Whether anything ever lived on Mars is unknown. And the present environment, with harsh temperatures, intense radiation, and a sparse atmosphere, isn’t exactly propitious for life. Despite the red planet’s brutality, lichens that inhabit some of the harshest environments on Earth could possibly survive there.
Lichens are symbionts, or two organisms that are in a cooperative relationship. There is a fungal component (most are about 90 percent fungus) and a photosynthetic component (algae or cyanobacteria). To see if some species of lichen had what it takes to survive on Mars, a team of researchers led by botanist Kaja Skubała used the Space Research Center of the Polish Academy of Sciences to expose the lichen species Diploschistes muscorum and Cetrarea aculeata to simulate Mars conditions.
“Our study is the first to demonstrate that the metabolism of the fungal partner in lichen symbiosis was active while being in a Mars-like environment,” the researchers said in a study recently published in IMA Fungus. “X-rays associated with solar flares and SEPs reaching Mars should not affect the potential habitability of lichens on this planet.”
Martian ionizing radiation is threatening to most forms of life because it can cause damage at the cellular level. It can also get in the way of physical, genetic, morphological, and biochemical processes, depending on the organism and radiation level.
Going to extremes
Lichens have an edge when it comes to survival. They share characteristics with other organisms that can handle high levels of stress, including a low metabolism, not needing much in the way of nutrition, and longevity. Much like tardigrades, lichens can stay in a desiccated state for extended periods until they are rehydrated. Other lichen adaptations to extreme conditions include metabolites that screen out UV rays and melanin pigments that also defend against radiation.