Every year, hundreds of climbers camp at the South Col on the southern slope of Mount Everest in preparation for their attempt to reach the roof of the world.
While these adventurers can take home some well-deserved bragging rights, a new study shows they can also leave behind tenacious microbes that seem capable of coaxing each other to survive on icy, desolate outcrops.
Despite the extreme conditions on Everest, the researchers were able to grow bacteria and fungi isolated from the mountain’s sediments. These organisms, which are mostly dormant, may have been transported from less extreme terrain to the snowless dip of the South Col by wind or by humans.
This study reveals the impact of tourists on the world’s highest peak and could shed light on the limits of life on Earth and the potential for life on other worlds.
Located in the Mahalangur Himal range of the Himalayas, Mount Everest (Sagarmatha in Nepali, or Chomolungma in Tibetan) stands taller than any other land surface on Earth, towering 29,031 feet (8,849 meters) above sea level.
Everest’s high altitude environments are among the most extreme on Earth. South Col, where the research team led by microbial ecologist Nicholas Dragone of the University of Colorado Boulder (CU Boulder) collected soil samples, sits about 7,900 feet above sea level. the sea.
So researchers were surprised to find that even microbes that have adapted to the warm, moist comfort of our noses and throats, like Staphylococcus And Streptococcuswere able to remain dormant and survive the harsh, cold and dry conditions.
“There is a frozen human signature in Everest’s microbiome, even at this altitude,” said lead author Steven Schmidt, microbial ecologist at CU Boulder.
“If someone even blew their nose or coughed, that’s the kind of thing that could show up.”
In addition to traditional culture techniques involving the growth of bacteria on nutrient-rich agar plates, the team sequenced extracts of genetic material in the soils to identify specific microbes. This would be the highest altitude that such samples have ever been examined in this way.
Team members examined soil samples from places like the Andes as good as Himalayas and Antarctica before, but let’s say this is the first time samples taken at this altitude have shown definitive evidence of human-related microorganisms.
Higher concentrations of ultraviolet light, lower temperatures, and a lack of water all contribute to the death of microbes at high altitudes, so only the hardiest organisms can make it through a climate as hostile as this.
Staphylococcus And Streptococcus bacteria are often found in soil, but the genetic sequences identified in this study were identical to those of common species that usually colonize our skin and mouth.
Additionally, the samples were taken about 170 meters (558 feet) from where snotty, snorting, and sneezing humans typically set up camp before taking on the summit challenge.
“We anticipate that if we take samples from the most human-used areas on the mountain, we might find even more microbial evidence of human impact on the environment,” the team said. write in their paper.
Most microbes, like those carried by humans to high altitudes, go dormant or die when exposed to such extreme conditions, but some organisms can thrive during brief periods of water availability at altitudes high, according to Previous search.
Because air temperatures at South Col rarely rise above −10 °C (14 °F), it is unclear whether or not the scarcity of water from melting ice may promote growth. microbial growth, and it is no mean feat to test microbial growth at such extreme sites.
Thus, the ground of South Col and other places at high altitudes can only collect and freeze organisms that have been deposited there by the air or by people. The better conditions in the lab may be what helped them grow.
However, air temperatures in the Mount Everest region are on the rise at around 0.33°C per decade, and in July 2022 the South Col recorded a record -1.4°C. This warming trend could cause currently inactive organisms to become active in the future.
The authors say that the recently installed South Col weather station could give more information over time and more observations are made.
For now, researchers don’t think this small addition of human germs to Everest will have a big impact on the environment. Nevertheless, this work has implications for the search for extraterrestrial life, for example, in the event that humans eventually reach March.
“We could find life on other planets and cold moons”, said Schmidt.
“We will have to be careful not to contaminate them with ours.”
The study was published in the journal Arctic, Antarctic and Alpine Research.