(ORDO NEWS) — At an altitude of 8 thousand meters above sea level in the Himalayan mountains there is a rocky gorge between Everest and its sister peak Lhotse, blown by winds and free of snow.
It is here, on the South Col, that every year hundreds of adventurers make their last camp before attempting to climb the world‘s highest peak from the southeast.
They also leave behind a frozen legacy of hardy microbes that can survive harsh conditions at high altitudes and lie dormant for decades or even centuries, according to new research from the University of Colorado Boulder.
The study not only highlights the invisible impact of tourism on the world’s tallest mountain, but it could also lead to a better understanding of the ecological limits of life on Earth, as well as where life might exist on other planets or cold moons.
“There is a human signature frozen in the Everest microbiome, even at this altitude,” said senior author of the paper and professor of ecology and evolutionary biology Steve Schmidt.
In past decades, scientists have not been able to definitively identify human-related microbes in samples collected at an eight-kilometer altitude.
The new study marks the first time that next-generation gene sequencing technology has been used to analyze soil from such a high altitude on Mount Everest, allowing researchers to gain new insights into just about everything and everything in them.
The researchers weren’t surprised to find microorganisms left behind by humans. Germs are everywhere, even in the air, and can easily fly and land some distance from nearby camps or trails.
However, they were impressed that some of the microbes that evolved to thrive in warm and humid environments, such as our noses and mouths, were resilient enough to survive dormant in such harsh environments.
The research team took soil samples from everywhere, from Antarctica and the Andes to the Himalayas and the high Arctic.
Typically, human-associated microbes are not found in these areas to the extent that they have appeared in recent Everest samples.
Schmidt’s years of work connected him with researchers who traveled to the South Col of Everest in May 2019 to build the highest weather station on the planet, built by National Geographic and the Rolex Perpetual Planet Everest Expedition. He asked his colleagues to take soil samples there.
The scientists analyzed the soil and, using next-generation gene sequencing technology and more traditional cultivation methods, they were able to identify the DNA of virtually any living or dead microbe in the soil.
They then performed extensive bioinformatic analysis of DNA sequences to determine the diversity of organisms rather than their numbers.
Most of the microbial DNA sequences they found were similar to hardy or “extremophile” organisms previously found in other high altitude locations in the Andes and Antarctica.
The most common organism they found, using both old and new methods, was a fungus of the genus Naganishia, which can withstand extreme levels of cold and ultraviolet radiation.
But they also found microbial DNA from some organisms closely related to humans, including Staphylococcus, one of the most common bacteria in the skin and nose, and Streptococcus, the dominant genus in the human mouth.
At high altitude, microbes are often killed by ultraviolet light, low temperatures, and lack of water. Only the toughest creatures survive.
Most of them, like microbes raised by humans to great heights, hibernate or die, but there is a chance that organisms like Naganishia can grow briefly when water and perfect sunlight provide enough warmth to help them thrive for a moment.
But even to the most resistant germs, Mount Everest is Hotel California: “You can check out anytime you want / But you can never leave.”
Researchers do not expect this microscopic impact on Everest to significantly affect the environment as a whole.
But this work has implications for the potential for life far beyond Earth, if humans one day set foot on Mars or beyond.
“We could find life on other planets and cold moons,” Schmidt said. “We have to be careful to make sure we don’t pollute them with our own.”
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