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A new model for silicification of cyanobacteria in Proterozoic tidal flats
Author(s) -
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,
Bosak Tanja
Publication year - 2021
Publication title -
geobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.859
H-Index - 72
eISSN - 1472-4669
pISSN - 1472-4677
DOI - 10.1111/gbi.12447
Subject(s) - seawater , proterozoic , cyanobacteria , microbial mat , diagenesis , stromatolite , extracellular polymeric substance , geology , biosphere , acritarch , benthic zone , fossilization , artificial seawater , environmental chemistry , ecology , geochemistry , oceanography , biofilm , carbonate , paleontology , chemistry , bacteria , biology , organic chemistry , tectonics , linguistics , philosophy
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 (Mg 2+ ), and >70 ppm silica.