Fossil site is ‘Rosetta Stone’ for understanding early life

Leading technology has uncovered secrets about a world-famous fossil treasure that could provide vital clues about early life on Earth.

Researchers who analyzed the 400-million-year-old cache found in rural northeastern Scotland say their findings show better preservation of the fossils at the molecular level than previously expected.

New examination of the beautifully preserved Aberdeenshire treasure house has allowed scientists to identify the chemical fingerprints of the various organisms within it.

Just as the Rosetta Stone helped Egyptologists translate hieroglyphs, the team hopes these chemical codes can help them decipher more about the identity of the life forms, which other more ambiguous fossils represent.

The spectacular fossil ecosystem near the village of Rhynie in Aberdeenshire was discovered in 1912, mineralized and surrounded by chert – hard rock composed of silica. Known as the Rhynie chert, it dates back to the early Devonian – about 407 million years ago – and plays an important role in scientists’ understanding of life on Earth.

Researchers combined the latest non-destructive imaging with data analytics and machine learning to analyze fossils from collections from National Museums Scotland and the Universities of Aberdeen and Oxford. Scientists at the University of Edinburgh were able to probe deeper than previously possible, which they say could provide new insights into less well-preserved samples.

Using a technique known as FTIR spectroscopy, which uses infrared light to collect high-resolution data, researchers found an impressive preservation of molecular information in the cells, tissues and organisms within the rock.

Because they already knew which organisms represented the most fossils, the team was able to discover molecular fingerprints that reliably distinguish between fungi, bacteria and other groups.

These fingerprints were then used to identify some of the more mysterious members of the Rhynie ecosystem, including two specimens of an enigmatic tubular ‘nematophyte’.

These strange organisms, found in Devonian and later Silurian sediments, have characteristics of both algae and fungi and were previously difficult to place in either category. The new findings indicate that it was unlikely they were lichens or fungi.

Dr. Sean McMahon, Chancellor’s Fellow of the University of Edinburgh’s School of Physics and Astronomy and School of GeoSciences, said: “We have shown how a fast, non-invasive method can be used to distinguish between different life forms, and this opens a unique window into the diversity of early life on Earth.”

The team fed their data into a machine learning algorithm that was able to classify the different organisms, opening up the possibility of sorting through other datasets from other fossiliferous rocks.

Dr. Corentin Loron, Royal Society Newton International Fellow from the University of Edinburgh’s School of Physics and Astronomy, said the study demonstrates the value of bridging paleontology with physics and chemistry to create new insights into early life.

“Our work highlights the unique scientific importance of some of Scotland’s spectacular natural heritage and provides us with a tool to study life in trickier, more ambiguous remains,” said Dr. Loron.

Dr. Nick Fraser, Keeper of Natural Sciences at National Museums Scotland, believes that the value of museum collections in understanding our world should never be underestimated. He said: “The continued development of analytical techniques offers new avenues to explore the past. Our new study provides another way to look ever deeper into the fossil record.”

The research has been published in Nature communication.