain events. Stefanie Imminger, PhD candidate and co-first author, explained that while most biocrust cells reactivate with rainfall, only a few can grow, as rain episodes in deserts are typically very brief.

These insights highlight the resilience of desert soil bacteria, equipped to handle rapid changes in soil water content. This ability is pivotal not only for survival in deserts but might also offer lessons for microbial adaptation in other climates increasingly affected by drought due to climate change.

Research Report:Survival and rapid resuscitation permit limited productivity in desert microbial communities