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Atmospheric Gases Enough to Support Life

Scientists have discovered that microbes in Antarctica can scavenge hydrogen, carbon monoxide and carbon dioxide from the air to stay alive in the extreme conditions. The revelation has implications for the search for life on other planets, as it suggests that extraterrestrial microbes could also rely on trace atmospheric gases for survival.

“Antarctica is one of the most extreme environments on Earth. Yet the cold, dark and dry desert regions are home to a surprisingly rich diversity of microbial communities,” says the study’s senior author A/Prof Belinda Ferrari of the UNSW School of Biotechnology and Biomolecular Sciences.

“The big question has been how the microbes can survive when there is little water, the soils are very low in organic carbon and there is very little capacity to produce energy from the sun via photosynthesis during the winter darkness. We found that the Antarctic microbes have evolved mechanisms to live on air instead, and they can get most of the energy and carbon they need by scavenging trace atmospheric gases, including hydrogen and carbon monoxide,” Ferrari says.

The Australasian-based study, by researchers at UNSW, Monash University, The University of Queensland, GNS Science in New Zealand and the Australian Antarctic Division, has been published in Nature.

Soil samples were collected from two coastal ice-free sites in different regions of eastern Antarctica. One was Robinson Ridge, 10 km from Casey Station. The other was Adams Flat, 242 km from Davis Station. “Both areas are pristine polar deserts devoid of any vascular plants,” Ferrari says.

The researchers studied the microbial DNA in the surface soil from both sites and reconstructed the genomes of 23 of the microbes that lived there, including some of the first genomes of two groups of previously unknown bacteria called WPS-2 and AD3. They found the dominant species in the soils had genes that gave them a high affinity for hydrogen and carbon monoxide, allowing them to remove the trace gases from the air at a high enough rate to sustain their predicted energy needs and support primary production.

“This new understanding about how life can still exist in physically extreme and nutrient-starved environments like Antarctica opens up the possibility of atmospheric gases supporting life on other planets,” Ferrari says.

Most organisms use energy from the sun or the earth to grow. The scientists say that more research is needed to see if this novel use of atmospheric gases as an alternative energy source is more widespread in Antarctica and elsewhere.