400 de milioane de ani de fosile păstrate în cache dezvăluie viața timpurie

O mică bucată de plantă fosilă a Rinului cu ciuperci fosile care colonizează membrele, văzută la microscop. Credit: Loron et al.

Tehnologia de ultimă oră a dezvăluit noi perspective asupra unui tezaur de fosile de renume mondial, care poate oferi indicii importante cu privire la viața timpurie pe Pământ.

Oamenii de știință care investighează fosilele vechi de 400 de milioane de ani, descoperite în îndepărtata regiune de nord-est a Scoției, raportează că rezultatele lor arată un nivel mai ridicat de conservare moleculară în aceste fosile decât se aștepta anterior.

O nouă examinare a tezaurului bine conservat din Aberdeenshire a permis oamenilor de știință să identifice amprentele chimice ale diferitelor organisme din el.

Așa cum Piatra Rosetta i-a ajutat pe egiptologi să traducă hieroglife, echipa speră că aceste simboluri alchimice vor ajuta la înțelegerea mai multor despre identitatea formelor de viață, care sunt reprezentate de alte fosile, mai obscure.

Mineralizat și acoperit cu rocă tare compusă din silice, ecosistemul fosil uimitor a fost descoperit în apropierea satului Rhynie din Aberdeenshire în 1912. Cunoscut sub numele de Rhynie chert, provine din perioada Devonian timpurie – acum aproximativ 407 milioane de ani – și are un rol important în înțelegerea de către oamenii de știință a vieții de pe Pământ.

Cercetătorii au combinat cele mai recente în imagistica nedistructivă, analiza datelor și[{” attribute=””>machine learning to analyze fossils from collections held by National Museums Scotland and the Universities of Aberdeen and Oxford. Scientists from the University of Edinburgh were able to probe deeper than has previously been possible, which they say could reveal new insights about less well-preserved samples.

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

Since they already knew which organisms most of the fossils represented, the team was able to discover molecular fingerprints that reliably discriminate 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, which are found in Devonian – and later Silurian – sediments have both algal and fungal characteristics and were previously hard to place in either category. The new findings indicate that they were unlikely to have been either lichens or fungi.

Dr. Sean McMahon, Chancellor’s Fellow from the University of Edinburgh’s School of Physics and Astronomy and School of GeoSciences, said: “We have shown how a quick, non-invasive method can be used to discriminate between different lifeforms, and this opens a unique window on 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, providing the potential for sorting other datasets from other fossil-bearing rocks.

The study, published in Nature Communications, was funded by The Royal Society, Wallonia–Brussels International, and the National Council of Science and Technology of Mexico.

Dr Corentin Loron, Royal Society Newton International Fellow from the University of Edinburgh’s School of Physics and Astronomy said the study shows 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 for studying life in trickier, more ambiguous remnants,” Dr. Loron said.

Dr. Nick Fraser, Keeper of Natural Sciences at National Museums Scotland, believes the value of museum collections for understanding our world should never be underestimated.

He said: “The continued development of analytical techniques provides new avenues to explore the past. Our new study provides one more way of peering ever deeper into the fossil record.”

Reference: “Molecular fingerprints resolve affinities of Rhynie chert organic fossils” by C. C. Loron, E. Rodriguez Dzul, P. J. Orr, A. V. Gromov, N. C. Fraser and S. McMahon, 13 March 2023, Nature Communications.
DOI: 10.1038/s41467-023-37047-1