Scientists have discovered some extremophile microbes in the Antarctic desert surface soils that can survive solely on air. Without energy derived geothermally or from photosynthesis the robust microbes persist based upon a previously unknown ability to scavenge from atmospheric gases.
“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 study senior author and UNSW scientist Associate Professor Belinda Ferrari.
Dr. Ferrari and her team’s findings, which have been published recently in Nature, have implications for life on other planets and suggests that extra-terrestrial microbes could also rely on trace atmospheric gases for their survival. They found a microbial ability to scavenge hydrogen, carbon monoxide and carbon dioxide from the air.
"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," she says.
Adam's Flat Antarctica. One sample site in eastern Antarctica. Photo Credit: Phil Obrien
The team sampled soils from pristine polar deserts devoid of any vascular plants from two coastal ice-free sites in different regions of eastern Antarctic. Site One was Robinson Ridge, 10 kilometres from Casey Station, in Wilkes Land and the second other was Adams Flat, 242 kilometres from Davis Station in Princes Elizabeth Land. Isolating the microbial DNA from the surface soils they used shotgun sequencing to reconstruct the genomes of 23 microbes that resided there. This included two new groups (phyla), called WPS-2 and AD3. These dominant community members coded and expressed genes for hydrogenases, carbon monoxide dehydrogenases, and a RuBisCO lineage known to support chemosynthetic carbon fixation. These genes and their expression allowed the microbes to anaerobically scavenge at a rate to maintain their theoretical energy needs and support primary production.
Although more work across different ecosystems across the globe among other oligotrophic habitats, the results from this study provides a new baseline for understanding the minimal requirements to sustain life. This is a very exciting start and possibly a jumping off point for searching for life on other planets.
For this interesting article please see:
https://www.nature.com/articles/nature25014
Ji M, Greening C, Vanwonterghem I, Carere CR, Bay SK, Steen JA, Montgomery K, Lines T, Beardall J, van Dorst J, Snape I, Stott MB, Hugenholtz P and Ferrari BC (2017) Atmospheric trace gases support primary production in Antarctic desert surface soil. Nature. 552, 400–403 - doi:10.1038/nature25014
