Observational and experimental approaches in lipid biomarker research: towards a more holistic interpretation of biosignatures in the geologic record on Earth and beyond

Abstract:

Cell membrane lipids are produced by all forms of life while their degradation products (biomarkers) can be preserved in the rock record for up to billions of years. Classically, the study of the structure, distribution, and stable isotopic composition of biomarkers has provided limited taxonomic and metabolic information of the potential source organisms. However, recent studies have demonstrated that biomarkers also encode information about the physiological responses of microorganisms to their changing physical/chemical environment. I will provide an overview of how biomarker research in modern environments is facilitating a more holistic reconstruction of ancient ecosystems in the geologic record. This will include examples of observational and experimental biomarker approaches to study microbial processes in modern marine and terrestrial extreme environments, in addition to the reconstructions of ecosystems across major transitions in Earth history. I will conclude with some take-away points of how these studies can better inform the search of biosignatures elsewhere in the solar system.