A recent study led by researchers at the University of Lausanne (UNIL) has brought to light significant findings regarding fossil preservation. Our new analysis published in Nature Communications brings some good news. It underlines just how important an animal’s size and chemical make-up are in deciding its odds of fossilisation over such eons of time. The art serves to illuminate the many gaps in the fossil record. It does so while offering priceless glimpses into the chemical processes at work affecting what parts of ancient life we are able to reconstruct in the present.
Farid Saleh, a Swiss National Science Foundation Ambizione Fellow at UNIL, who acted as senior author of the study. Out of these, principal author Nora Corthésy — who is currently pursuing her Ph.D. at UNIL — made the largest contribution towards this groundbreaking research. They were determined to investigate all of the different things that could possibly promote or inhibit fossilization. This work resulted in an increased understanding of taxon–specific preservation pathways, all ultimately controlled by redox conditions.
The Role of Size and Chemical Makeup
The research emphasizes that the size and chemical composition are key factors in fossilization. They are necessary and sometimes even sufficient conditions for an organism to be able to be preserved. This is in part because larger animals tend to have more material that can be fossilized. Furthermore, some chemical compositions—such as that found in anoxic environments—allow for the preservation of soft tissues, such as muscles, guts, and even brains.
The researchers lawmates that these attributes produce different chances for fossilization among different species. As a result, many of these smaller organisms or those with inherently less ideal chemical profiles are likely underrepresented in the fossil record. This phenomenon plays a critical role in the gaps and inconsistencies paleontologists frequently experience when trying to reconstruct ancient ecosystems.
Chemical Processes and Fossil Preservation
This study delves into the individual chemical mechanisms that affect fossil preservation. Saleh and Corthésy argue that pathways of fossilization are not homogenous but differ greatly between taxa. This variability is primarily controlled by redox conditions, which describe the oxidation-reduction potential of an environment.
Changing conditions, such as exposure to oxygen or water, can radically change the chemical structure of organic materials, making them less likely to be preserved. Sedimentary conditions and water chemistry Sedimentary conditions are the most important factor. They do have a major impact on how well organic tissues survive over geological timescales. These results highlight the importance of understanding these chemical processes to better reconstruct the appearance and biology of past life forms.
Implications for Paleontology
The ramifications of this research go well beyond scientific interest. The study attempts to pinpoint the primary factors that determine fossil preservation. This provides paleontologists with an increasingly powerful and consistent framework through which to interpret the fossil record. This conceptual framework and scientific approach can further illuminate for scientists why some species are easy to find yet others still seem to be elusive.
Yet researchers admit that, because of unavoidable limitations in studying ancient ecosystems, their findings are still somewhat hypothetical. It’s not possible to go back in time and see the precise circumstances that resulted in fossilization. This study does create new possibilities for future research on how different natural conditions affect fossilization.
The researchers provided a notable example from their study: Cretaceous fossil shrimp discovered in Jbel Oum Tkout, Morocco. Currently registered at the Museum d’Histoire Naturelle de Marrakech, these specimens offer concrete proof. Both bolster the claims that size matters and chemical environment plays a role in fossilization.