We might not yet know if life exists on another planet, but the odds of it surviving on a barren, nutrient poor rock has just improved, as researchers have found that some microbes on Antarctica can live by effectively eating air.
Despite being located on a continent literally covered with water, the barren valleys and plains of Antarctica are actually extreme deserts and some of the driest places known on Earth. The extremely low humidity and frigid temperatures mean that very little can survive on the arid, rocky surface, leading many to consider these regions as a perfect analogue for other planets.
Yet life still finds a way. Some of the valleys are teaming with a diverse bunch of bacteria, all making a living in the seemingly inhospitable environment. “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,” explains Belinda Ferrari, who co-authored the study published in Nature, in a statement.
To understand how these microbes might be making their living, the Australian-based study took surface soil samples from two pristine ice-free deserts in eastern Antarctica, which to the naked eye look entirely devoid of life.
From these samples, they were then able to decode the genome from 23 microbes that were found living in the surface soil, including the genomes for two previously unknown bacteria called rather endearingly WPS-2 and AD3.
By trawling through the genetics of these hardy microbes, the scientists found hints as to their survival tactics. It turns out that these southern life forms show an unusually strong affinity for hydrogen and carbon monoxide, leading the researchers to conclude that the microbes can effectively feed off the molecules floating around them.
It is now thought that the air-munching microbes in Antarctica could give exobiologists an idea of what to look out for on other planets that might seem at first devoid of nutrients necessary to support life, with the most obvious candidate being Mars.
“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 Ferrari.
It seems that the chances of life sticking it out in other parts of the solar system may have just received a boost.
