Researchers from Jagiellonian University and the Space Research Centre of the Polish Academy of Sciences in Wrocław have tested the possibility of two lichen species functioning in an environment similar to the surface of Mars. Their findings challenge previous assumptions about the inhospitable nature of the Red Planet for life.
Lichens are specific symbiotic organisms consisting mainly of fungi and photosynthetic partners, which can be eithe autotrophic algae or cyanobacteria. Compared to typical fungi, they have many peculiar features, such as highly variable morphology, specific metabolic pathways, and unique reproductive methods. Lichens are found in virtually everywhere on Earth, from the poles to the tropics, but only in the most extreme environments, such as hot and dry deserts, polar regions, or high mountains, do they become a significant element of the ecosystem. Due to their ability to adapt and survive, lichens have become a major focus of astrobiologists who speculate whether they could survive in extraterrestrial environments, such as outer space or the surface of Mars.
Ph: Pixabay
The results of experiments conducted under the direction of Dr hab. Kaja Skubała, prof. UJ from the JU Faculty of Biology. The new study challenged previous assumptions about the wholly inhospitable nature of Mars, while providing insights into astrobiology and space exploration.
For the first time, scientists verified the possibility of two species of lichens, Diploschistes muscorum and Cetraria aculeata, functioning in a metabolically active state in an environment similar to that on the surface of Mars. Both organisms were placed in a specially prepared vacuum chamber, where conditions of the Red Planet were simulated for 5 hours. The lichens had to withstand, among other things, temperature fluctuations and X-ray radiation.
Experiments showed that Diploschistes muscorum is capable of carrying out metabolic processes and effectively activating defence mechanisms, and it withstands an X-ray dose of 50 Gy, which is expected on the surface of Mars during one year of high solar activity. Thus, high doses of ionising radiation associated with solar flares and energetic particles reaching the surface of Mars should not affect the potential ability of lichens to live on this planet.
The presented results expand knowledge about biological processes in conditions simulating those on Mars and show the physiological and biochemical response of hydrated organisms to ionising radiation – one of the key factors limiting the possibility of survival and ability to live on the surface of this planet. They also contributed to expanding knowledge about the adaptation of lichens and their potential to colonise extraterrestrial environments.
Understanding the limits of life and the possibility of its existence beyond Earth is one of the fundamental goals of astrobiology. Mars is a leading candidate for searching for signs of life and potential colonization by Earth-based life forms. The study identified Diploschistes muscorum as a promising candidate for further astrobiological research, scientists suggest.
The results were published in IMA Fungus, the flagship journal of the International Mycological Association.
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