A groundbreaking study led by researchers at Curtin University has uncovered significant insights into ancient ecosystems by analyzing fossilised faeces, known as ‘coprolites’. This research, published in the journal Geobiology, focuses on coprolites that are approximately 300 million years old, primarily sourced from the Mazon Creek fossil site in the United States. The findings shed light on the dietary habits of prehistoric animals, the environments in which they thrived, and the processes that followed their demise.
The research team discovered that while previous studies indicated the presence of cholesterol derivatives in these coprolites—indicative of a meat-based diet—the new investigation delved deeper into how these fragile molecular traces were preserved over millions of years. Traditionally, soft tissues are thought to be fossilised through phosphate minerals. However, this study revealed that tiny grains of iron carbonate acted as microscopic time capsules, safeguarding these molecular remnants.
Dr. Madison Tripp, an Adjunct Research Fellow at Curtin’s School of Earth and Planetary Sciences and the study’s lead author, remarked on the significance of their findings. “Fossils don’t just preserve the shapes of long-extinct creatures; they can also hold chemical traces of life,” Dr. Tripp explained. “Understanding how these delicate molecules survive is crucial. We found that while phosphate aids in preserving the shape and structure of fossils, it is the iron carbonate that protects the molecular traces inside.”
Expanding the Research Scope
To ascertain whether this mineral-molecule association was exclusive to the Mazon Creek site, the researchers broadened their analysis to include a diverse range of fossils from various species, environments, and time periods. This wider examination confirmed that the preservation mechanisms identified were consistent across the samples.
Professor Kliti Grice, the Founding Director of Curtin’s WA-Organic and Isotope Geochemistry Centre and an ARC Laureate Fellow, stated that these findings indicate a broader pattern in the preservation of biological information. “This isn’t just a one-off or a lucky find; it’s a pattern we are starting to see repeated,” Professor Grice noted. “Carbonate minerals have quietly preserved biological information throughout Earth’s history.”
The implications of this research extend beyond mere academic interest. Understanding which minerals are most effective at preserving ancient biomolecules enables scientists to target specific conditions for fossil searches. “Instead of relying on chance, we can look for specific conditions that offer the best opportunity to uncover molecular clues about ancient life,” Professor Grice added.
Reconstructing Ancient Worlds
The ability to reveal how biomolecules are preserved equips scientists with powerful tools to reconstruct ecosystems that existed hundreds of millions of years ago. “This helps us build a much richer picture of past ecosystems—not just what animals looked like, but how they lived, interacted, and decomposed,” Professor Grice stated. “It brings prehistoric worlds to life in molecular detail.”
The study, titled “Mineralization controls informative biomarker preservation associated with soft part fossilization in deep time,” underscores the potential for future research to provide even deeper insights into the complexities of ancient life.
This research was supported by the Australian Research Council (ARC) Laureate Fellowship program and various grants, highlighting the collaborative effort behind this significant discovery. The findings not only enhance our understanding of prehistoric life but also pave the way for future investigations into the molecular preservation of ancient biological materials.
