A new study has found that humans are leaving behind a frozen legacy of hardy microbes on Mount Everest, which can withstand harsh conditions and lie dormant in the soil for decades or even centuries. The researchers were not surprised to find microorganisms left by humans but what stumped them was the presence of certain microbes that have evolved to thrive in warm and wet environments like our noses and mouths which have now become resilient enough to survive in a dormant state in such harsh conditions.
Most of the microbial DNA sequences found were similar to hardy, or extremophilic organisms previously detected in other high-elevation sites in the Andes and Antarctica. The most abundant organism they found using both old and new methods was a fungus in the genus Naganishia that can withstand extreme levels of cold and UV radiation. But even pathogens heavily associated with humans, including Staphylococcus, one of the most common skin and nose bacteria, and Streptococcus, a dominant genus in the human mouth, were found.
At high elevation, microbes are often killed by ultraviolet light, cold temperatures and low water availability. Only the hardiest critters survive. There is a chance that organisms like Naganishia may grow briefly when water and the perfect ray of sunlight provides enough heat to help it momentarily prosper.
