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TOPIC: European Geosciences Union General Assembly 2012

Blobrana

Posts: 131433

Date: Apr 27 02:48 2012

Xanthoria elegans	Permalink

Title: Survival potential and photosynthetic activity of lichens under Mars-like conditions: a laboratory study. Authors: de Vera JP, Möhlmann D, Butina F, Lorek A, Wernecke R, Ott S. Lichens were repetitively exposed over 22 days to thermophysical Mars-like conditions at low-and mid-latitudes. The simulated parameters and the experimental setup are described. Natural samples of the lichen Xanthoria elegans were used to investigate their ability to survive the applied Mars-like conditions. The effects of atmospheric pressure, CO(2) concentration, low temperature, water availability, and light on Mars were also studied. The results of these experiments indicate that no significant decrease in the vitality of the lichen occurred after exposure to simulated martian conditions, which was demonstrated by confocal laser scanning microscopy analysis, and a 95% CO(2) atmosphere with 100% humidity, low pressure (partial pressure of CO(2) was 600 Pa), and low temperature has a balancing effect on photosynthetic activity as a function of temperature. This means a starting low photosynthetic activity at high CO(2) concentrations with Earth-like pressure has a reduction of 60%. But, if the simulated atmospheric pressure is reduced to Mars-like conditions with the maintenance of the same Mars-like 95% CO(2) concentration, the photosynthetic activity increases and again reaches similar values as those exhibited under terrestrial atmospheric pressure and concentration. Based on these results, we presume that, in any region on Mars where liquid water might be available, even for short periods of time, a eukaryotic symbiotic organism would have the ability to survive, at least over weeks, and to temporarily photosynthesise. Read more See also Expose-E experiment unit __________________

Blobrana

Posts: 131433

Date: Apr 26 08:48 2012

European Geosciences Union General Assembly 2012

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Press Conference 10
Habitable worlds in the Solar System

Live webcast

Is Earth alone in the Solar System in its ability to harbour life? Recent work has identified Jupiter's system as comprising potentially habitable worlds, including on one of its moons, Europa, which contains 'shallow lakes' and other physical features analogous to areas on Earth, in addition to its global ocean. In fact, a mission to the Jupiter system, which will characterise the conditions that may have led to the emergence of habitable environments among the Jovian icy satellites, is under study. It pays special emphasis on the three ocean-bearing worlds, Ganymede, Europa, and Callisto. Another team has found that some microorganisms on Earth may be able to survive in the harsh conditions of open space or possibly even in environments similar to the Martian surface. In the Saturn system, evidence is mounting for a liquid water ocean in the deep interior of Titan, in addition to its surface seas of liquid methane and ethane. Coupled with additional discoveries by the Cassini spacecraft, which strengthen the case for liquid water in Saturns moon Enceladus, the argument for life elsewhere in the Solar System seems all the more compelling.

Participants:

Jean-Pierre Paul de Vera, Researcher, German Aerospace Center (DLR), Institute of Planetary Research, Berlin, Germany

Britney Schmidt, Research Scientist, Dawn Mission Science Team EPO Liaison, Institute for Geophysics, University of Texas

Michele Dougherty, Professor of Space Physics, Imperial College London, London, UK and Science Lead on the Study Team for ESAs JUICE mission

Jonathan Lunine, Professor, Space Sciences Building, Cornell University, Ithaca, New York, USA

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