Pre-study to the deciphering of the cryptic microfossil Frutexites

• Applicant: Professorin Dr. Christine Heim
• Subject Area: Palaeontology
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 406069319

Stromatolitic iron-rich structures have been reported from many ancient environments and are often interpreted as Frutexites, a cryptic microfossil first described by Maslov (1960). Although a microbial formation is likely, a clear relation to a microbial precursor is lacking. My initial microbiological and biogeochemical investigations of recent Frutexites-like biofilms from the Äspö Hard Rock Laboratory in Sweden revealed the presence of a diverse complex community of bacteria, archaea, algae and fungi. Therefore, the major task of this project will be the investigation of several recent biofilms which are quite similar to the fossil Frutexites and to identify characteristic biosignatures. The recent (living) Frutexites-like biofilms will be sampled from six different locations in Sweden and Germany. These Frutexites samples will be microscopically and geochemically investigated and compared among each other. This project is designed as a pre-study. If the results are promising, a larger project is planned, where the biosignatures identified in this study help to determine similarities of recent and fossil Frutexites from different geological time scales and to evaluate their relevance for the ancient iron cycle.The research findings of the proposed project will not only be relevant for those interested in biosignatures, and Frutexites, but are expected to yield interesting information for microbial communities consisting of bacteria and fungi and important implications for studies on life in subsurface environments.

• DFG Programme: Research Grants