Impact of UV C exposure on the water retention of the lichen Buellia frigida

New results on extremophiles and observations of Mars missions regarding the detailed mineralogy, the occurrence of water in the equatorial region of Mars [1-3], new announcements of MSL findings and their implications for the surface condi-tions at Gale crater [4, 5] as well as measurements of the Mars surface radiation environment [6] fuel the debate about possible developments of life on Mars. Based on previous studies [7-8] we examined water vapor interaction and water-bearing properties of B. frigida before and after UVC irradiation. The meas-urements have been partially conducted after simula-tion of environmental conditions which are supposed to be Mars-like. Lichens are symbiotic organisms that are able to colonize a broad range of extreme habitats and, therefore, represent useful model systems in as-trobiological research. Our aim is to contribute to an improved under-standing of extremophiles under exobiological aspects within the frame of BIOMEX (Biology and Mars Ex-periment) at the ISS, in respect to irradiation effects on water retention properties. The results may also sup-port data evaluation of in-situ missions such as MSL and ExoMars. References: [1] Feldmann W.C. et al. (2004) JGR 109 E 09006. [2] Bibring, J.-P. et al. Science 307, 1576-1581. [3] Poulet F. et al. (2005) Nature 438, 623- 627. [4] Vaniman D.T. et al. (2013) Science DOI: 10.1126/science.1243480. [5] Ming D.W. et al. (2013) Science DOI: 10.1126/science.1245267 [6] Hassler D.M. et al. (2013) Science DOI: 10.1126/science. 1244797.[7] Jänchen J. et al. (2006) Icarus, 180, 353- 358. [8] Jänchen J. et al. (2013) 44th LPSC Abstract No. 1504