Microbes in fossilization processes

The problem how a corpse becomes a fossil is still unresolved. Nearly all conditions, either oxic or anoxic, lead to fast decay of animal tissue. However, perfectly preserved fossils, buried in sediments, are indicative for rapid suppression of microbial growth. Forensic scientists know a phenomenon conserving drowned corpses for many years – the formation of adipocere (“grave wax“) after saponification of body fat. The resulting calcium and magnesium stearates are difficult to degrade by further microbial attack and may induce formation of fossilizing minerals. We are interested in microbial acivity initiating these processes.

Figure. Tiny mineral precipitates on surfaces of bacterial cells (upper left image) may end up as large calcium carbonate concretions with inside preserved fossils.

References                                                                                                                                                                                                                                Dreier et al., 2014 Geobiology 12: 406-423.                                                                                                                                                                                Dreier et al., 2012 FEMS Microbiol Ecol. 81: 480-493.