The Lively Subterranean Scene of the Atacama Desert
Underground Ecosystem Unearthed in Earth's Driest Sahara Desert
In the barren, largely vacant expanse of the Atacama Desert in northern Chile - a location known for its exceptional earth-based telescopes - lies a hidden multitude of life beneath the surface, a recent study reveals.
Scientific endeavors have previously discovered microbial life beneath the desert's surface, but the latest research unveils the astonishing diversity of these inhabitants. The team behind this intriguing discovery delved as deep as 4.2 meters in the Yungay region of the Atacama, unearthing a variety of microbial communities across different soil types and depths. Published this week in PNAS Nexus, their findings have piqued scientific curiosity once more.
What lies beneath the arid expanse encompasses a myriad of life forms, encompassing cyanobacteria and sturdy Actinobacteriota, as well as nitrogen-fixing Alphaproteobacteria. According to the researchers, gypsum crystals act as a protective microclimate, shielding microbes from harmful UV radiation while enabling them to carry out photosynthesis through filtered light.
High salt concentrations appear to halter microbial colonization in the lower parts of the playa sediments; however, regions beneath alluvial fan deposits demonstrate the resilience of microbial communities due to the gypsum's potential to provide an alternative water source.
The Atacama Desert registers minimal water yearly, and a four-year study conducted during an El Niño event, which brought heavy rainfall to neighboring regions, only resulted in a single rain event within the valley, equating to .091 inches (2.3 millimeters). The research team proposes that resemblant gypsum deposits found on Mars could offer a potential water source for any microbial life residing on the Red Planet.
Although NASA has attempted to penetrate the Martian surface before and the Perseverance rover has harvested a trove of intriguing rock samples, no mission has drilled as deep as the researchers did in the Atacama. The desert's forlorn landscape serves as an analog for Mars, and if life can thrive beneath its arid surface, it raises the possibility that similar circumstances may foster life on Mars as well.
"Even though gypsum may not be common in the subsurface of all deserts, the presence of this subterranean niche could indicate that desert biodiversity has been previously underestimated, and that under certain circumstances, a microbial community can persist in the deeper layers of the driest places on Earth," the team wrote.
Defying the trend of upwardly inclined science in the Atacama, this study offers a fresh perspective on the teeming life eking out survival in its desolate, yet somehow familiar, terrain.
Additional Reading: Deepest Virus Ever Detected Unearthed by Scientists in the Mariana Trench
Noteworthy Tidbits:
- Deserts like the Mojave, Sonora, Gobi, Negev, Namib, and Atacama boast diverse microbial communities that have evolved to thrive in harsh environments.
- These communities exhibit adaptive traits such as slow reproduction cycles and mechanisms to protect against solar radiation, as well as metabolic diversity, specializing in processes like carbon, iron, and sulfur fixation.
- Deep soil layers in deserts, including the Atacama, remain sparsely explored but contain numerous microbial communities with unique metabolic capabilities, like the CSP1-3 phylum, essential for carbon, nitrogen, and sulfur cycling.
- While the Atacama Desert presents extreme conditions, its microbial diversity comparatively mirrors other desert regions, allowing life to subsist even in energy-limited environments.
- The echoes of microbial life in the Atacama Desert suggest that Earth's deserts, such as the Mojave, Gobi, Negev, Namib, and Sonora, may harbor more diverse communities than previously estimated, given their shared ability to thrive in harsh environments.
- In the hidden depths of these desert substrata, communities with adaptive traits including slow reproduction cycles, radiation protection mechanisms, and metabolic diversity may be present, specializing in processes like carbon, iron, and sulfur fixation.
- Deep soil layers in deserts like the Atacama remain largely unexplored, yet they contain numerous microbial communities with unique metabolic capabilities, such as the CSP1-3 phylum, vital for carbon, nitrogen, and sulfur cycling.
- As new technological advancements propel humanity's exploration of Mars, the extremophile microbial communities unveiled in Earth's deserts offer promising insights, suggesting that these microorganisms could potentially persist beneath the Martian surface under similar conditions.
