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Accueil > Publications > Recherche par années > Années 2000 > 2002

Toporski, JKW ; Steele, A ; Westall, F ; Thomas-Keprta, KL ; McKay, DS

Winner of the 2001 Gerald A. Soffen Memorial Award - The simulated silicification of bacteria - New clues to the modes and timing of bacterial preservation and implications for the search for extraterrestrial microfossils

Astrobiology 2 (1) 1-26

par Administrateur - publié le

Abstract :

Evidence of microbial, life on Earth has been found in siliceous rock formations throughout the geological and fossil record. To understand the mechanisms of silicification and thus improve our search patterns for evidence of fossil microbial life in rocks, a series of controlled laboratory experiments were designed to simulate the silicification of microorganisms. The bacterial strains Pseudomonas fluorescens and Desulphovibrio indonensis were exposed to silicifying media. The experiments were designed to determine how exposure time to silicifying solutions and to silicifying solutions of different Si concentration affect the fossilization of microbial biofilms. The silicified biofilms were analyzed using transmission electron microscopy (TEM) in combination with energy-dispersive spectroscopy. Both bacterial species showed evidence of silicification after 24 h in 1,000 ppm silica solution, although D. indonensis was less prone to silicification.