In a new study, researchers conducted DNA-based analyses to confirm the high abundance of bacterial life in the Atacama Desert, one of the most inhospitable environments.
The Atacama Desert in Chile is one of the oldest and driest deserts on Earth. Its extreme aridity makes it nearly impossible for any life to thrive. Yet the study published in Applied and Environmental Microbiology reveals the existence of active microbial colonization.
“Microbes are the pioneers colonizing this kind of environment and preparing the ground for the next succession of life,” Wagner said.
As these microbes could be considered pioneer species, they could have implications on new landforms formed by earthquakes or landslides. Therefore, studying their functions in habitats is vital.
An international team of researchers has utilized a new separation technique to focus on the microbial life in low-biomass. This technique separates extracellular (eDNA) from intracellular (iDNA) genetic material, which was not possible with conventional DNA extraction methods.
Most of the commercially available DNA extraction tools leave a mixture of living, dormant, and dead cells from microorganisms. However, specific metagenomic sequencing requires good quality of DNA.
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“If you extract all the DNA, you have DNA from living organisms and also DNA that can represent organisms that just died or that died a long time ago,” says Wagner.
To overcome this issue, researchers developed a process for filtering intact cells from the mixture. Filtering intact cells from the mixture extracts eDNA genetic fragments from the cells. This enabled researchers to group all DNA samples into two different classes: eDNA and iDNA.
They tested this approach on soil samples collected from the Atacama Desert. It revealed diverse living and possibly active microbes in the most arid areas, including Actinobacteria and Proteobacteria.
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Intriguingly, samples collected from depths of less than 5 centimeters revealed that Chloroflexota bacteria dominated in the iDNA group. This means that the microbes are active and constant turnovers are taking place.
“If a community is really active, then a constant turnover is taking place, and that means the 2 pools should be more similar to each other,” says the study.
These results show specialized microorganisms that thrive in unfavorable conditions to facilitate the next succession.
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Journal Reference
- Bartholomäus A, Genderjahn S, Mangelsdorf K, Schneider B, Zamorano P, Kounaves SP, Schulze-Makuch D, Wagner D.0.Inside the Atacama Desert: uncovering the living microbiome of an extreme environment. Applied and Environmental Microbiology. DOI: 10.1128/aem.01443-24
