Scottish fossil hotspot reveals new secrets about early life forms

Brand new scanning technology penetrates world-famous fossil remains and gives us a glimpse into the world of microbes as they existed more than 400 million years ago.

The molecular footprint of bacteria, fungi and other mysterious creatures has never been more clearly under the magnifying glass. And for good reason: it can tell us more about the origin, evolution and interaction of early life on our planet. A team from the Scottish University of Edinburgh is very enthusiastic about their new FTIR spectroscopy, a technique that uses infrared light to penetrate deep into fossil remains without damaging them. In addition, much more and more accurate data can be collected and analyzed than ever before.

Mysterious microbial remains
The scientists focused their scanners on approximately 400 million-year-old fossils from the Rhynie Chert, a surface stratum of hornstone in Aberdeenshire, Scotland, formed in the Early Devonian. At this time there were no trees on earth and animal life was still in its infancy. The Rhynie Chert is an important site for fossils of mainly terrestrial plants. The fossils have taught us a lot about the early evolution of plants, but if we zoom in further on the fossil-rich rocks, they also appear to be full of mysterious remains of microbes.

The team compares the unusual fossil hotspot to the Rosetta Stone, which helped Egyptologists decipher hieroglyphic writing. Similarly, they hope to discover the identity and evolutionary process of ancient life forms by analyzing the chemical codes in Scottish fossils. They apply their latest deep scanning methods to fossil samples from, among others, the collection of the National Museum of Scotland and the University of Oxford. The FTIR data is then fed to a machine learning program, which ultimately yields new insights.

It was already known from previous analyzes which organisms were hidden in the fossils. With this information, it was possible to identify the molecular footprint of the fungi, bacteria and other life forms and thus better tell them apart. The team then used these patterns to further investigate the more mysterious members of the Rhynie ecosystem, including a tube-shaped creature called a ‘nematophyte’. Nematophytes are very special organisms, which we find in fossils from about 430 to 380 million years old. It is unclear where they stand on the evolutionary ladder. They resemble algae but also have fungal properties. The new study shows that they probably do not belong to the lichens or fungi, but deserve a place of their own.

“We show how a fast, non-invasive scanning method can show the difference between the life forms present in fossils. This kind of research has a lot of potential and gives us a great new look at the diversity of early life on Earth,” says researcher Sean McMahon of the University of Edinburgh. The study describes how the team was able to classify the different organisms by processing the data with a machine learning algorithm. In the same way, datasets from other fossils inside rocks can be analyzed.

Physics, chemistry and paleontology join forces
“The study shows how important it is to combine paleontology, physics and chemistry. This gives us new insights into how life on Earth was organized hundreds of millions of years ago,” explains researcher Corentin Loron. Science has once again found a new way to look deeper into the fossil world than ever before and to make new discoveries about times long past, even in less beautiful fossil remains.