An experiment carried out in “corpse farms” made it possible to verify that the decomposition of human bodies and other species always attracts the same varieties of microorganisms and fungi, regardless of the climate, the season of the year or the location on the globe. Better knowledge of this “universal” community of decomposers will allow important advances in forensic investigations in the future.
A team of researchers led by Jessica Metcalf, a professor at Colorado State University in the United States, describes in a new study published in Nature Microbiology that there is a network of approximately 20 microbes that universally drive the decomposition of animal flesh. The findings have significant implications for the future of forensic science, including the potential to provide a more accurate way to determine the time of death of a body.
A fundamental process
The microbial decomposition of organic matter is one of the most important processes on Earth, but the controls that influence it are not well known. In the new research, specialists analyzed 36 human corpses located in three different forensic anthropological facilities, demonstrating that a microbial network with similar characteristics is assembled during decomposition, despite the effects that location, climate and season may have. of the year.
This universal network of microbial decomposers is characterized by cross-feeding to metabolize the products they can obtain from organic remains. Main bacterial decomposers and fungal They are rare in non-decomposing environments: this indicates that they would be unique to the decomposition of meat, including humans, pigs, mice and cattle. It is likely that insects such as flies and beetles are the fundamental vectors for the dispersal of these microorganisms.
It is worth noting that the bodies used in the research were decomposed in different climates and during the four seasons of the year. The scientific team then collected skin and soil samples during the first 21 days of each decomposing body. With this information, they were able to build a general image of the microbial community or microbiome present at each site. “Essentially, we’re finding out what microbes exist, how they get to the decomposition site, how the landscape changes over time, and what they do in the process,” Metcalf said in a statement. Press release.
An integrated network
The key point is that regardless of climate or soil type, the researchers found the same set of about 20 specialized decomposition microbes in all 36 bodies. What’s more, those microbes arrived at exact times during the 21-day observation period, and the insects They played a key role in its emergence.
“We verified that microbes similar arrive at the same times during decomposition, regardless of any amount of exterior variables that may influence,” added the scientist. In conclusion, scientists believe that the observed synchronism of microbial interactions can be the basis of a solid forensic tool, which will allow the time elapsed since death to be accurately predicted.
Reference
A conserved interdomain microbial network underpins cadaver decomposition despite environmental variables. Jessica Metcalf, Zachary M. Burcham et al. Nature Microbiology (2024). DOI:https://doi.org/10.1038/s41564-023-01580-y