Researchers have found a new type of microbe that can survive on air alone – and say it could change the way we hunt for alien life.
The microbe can scavenge hydrogen, carbon monoxide and carbon dioxide from the air to stay alive in extreme conditions.
It is the first time the behaviour has been seen, and most organisms use energy from the sun or the earth to grow.
UNSW-Sydney led scientists have discovered that microbes in Antarctica have a previously unknown ability to scavenge hydrogen, carbon monoxide and carbon dioxide from the air to stay alive in the extreme conditions.
‘Here we provide evidence that atmospheric trace gases are the primary energy sources of two Antarctic surface soil communities,’ researchers wrote in Nature.
‘We propose that atmospheric H2, CO2 and CO provide dependable sources of energy and carbon to support these communities, which suggests that atmospheric energy sources can provide an alternative basis for ecosystem function to solar or geological energy sources.’
‘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,’ said study senior author and UNSW scientist Associate Professor Belinda Ferrari.
The find has implications for the search for life on other planets, suggesting extra-terrestrial 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, Ferrari said.
‘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.
Researchers at UNSW, Monash University, the Australian Centre for Ecogenomics at the University of Queensland, GNS Science in New Zealand, and the Australian Antarctic Division, worked on the study, which is published in the journal Nature.
Soil samples were collected from two coastal ice-free sites in different regions of eastern Antarctica.
One was Robinson Ridge, 10 kilometres from Casey Station, in Wilkes Land.
The other was Adams Flat, 242 kilometres from Davis Station in Princes Elizabeth Land.
‘Both areas are pristine polar deserts devoid of any vascular plants,’ says Associate Professor Ferrari, of the UNSW School of Biotechnology and Biomolecular Sciences.
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 which 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,’ said Ferrari.
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, the scientists say.
