High Survival Capacities of Lichens on Space Exposure Experiments: a Signature for Pre-Adaptation to Space?

Kurzfassung

During the last years many experiments has been performed and are actually still in progress with lichens under simulated and real space experiments (de Vera et al. 2003, 2004a,b, 2008; de la Torre et al. 2004, 2007; Sancho et. al. 2007). A highly resistance and survival potential has been confirmed by analysis on photosynthesis activity, microscopic verifications and germination and growth capacity studies as well as by physiology tests using different fluorescence detection methods before, partially during (de Vera et al. 2009) and after space simulation and real space exposure (Sancho et al. 2007). According to the results we got by the space experiment on BIOPAN 6, we can suggest that the microorganisms might have reached pre-adapted stages during evolution which allows the high significant survival capacity during exposure to space parameters as there are UVradiation, ionizing radiation and vacuum. We have to emphasise that the investigated organisms reached a certain level of resistance in their habitats. They live on the surface of the Earth, governed by intense UV radiation, desiccation periods and large temperature fluctuations. But comparisons between radiation profiles on terrestrial habitats of lichens with radiation profiles under simulated and real space parameters seem actually not show clear correlations. This means, that especially the radiation income on the investigated natural habitats of lichens is not any way close to radiation intensity and doses which have been measured in space. You need approximately 15 000 years of continuously UV irradiation with daily doses as measured in their habitat to get the radiation doses as it has been measured on BIOPAN 6 during 10 days of exposure in space. The question arises, why the microorganisms had developed some very efficient shielding strategies or probably repair mechanisms to space environmental conditions, while in their natural habitat there was no necessity to develop such highly efficient adaptation strategies because no similar extreme space radiation doses profile has been observed in their natural environment. Might the answer be found in the history of the evolution of life?