Survival of lichens on Mars

Abstract

On the surface of Mars several main aspects in combined form are conditioning the existence of life: temperature, humidity, pressure, composition of the atmosphere and radiation. The Earth also presents very dry and/or cold environments, which are close to Martian surface conditions with a high UV radiation. Due to the inability to test the survival capacity of extremely resistant organisms that live on these analog Mars environments, which are referred as extremophiles and extreme tolerant, climatic chambers that mimic the Mars climatology have been used. In this work we report the results obtained with the extreme tolerant lichen species Cicinaria gyrosa exposed at PASC (Planetary Atmospheric Surface Chamber, INTA, CAB) to Mars simulated parameters, that is, to a Mars atmospheric composition of mainly 95% of CO2 and a pressure of 7 mbar, to UV-solar radiation at Mars surface (>200 nm) and to a temperature of -93 ºC, in combined- and independent form, in order to obtain a deeper understanding of the individual and joint effects. The results obtained have demonstrated an extremely high resistance of this lichen species against Mars simulated environmental conditions.