IAFE   05512
INSTITUTO DE ASTRONOMIA Y FISICA DEL ESPACIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Hypersaline enviroments as planetary analogs
Autor/es:
ABREVAYA, X.C.
Reunión:
Simposio; Primer Foro Internacional de Geobiologia; 2016
Resumen:
The presence of evaporitic enviroments on Mars was evidenced during the last years through the dataobtained from measurements on this planet [1-7]. Additionally, as part of these environments, thereare several evidences that support the existence halites on Mars (NaCl evaporitic minerals). Theevaporation of brine pockets is one of the hypothesis to explain the formation of halites on thisplanetary body and halite inclusions in the SNC meteorite Nakhla are a mineralogical evidence of thepresence of halites on Mars, because of its pre-terrestrial origin [8,9]. On Earth, extremophilicmicroorganisms that live at very high salt concentrations known as halophilic archaea were foundentrapped inside ancient halites in evaporitic deposits from 250 Mya [10,11]. These microorganismswere proposed as possible life forms on Mars and possible candidates for the interplanetary transferof life [12]. All this evidences open the possibility of an extraterrestrial origin of life on the Earth,considering the Lithopanspermia hypothesis (interplanetary transfer of life through meteorites). Infact, in previous works performed at the TGM beamline (LNLS, Brazil), we showed that some speciesof microorganisms are capable to survive to several doses of VUV radiation (57.5?124 nm) andvacuum as those related to the conditions of the interplanetary space [13,14]. We expanded theseexperiments in this work, analyzing the survival of microorganisms entrapped in halites undersimulated Martian (-80ºC, 8 mbar, 95%CO2:5%N2) conditions in a Martian simulation chamber. Theentrapped microorganisms were then exposed to VUV radiation up to 40000 Jm-2 and vacuum (10-4Pa) (TGM beamline, LNLS, Brazil) as those found during an interplanetary travel. The results are inagreement with our previous works that show that the survival of the microorganisms is dependenton the specie. This is the first experiment on the survival of microorganisms subjected to a simulatedentrapment in halites under Martian simulated conditions, and therefore, the first time that a simulatedinterplanetary travel test these conditions.