Ötzi the Iceman represents an extreme state of biological cessation.
His demise occurred 5,300 years ago, with his remains undergoing exceptional mummification within the glacial confines of Italy’s Ötztal Alps—a discovery ranking among the most ancient and remarkably preserved human mummies ever unearthed.
The frigid alpine milieu where his life concluded effectively inhibited microbial proliferation. As microorganisms are the primary agents of decay, the Iceman was spared from the usual destructive processes.
However, it is plausible that the Iceman’s corporeal form was not entirely devoid of vital activity.
A recent investigation into the microbial communities inhabiting his entire body suggests the presence of potentially active species that may be almost as ancient as the mummy himself, while others might have adapted to the cryogenic conditions of his current repository.
“A mummy’s microbiome presents a unique scenario, as we are examining microbes that are over 5,000 years old, simultaneously coexisting with contemporary microbes introduced subsequent to the discovery,” stated lead author Mohamed Sarhan, a microbiologist affiliated with Eurac Research in Italy.
Ötzi (pronounced similarly to ‘curtsy’ sans the initial ‘c’) was serendipitously found in 1991. Two trekkers initially mistook him for a recently deceased mountaineer, whose form was partially protruding from the melting ice of a glacier, situated at an altitude of 3,210 meters (10,530 feet).
It was only upon the transfer of his remains to a scientific facility that researchers grasped the profound significance of the finding: a hunter from the Copper Age, who lived and perished circa 3300 BCE, preserved so extraordinarily that he appeared to be a much more recent individual.
Subsequent scientific inquiries have yielded substantial insights into Ötzi.
He was approximately 46 years old at the time of his death, bore at least 61 tattoos meticulously applied to his darkened skin, was clad in garments constructed from the hides of various animals, and had consumed a final repast abundant in ibex fat, wild game, and grains.
Prior investigations even delved into his intestinal microbial composition, observing a profile more akin to that of historical, non-industrialized human populations rather than contemporary Western demographics.
Scientists also successfully isolated an ancient variant of *Helicobacter pylori*, the gastric bacterium currently associated with ulcers and stomach cancer.
Nevertheless, a common thread ran through all these studies: the microbes were predominantly regarded as biological remnants, with little to no consideration given to their potential extant activity.
Furthermore, no comprehensive effort had been made to differentiate Ötzi’s indigenous microbiome from exogenous contaminants that might have infiltrated his body post-mortem, both within the glacier and subsequently during his transfer to cold storage to avert decomposition.
Sarhan and his associates collected swab samples from Ötzi’s entire body, in addition to meltwater extracted from within him. They also incorporated data from previous examinations of his intestinal and stomach tissues, and analyzed a soil sample sourced from his discovery site, collected concurrently with the Iceman.
These samples underwent DNA and RNA sequencing to identify microbial patterns.
The microbial communities broadly segregated into two primary categories. The first comprised ancient microorganisms integral to Ötzi’s living microbiome.
The second group consisted of psychrophilic yeasts detected on Ötzi’s skin and within meltwater collected internally. These were highly specialized species adapted to frigid environments, genetically affiliated with microorganisms found in polar regions like Antarctica.
This observation suggests that these microbes likely originated from the glacial environment that facilitated the preservation of Ötzi’s remains.
However, an additional peculiar finding emerged. Certain samples displayed significant degradation, indicative of ancient microbial origins, while others appeared relatively recent, suggesting ongoing metabolic activity.
“We observe a continuity here,” remarked microbiologist Frank Maixner, director of the Institute for Mummy Studies at Eurac Research.
“These yeasts have accompanied Ötzi on his extensive journey through the millennia.”
Another intriguing aspect of this complex scenario warrants mention. Some of the microorganisms may have benefited from the conservation methodologies applied to the body.
Following its discovery, Ötzi’s body was treated with phenol, a toxic compound employed to inhibit fungal growth. Notably, three of the four identified yeast species possess the metabolic capacity to process phenol.
It is important to clarify that definitively distinguishing between descendants of an unbroken lineage of microbes that inhabited Ötzi’s body for millennia, even in extreme cold, and those that were dormant and revived post-thawing remains challenging.
Nevertheless, the available evidence strongly implicates that Ötzi’s body, in some manner, facilitated their continued viability.
Samples collected in 2010 and 2019 indicated an increase in one psychrophilic species over the intervening decade, suggesting that at least some of these microorganisms are surviving and even undergoing slow proliferation under the sub-zero conditions of Ötzi’s preservation chamber.
“The Iceman mummy is not a static artifact but rather a dynamic ecosystem serving as a living archive, where ancient glacier-derived microbes and modern contaminants coexist under museum conditions,” the researchers detailed in their publication.
These discoveries have been disseminated in the journal *Microbiome*.
