Scientists revive microbes dormant in permafrost for 46,000 years
Researchers have successfully awakened ancient microbes trapped in Siberian permafrost for up to 46,000 years. The experiment demonstrates the remarkable resilience of these microorganisms. The findings, published in Nature Communications, raise concerns about potential pathogen release as permafrost thaws due to climate change.
In a groundbreaking study, scientists extracted and revived microbes from permafrost samples collected in the Kolyma River region of northeastern Siberia. The permafrost, a permanently frozen layer of soil, has preserved these microorganisms in a dormant state for millennia. Led by researchers from the University of Minnesota and international collaborators, the team thawed the samples under controlled laboratory conditions and successfully cultured the ancient bacteria.
The microbes, including species from genera such as Arthrobacter, Pseudomonas, and Micrococcus, showed signs of viability after being dormant for between 23,000 and 46,000 years, as determined by radiocarbon dating of the surrounding organic material. 'These microorganisms are incredibly resilient, surviving extreme cold and isolation for tens of thousands of years,' said study co-author Corien Bakermans, a microbiologist at the University of Minnesota. The revival process involved gradually warming the samples and providing nutrients, allowing the bacteria to resume metabolic activity.
This research builds on previous discoveries of ancient life forms in permafrost, but it is notable for the extended dormancy period confirmed here. The samples were collected during expeditions in 2017 and 2018, with genetic analysis revealing that the microbes' DNA remained largely intact despite the harsh conditions. No modern contaminants were detected, ensuring the purity of the revived organisms.
The implications of this work extend to climate science. As global temperatures rise, permafrost in the Arctic is thawing at an accelerating rate, potentially releasing long-dormant pathogens into the environment. 'This study underscores the risk of ancient microbes emerging in a warming world,' Bakermans noted. While the revived bacteria in this experiment were non-pathogenic, the presence of viable cells after such prolonged dormancy highlights the need for further monitoring of permafrost ecosystems.
The findings were detailed in a paper published on October 24, 2023, in Nature Communications, emphasizing the evolutionary adaptations that enable microbial survival in extreme environments. This event marks a key advancement in understanding microbial longevity and its intersection with ongoing environmental changes.