Interplanetary transfer of photosynthesis: an experimental demonstration of a selective dispersal filter in planetary island biogeography.

We launched a cryptoendolithic habitat, made of a gneissic impactite inoculated with Chroococcidiopsis sp., into Earth orbit. After orbiting the Earth for 16 days, the rock entered the Earth's atmosphere and was recovered in Kazakhstan.

Stratified response to environmental stress in a polar lichen characterized with FT-Raman microscopic analysis.

The role of Antarctic epilithic lichens in the primary colonization of rocks and in the formation of soils is receiving attention because of the production of the stress-protective biochemicals needed to combat radiation, desiccation and extremes of temperature. Raman microscopy has been used here to study the encrustations produced at the interface between the rock substratum and Buellia spp. lichen thalli; in addition to whewellite, calcium oxalate monohydrate, the presence of weddellite, the metastable dihydrate form, was confirmed in the encrustations.

Why Raman spectroscopy on Mars?--a case of the right tool for the right job.

We provide a scientific rationale for the astrobiological investigation of Mars. We suggest that, given practical constraints, the most promising locations for the search for former life on Mars are palaeolake craters and the evaporite deposits that may reside within them. We suggest that Raman spectroscopy offers a promising tool for the detection of evidence of former (or extant) biota on Mars.

Non-destructive analysis of pigments and other organic compounds in lichens using Fourier-transform Raman spectroscopy: a study of Antarctic epilithic lichens.

Lichens in Antarctic habitats are subjected to environmental extremes, including UVB radiation, desiccation and low temperatures, as well as to rapid fluctuations in these. Lichens synthesise a variety of chemical compounds in response to their environmental conditions which contribute towards their colour, and which act as protectants against physiological stresses. The fluorescence generated by the lichens at 532 nm can be used in epifluorescence microscopy to identify their presence on substrata but this can severely affect the Raman spectra using visible excitation.

Raman spectroscopic detection of biomolecular markers from Antarctic materials: evaluation for putative Martian habitats.

The vital UV-protective and photosynthetic pigments of cyanobacteria and lichens (microbial symbioses) that dominate primary production in Antarctic desert ecosystems auto-fluoresce at short-wavelengths. A long wavelength (1064 nm) near infra-red laser has been used for non-intrusive Raman spectroscopic analysis of their ecologically significant compounds. There is now much interest in the construction of portable Raman systems for the analysis of cyanobacterial and lichen communities in the field; to this extent, Raman spectra obtained with laboratory-based systems operating at wavelengths of 852 and 1064 nm have been evaluated for potential fieldwork applications of miniaturised units.

Brines in seepage channels as eluants for subsurface relict biomolecules on Mars?

Water, vital for life, not only maintains the integrity of structural and metabolic biomolecules, it also transports them in solution or colloidal suspension. Any flow of water through a dormant or fossilized microbial community elutes molecules that are potentially recognizable as biomarkers. We hypothesize that the surface seepage channels emanating from crater walls and cliffs in Mars Orbiter Camera images results from fluvial erosion of the regolith as low-temperature hypersaline brines.

Influence of ice and snow covers on the UV exposure of terrestrial microbial communities: dosimetric studies.

Bacillus subtilis spore biological dosimeters and electronic dosimeters were used to investigate the exposure of terrestrial microbial communities in micro-habitats covered by snow and ice in Antarctica. The melting of snow covers of between 5- and 15-cm thickness, depending on age and heterogeneity, could increase B. subtilis spore inactivation by up to an order of magnitude, a relative increase twice that caused by a 50% ozone depletion.

Exo/Astrobiology in Europe.

The question of the chemical origins of life is engraved in the European scientific patrimony as it can be traced back to the pioneer ideas of Charles Darwin, Louis Pasteur, and more recently to Alexander Oparin. During the last decades, the European community of origin of life scientists has organized seven out of the twelve International Conferences on the Origins of Life held since 1957. This community contributed also to enlarge the field of research to the study of life in extreme environments and to the search for extraterrestrial life, i.

The state and future of Mars polar science and exploration.

As the planet's principal cold traps, the martian polar regions have accumulated extensive mantles of ice and dust that cover individual areas of approximately 10(6) km2 and total as much as 3-4 km thick. From the scarcity of superposed craters on their surface, these layered deposits are thought to be comparatively young--preserving a record of the seasonal and climatic cycling of atmospheric CO2, H2O, and dust over the past approximately 10(5)-10(8) years. For this reason, the martian polar deposits may serve as a Rosetta Stone for understanding the geologic and climatic history of the planet--documenting variations in insolation (due to quasiperiodic oscillations in the planet's obliquity and orbital elements), volatile mass balance, atmospheric composition, dust storm activity, volcanic eruptions, large impacts, catastrophic floods, solar luminosity, supernovae, and perhaps even a record of microbial life.

Investigations into an unknown organism on the martian meteorite Allan Hills 84001.

Examination of fracture surfaces near the fusion crust of the martian meteorite Allan Hills (ALH) 84001 have been conducted using scanning electron microscopy (SEM) and atomic force microscopy (AFM) and has revealed structures strongly resembling mycelium. These structures were compared with similar structures found in Antarctic cryptoendolithic communities. On morphology alone, we conclude that these features are not only terrestrial in origin but probably belong to a member of the Actinomycetales, which we consider was introduced during the Antarctic residency of this meteorite.

Aerobic endospore-forming bacteria from geothermal environments in northern Victoria Land, Antarctica, and Candlemas Island, South Sandwich archipelago, with the proposal of Bacillus fumarioli sp. nov.

Aerobic endospore-forming bacteria were isolated from soils taken from active fumaroles on Mount Rittmann and Mount Melbourne in northern Victoria Land, Antarctica, and from active and inactive fumaroles on Candlemas Island, South Sandwich archipelago. The Mt Rittmann and Mt Melbourne soils yielded a dominant, moderately thermophilic and acidophilic, aerobic endospore-former growing at pH 5.5 and 50 degrees C, and further strains of the same organism were isolated from a cold, dead fumarole at Clinker Gulch, Candlemas Island.

Phosphatase Activities of Endolithic Communities in Rocks of the Antarctic Dry Valleys.

Phosphorus is scarce in Beacon Sandstone of the McMurdo Dry Valleys, Antarctica, and any input from precipitation is minimal. In endolithic microbial communities recycling of P by the action of phosphatases may therefore be important. The phosphatase activities of three different types of endolithic communities in the McMurdo Dry Valley, Antarctica, were studied in the laboratory.

Vibrational raman spectroscopic study of scytonemin, the UV-protective cyanobacterial pigment.

The Raman spectrum of the photoprotective pigment scytonemin found in cyanobacterial sheaths has been obtained for the first time. Its skeletal structure is extensively conjugated and unique in nature. Detailed molecular vibrational assignments are proposed and a distinctive group of four corroborative vibrational bands have been identified as unique indicators for the compound.

Response of pioneer soil microalgal colonists to environmental change in Antarctica.

There is increasing evidence of climate change in Antarctica, especially elevated temperature and ultraviolet B (UVB) flux within the ozone "hole." Its origins are debatable, but the effects on ice recession, water availability, and summer growth conditions are demonstrable. Light-dependent, temperature-sensitive, fast-growing organisms respond to these physical and biogeographical changes.