The Atacama Desert, stretching along the Pacific Coast in Chile, holds the title of the driest place on Earth. Its extreme aridity makes it inhospitable to most forms of life. However, recent studies of the desert's sandy soil have revealed thriving microbial communities.

A new study offers exciting insights into these microbes and may even have implications for exploring life on other planets.

New Technique to Identify Living Microbes

In the latest issue of Applied and Environmental Microbiology, researchers describe a groundbreaking technique to differentiate between genetic material from living and dead cells in the Atacama's soil. Traditional DNA extraction methods couldn't separate this genetic material, often mixing DNA from both living and dead organisms. The new method developed by Dirk Wagner, Ph.D., and his team at the GFZ German Research Centre for Geosciences in Potsdam, allows for a more precise study of living microbial communities in low-biomass environments.

Insights from Atacama Soil

The researchers applied their new method to soil samples from a west-to-east stretch of the Atacama Desert, ranging from the ocean's edge to the foothills of the Andes. The results revealed a wide range of living, possibly active, microbes. Wagner emphasizes the significance of understanding the relationship between eDNA (extracellular DNA) and iDNA (intracellular DNA) for studying microbial processes. This method, Wagner says, could also be applied to environments formed after natural disasters, such as earthquakes or landslides, where life is beginning to colonize.

The Role of Microbes in Harsh Environments

Wagner explains that microbes are crucial pioneers, preparing the ground for future life. Understanding their processes could help scientists uncover microbial behavior in other extreme environments, such as Mars or other planets. The ability to separate living from dead microbial DNA also offers more accurate data for metagenomic sequencing, a tool that helps identify specific microbes and their roles in the ecosystem.

A Revolutionary Approach for Low-Biomass Environments

Wagner and his team's technique addresses the challenges of extracting good-quality DNA from low-biomass environments like the Atacama Desert. Traditional methods often yield a mix of DNA from living, dormant, and dead organisms, making it difficult to identify which microbes are actively engaged in microbial processes. By using their new filtering method, the team successfully separated eDNA from iDNA, providing clearer insights into active microbial life.

Microbial Communities in Atacama Soil

The new approach revealed that both Actinobacteria and Proteobacteria were present in the soil samples, with consistent turnover between living and dead cells. Chloroflexota bacteria dominated in the iDNA group in samples from depths of less than 5 centimeters. These findings confirm that microbial communities in the Atacama are constantly evolving and active, despite the harsh environmental conditions.

Next Steps in Microbial Research

Looking ahead, Wagner plans to conduct metagenomic sequencing on the iDNA samples to delve deeper into the specific microbes and processes at play in the Atacama Desert. This approach could also be applied to other challenging environments on Earth—and even beyond our planet—offering new opportunities for studying microbial life in space exploration.

Through this innovative method, researchers are now able to gain deeper insights into the active microbial communities of Earth's most extreme environments, with exciting possibilities for further exploration.