Deep Microbial Biosphere Discovered Beneath Atacama Desert

Context

New research has found a rich microbial biosphere buried 13 feet (4 meters) beneath the hot surface of the Atacama Desert in Chile. 

Microbial Life Thrives in Atacama Desert’s Extreme Conditions

• Discovery of Isolated Bacterial Community in Yungay Valley: A team of researchers discovered a resilient group of bacteria thriving in the extreme bone-dry Yungay Valley. 
  • This microbial community is completely isolated from the surface world.
  • The researchers’ findings represent the deepest microbial survey and discovery of microbial life in Atacama soil.

Key Findings of Research:

• Microbial Resilience in Atacama Desert’s Extreme Conditions: Higher forms of life struggle to survive in the super-arid conditions in the Atacama Desert. 
  • Despite the rough environment, microbial life thrives in the salty and sulfate-rich soil in the desert. 
• Microbial Presence in Atacama Desert Soil Depths: Microbes have been previously documented in the desert region as deep as 2.6 feet (80 centimeters). 
  • The researchers have now discovered that microbial life extends from depths of 6.6 feet (2 meters) to at least 13 feet (4 meters) deep down below the surface of the desert. 
• Microbial Diversity Across Atacama Desert Sediment Depths: In the upper 2.6 feet (80 centimeters) of playa sediments, firmicute phylum microbes were prevalent which are resistant to high salt content and can thrive in less oxygen.
  • Below 6.6 feet, the scientists observed a distinct microbial population dominated by Actinobacteria which live in harsh environments, including the Arctic and other salty habitats.

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• Colonization and Burial of Actinobacteria in River Deposits: The team suggests Actinobacteria colonized the river deposits around 19,000 ago and became buried beneath playa sediments over thousands of years. 
• Microbial Survival Mechanism: The microbes survive at depth by extracting water from gypsum, which forms when the mineral anhydrite is exposed to water. 
  • This reaction is reversible at high temperatures, which could release water within Atacama soils.
• Significance of Study:  The Atacama desert is often used as an analog for studying the harsh conditions of Mars, where the surface is completely lifeless, but may hide evidence of microbial life below. 
  • The new research could inform the search for life on Mars which also has gypsum deposits. This could potentially serve as a water source for extraterrestrial life.

Atacama Desert

• About: It is known as Earth’s driest hot desert located in northern Chile. It forms a continuous strip for nearly 1,000 km along the narrow coast of Chile.  
  • It is a sparsely populated and rainless plateau, running east from the Pacific Ocean to the Andes Mountains. 
• Flora: The only plants characteristic of the sandy expanses are bromeliads, which are fed almost exclusively by the fog. 
• Fauna: Important species include scorpions and insects,  Darwin’s leaf-eared mouse or a South American gray fox. 
• Protected Area: Pan de Azúcar National Park expands northward to protect the region’s high levels of endemism, especially its plants. 

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