The Silicification of Thermophilic Biofilms: Are Geothermal Deposits Analogs for the Preservation of Extraterrestrial Life?

Abstract

Laboratory experiments have been conducted to study the growth of silica sinters in the presence and absence of thermophilic bacteria at 60oC. In all experiments, a ledge of silica sinter grew off the substrate surface following the air-water interface along the meniscus. In abiotic experiments, this was composed of an aggregate of well-formed silica spherules. In biotic experiments, these spherules were poorly formed due to the inference of organic molecules from the bacterial nutrient. Numerous bacterial cells were observed in the biotic experiments. These form part of thermophilic biofilms. Silicification of these biofilms has a strong influence on the silica sinter textures found.