PhD: The afterlife of a microbe: experimental production and alteration of fossil micro-organisms

Summary

This project will deploy cutting-edge experimental and micro-analytical techniques to test hypotheses about ancient bacteria and other micro-organisms in the fossil record.

Project background

Micro-organisms like bacteria are the progenitors of all life on Earth and have driven the evolution of our planet for over three billion years. To understand life’s origin, early evolution, and resilience to major environmental changes in Earth history, we must explore the fossil record of ancient bacteria — which also inform the search for life on Mars. But while the significance of fossil bacteria is widely acknowledged, even the best preserved examples are microscopic, morphologically ambiguous, and therefore difficult to interpret, fuelling major debates about the origins of important groups and their relationships to key events in Earth’s history. Recent advances in high-resolution analytical methods reveal the structure and composition of candidate fossil bacteria in unprecedented detail. To interpret these data correctly, we need to understand how bacterial remains actually decay, mineralize, mature, and metamorphose to produce the observable characteristics of fossils.

Research questions

1. How can experimental approaches to the science of fossil preservation ("taphonomy") be adapted for bacteria?
2. How are the identifiable features of selected bacterial groups modified or lost during decay, mineralization, maturation and metamorphism?
3. How do differences in the cell structure and composition of diverse bacterial groups influence their potential to preserve as recognisable fossils?
4. How do taphonomic factors influence our ability to distinguish between fossil bacteria and non-biological mineral structures, e.g., using morphometrics?