Living on thin air – microbe mystery solved

7 Dec 2017

image of Robinson Ridge in AntarcticaAustralian 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.

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.

University of Queensland School of Chemistry and Molecular Biosciences ARC Laureate Fellow Professor Phil Hugenholtz said the study highlighted how much was still to be learned about uncultured microorganisms, which still comprise the bulk of microbial diversity on the planet.

Professor Hugenholtz is also director of UQ’s Australian Centre for Ecogenomics and affiliated with the Institute for Molecular Bioscience.

Study senior author and UNSW scientist Associate Professor Belinda Ferrari said Antarctica was 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,” she says.

“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.”

Soil samples were collected from two pristine, polar desert, 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.

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 giving 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.

The Australasian-based study, by researchers at UNSW, Monash University, the Australian Centre for Ecogenomics, GNS Science in New Zealand, and the Australian Antarctic Division, is published in the journal Nature (doi:10.1038/nature25014).