The nature of bacteriomorphs: biogenicity and its detection N. 1

As the most abundant organisms on Earth since Early Archean, microbes display a wide range of degradation/fossilization possibilities. The discovery of microorganisms living in extreme terrestrial environments makes now plausible the search for life in the ancient deposits of the early Earth with two issues: i) the understanding of the origin of life on Earth, ii) the search for life on Mars and other planetary bodies which experienced environmental settings similar to the ones of early Earth. A crucial aspect in this investigation, however, is the development of criteria for i) a distinction between biogenic and abiogenic structures, and ii) how to distinguish possible contamination products. The planned experiments focus on the recognition of the actual origin of bacteriomorphs and other alleged microbial morphologies. The target is to assess analytical procedures useful for a proper interpretation of alleged biogenic morphologies for which still ambiguous interpretations and the persisting problem of the sample preparation techniques may prevent their use as actual document of biogenic activity.