Last updated December 7, 2017 at 10:36 am
“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.
“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.”
The research team took samples from two 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.
It’s notoriously difficult to culture bacteria from soil samples. Instead, the researchers used a method called Shotgun Metagenomic Sequencing, a relatively new technique using sequencing and computation to analyse all the genes and microbes from any environmental sample. They 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.
Primary producers in an ecosystem are able to produce energy from non-living sources. Algae or plants turn sunlight into usable energy in the form of organic molecules (photosynthesis). There are microbial communities around hot hydrothermal vents in the dark ocean that can form organic molecules from inorganic starter molecules. This study demonstrated that the bacteria found in the Antarctic soil act as primary producers, having evolved mechanisms to live on air instead.
“They can get most of the energy and carbon they need by scavenging trace atmospheric gases, including hydrogen and carbon monoxide,” says Associate Professor Ferrari.
“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,” says Associate Professor 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.
The research was published in Nature.