Assessing siliceous sinter matrices for long-term preservation of lipid biomarkers in opaline sinter deposits analogous to Mars in El Tatio (Chile).

Subaerial hydrothermal systems are of great interest for paleobiology and astrobiology as plausible candidate environments to support the origin of life on Earth that offer a unique and interrelated atmosphere-hydrosphere-lithosphere interface. They harbor extensive sinter deposits of high preservation potential that are promising targets in the search for traces of possible extraterrestrial life on Hesperian Mars. However, long-term quality preservation is paramount for recognizing biosignatures in old samples and there are still significant gaps in our understanding of the impact and extent of taphonomy processes on life fingerprints.

Ultraviolet radiation-induced limitation to epilithic microbial growth in arid deserts--dosimetric experiments in the hyperarid core of the Atacama Desert.

Experiments were conducted during November 2003 in the dry core of the Atacama Desert, Yungay, Chile to test the hypothesis that UV radiation, in environments where liquid water is not available, and thus enzymatic repair of UV-induced damage is inhibited, can prevent epilithic colonization. Novel dosimeters made from the cryptoendolithic, desiccation and radiation-resistant cyanobacterium Chroococcidiopsis sp. isolated from the dry Negev desert, Israel, showed that monolayers of this organism were killed within one day.