Protocells in the Archaean Rock Record: Implications for the Origin of Life and Detection of Biosignatures

Introduction

Fossilised remains of protocells transitioning towards the first living organisms may be observable in the early rock record, distorting our interpretation of biosignatures. Protocells – cellular structures existing prior to the emergence of life – would have comprised simple membranes and molecular machinery.

Understanding Protocells

The formation of complex protocells is poorly understood. The interpretation of fossilised microorganisms in the early rock record is steeped in controversy. The potential for abiotic microstructures to further complicate this interpretation has long been recognised but has not been systematically tested.

Challenges in Distinguishing Structures

Evidence suggests that prebiotic structures are very difficult to distinguish from microfossils. However, little is known about the chemical and physical characteristics of these ‘biomorphs’ that may enable us to tell the difference.

Project Objectives

This project will use a novel microfluidic approach to expand the experimental scope for the formation of protocells of increasing complexity. Resulting microstructures will undergo silicification and diagenesis, the principal preservation pathway for early Archean microfossils.

Analytical Techniques

State-of-the-art analytical techniques will be used to characterise biomorphs, providing the first rigorous investigation of the feasibility of protocell preservation and how this might express in the geological record.

Data Integration and Model Development

These data, combined with a predictive model and biological controls, will allow for the identification of key observables that will act as biogenicity indicators. Purported microfossils will then be examined and reinterpreted using the novel biosignatures.

Impact of the Project

This project has the capacity to represent a paradigm shift in our fundamental understanding of the origin and evolution of life on Earth and possibly elsewhere in the Solar System. Collectively, this will represent a major advance in our understanding of the geological record, providing the first comprehensive methodology to distinguish between abiotic, prebiotic, and biological microstructures.