If, someday, future scientists discover life on Mars and look back to the string of events that had solidified their hope, they might just want to thank a tiny fungi from Antarctica.
We've come a long, long way since the discovery of liquid water on the red planet. It's all thanks to an ultra-hardy or cryptoendolithic fungi, which are typically found in the McMurdo Dry Valleys in the Antarctic Victoria Land. These organisms were gathered and sent by European scientists to the International Space Station for a special investigation.
After one year and six months of staying onboard the ISS, most of the fungi survived the Mars-like conditions on the space station. This discovery is particularly encouraging to experts, especially those who hope to find traces of past or current life on Mars.
Surviving Harsh Conditions
Rosa de la Torre Noetzel, co-researcher of the project and a scientist from Spain's National Institute of Aerospace Technology (NITA), said more than 60 percent of the cells of the crytpoendolithic fungi remained intact or stable even after exposure to Mars-like conditions.
De la Torre and other researchers from the University of Tuscany had harvested samples of the cryptoendolithic fungi found in the extreme – dry, frozen and wind-blasted – weather conditions of the McMurdo Dry Valleys, as well as durable lichens from other harsh environments.
The fungi were placed in cells that were 1.4 centimeters in diameter on a platform known as EXPOSE-E. This platform was specially developed by the European Space Agency to withstand extreme conditions. EXPOSE-E was sent through the space shuttle Atlantis to the space station and was placed outside the Columbus module with the help of an astronaut from the team led by Belgian scientist Frank de Winne.
For 18 months, the tiny fungi were exposed to an atmosphere with 95 percent carbon dioxide, 1.6 percent argon, 0.15 percent oxygen, 2.7 percent nitrogen, and 370 parts per million of H2O. The atmospheric pressure was 1,000 pascals.
Using optical filters, the tiny fungi were put under ultra-violet radiation as if they were on Mars, which had radiation higher than 200 nanometers. Others were subjected to lower radiation.
The study, which is featured in the journal Astrobiology, is part of an experiment called Lichens and Fungi Experiment (LIFE). The project has allowed scientists to study the fate of various communities of lithic organisms during a long-term voyage into space onboard the EXPOSE-E platform.
"The results help to assess the survival ability and long-term stability of microorganisms and bioindicators on the surface of Mars," says de la Torre, adding that the findings are fundamental and relevant for future experiments centered on the search of life on the red planet.
Another Collection of Lichen and Fungi Samples
Aside from the fungi from Antarctica, LIFE researchers also studied two species of lichens that have been collected from Spain and Austria. Half of these samples were also exposed to Mars-like conditions.
On the other hand, another group of lichen and fungi was exposed to extreme space environment, with temperature changes between +59.6 degrees Celsius or degrees Fahrenheit to -21.5 degrees Celsius or degrees Fahrenheit, a vacuum of 10-7 to 10-4 pascals, and radiation of up to 190 megagrays.
After 18 months, the two species that were "exposed to Mars" showed twice the metabolic activity of those that had been subjected to extreme space conditions. This indicated that the former had fared better than the latter.