Bacterial paleontology from the neontologist point of view

Abstract

Bacterial paleontology is oriented towards recognition of bacterial remnants as microfossils in the sedimentary rock. Presence of bacteria in ancient rocks makes a fundamental contribution to the understanding of the most part of the history of the biosphere as an empirical date set and starting point for its reconstruction corrected for microtaphonomy conditions. In addition to use of organowalled and silicified microbial structures SEM adds fascinating new possibilities, which are however based on neontological dates. It is not realized how poor is the knowledge of neontological microbiologists obtained from direct microscopic observations and how disputable are conclusions made on this basis. Only mass development, as e.g. in microbial mats, is accepted by microbial ecologists as a fact for consideration. The large body of information obtained from molecular methods in situ identification of phylogenetic position is not in the facilities of bacterial paleontology. Morphology in most cases is insufficient for understanding the functioning of bacteria. In paleontological record function might be deduced from the composition of biogenic minerals. Bacterial mineralogy both in formation of minerals and destruction of lithogenic ones makes the critical link between Life and Earth sciences for interpretation of Precambrian events. Etching of minerals indicating microbially mediated weathering might be the major source of information particularly for subaerial environments, which are most poorly understood parts of processes in past. Another point is the link between microbial landscape and facial analysis based on paleontological and geological reconstructions. Relict microbial communities in volcanic and evaporative environments seems to be the key model sites for the reconstruction. Bacterial paleontology now is a well established and proliferating field of basic knowledge, which cannot develop without its own methodology formed with large input from actualistic models.