Curtin University researchers have found sterols, including cholesterol, coexisting with their fossilised counterparts (geomolecules) in a 380-million-year-old crab-like fossil from the Western Kimberley – a discovery previously assumed unfeasible.
The research, recently published in Nature Scientific Reports, demonstrates sterols can be preserved for longer through an exceptional preservation process, providing the oldest and most extensive molecular relics of the Devonian age.
PhD student Ines Melendez of the WA Organic and Isotope Geochemistry Centre (WA-OIGC) at Curtin led the study alongside her primary advisor, Professor Kliti Grice, Director of WA-OIGC, and visiting Professor Lorenz Schwark from Christian Albrechts University, Kiel, Germany.
“The exceptional preservation of the crab-like fossil, which has extended the occurrence of sterols by 250 million years, is a consequence of early microbial encapsulation preventing full decomposition in the Devonian seas,” Ms Melendez said.
Ms Melendez said the coexistence of more than 70 steroids in one sample confirmed a proposed scheme for the transformation of biomolecules into geomolecules (the fossilised version), reported in Science and Nature in 1982.
“However, we now know this was a microbially induced process rather than thermally driven one as previously assumed,” Ms Melendez said.
Professor Grice said their research demonstrates concretions within rocks were able to preserve biomolecules and geomolecules at remarkable levels.
“This opens up a novel window of opportunity to study such components in very ancient samples and improves our understanding of microbial evolution and past environmental conditions,” Professor Grice said.
This research has been funded by the Australian Research Council under a second QEII Discovery project grant awarded to Professor Grice. Professor Grice has also recently been awarded a Discovery Outstanding Research Award to continue this research. .
A copy of the paper is available at http://www.nature.com/srep/index.html
Ines Melendez, PhD student, Department of Chemistry, Curtin University
Mobile:0416 490 043. Email: Ines.Melendez@curtin.edu.au;
Professor Kliti Grice, Department of Chemistry, Curtin University
Megan Meates, Public Relations, Curtin University
Tel: 08 9266 4241; Mobile: 0401 103 755; Email: firstname.lastname@example.org