A new model for silicification of cyanobacteria in Proterozoic tidal flats

Moore, Kelsey R.; Gong, Jian; Pajusalu, Mihkel; Skoog, Emilie J.; Xu, Megan; Feliz Soto, Tania; Sojo, Victor; Matreux, Thomas; Baldes, Matthew J.; Braun, Dieter; Williford, Kenneth and Bosak, Tanja (2021): A new model for silicification of cyanobacteria in Proterozoic tidal flats. In: Geobiology, Vol. 19, No. 5: pp. 438-449

Abstract

Microbial fossils preserved by early diagenetic chert provide a window into the Proterozoic biosphere, but seawater chemistry, microbial processes, and the interactions between microbes and the environment that contributed to this preservation are not well constrained. Here, we use fossilization experiments to explore the processes that preserve marine cyanobacterial biofilms by the precipitation of amorphous silica in a seawater medium that is analogous to Proterozoic seawater. These experiments demonstrate that the exceptional silicification of benthic marine cyanobacteria analogous to the oldest diagnostic cyanobacterial fossils requires interactions among extracellular polymeric substances (EPS), photosynthetically induced pH changes, magnesium cations (Mg2+), and >70 ppm silica.

• Item Type: Journal article
• Faculties: Physics
• Subjects: 500 Science > 530 Physics
• ISSN: 1472-4677
• Language: English