Science & Technology

Ice core reveals microbes 15,000 years ago

Ice core reveals microbes 15,000 years ago

Extensive glacier action in the highlands of the Tibetan Plateau.
sauce: Reurinkjan

Known as the world “Third pole”, The Tibetan Plateau has a large amount of earth ice. Over 46,000 glaciers cover a vast part of the landscape of dry hills. Hindu Kush Himalaya (HKH) Mountain range.These mountains and their ice fields are collectively Largest amount of snow and ice outside the Arctic and Antarctica.. Given the ancient inaccessible depth of ice, it is easy to speculate that ice is sterile and lifeless beyond its inert composition. But a new study of Tibetan ice cores reveals the exact opposite. These giant glaciers, in fact, hold a rich chronological record of the life of frozen and unique microorganisms.

Zhi-Ping Zhong is a postdoctoral paleoclimatologist at Ohio State University. Bird Polar Climate Research Center, And the lead author New publication In the journal Microbiota Outlines a study of his team of microbes about 15,000 years ago in Tibetan ice. Their innovation lies in their methodology — it is notoriously difficult to isolate and store ancient microbial DNA enough to degrade individual genomes while simultaneously avoiding sample contamination and degradation. In addition, glacier ice contains very low levels of biomass, which poses an even greater risk of contamination by today’s microorganisms and viruses. Zhong and his team have pioneered a new approach to accomplishing this difficult task with incredible accuracy, allowing them to see the ancient genes directly.

“we, Pollutants On the surface of the glacier ice core, “Zhong explained in an interview with Glacier Hub. “This helps ensure that you have access to” real “microbes and viruses stored on glacier ice, not pollutants. The team’s method was to meticulously scrape the core, disinfect even the innermost ice, and isolate relatively uncontaminated material for analysis. They extended their previous work by first verifying the method with artificial cores contaminated with known bacteria and allowing them to measure the amount of simulated pollutants remaining. Using more specific data on the effectiveness of their approach, they proceeded with the actual core cleaning and processing.

The ice core used in the study was excavated from Guliya Ice Cap by Lonnie Thompson et al. In 2015. Thompson, a renowned paleoclimatologist and professor at Ohio State University since 1991, began building an ice core collection at the Bird Polar Climate Research Center decades ago (along with Ellen Mosley-Thumpson). Zhong says glacier ice not only archives chemical information about past climates and the Earth’s atmosphere, but also archives the entire microbial ecosystem, providing preserved biological records dating back thousands of years. Emphasizes to do.

Bacteria growing in Petri dishes

The culture of Sphingomonas, a genus of bacteria found frozen in ancient ice cores.
sauce: Nathan Reading

In-depth pollution control and reduction methods, both inside and outside the research team’s lab, have revealed specific groups of bacteria commonly found in glacier ice. Janthinobacterium, Polaromonas, and Sphingomonas.. However, a survey of the genetic material of the virus revealed the entire study-specific sequence and 28 new genera. This percentage of 88% of new genera found in glacier ice is much higher than that found in viral analysis of the marine environment (52 percent unique genus) And soil (61 percent unique genus). Such discoveries at an extraordinary level of detail are essential to Zhong’s research goals. He explains that he wants to understand long-term microbial mutation rates by comparing the frozen genome to the current bacterial and viral genomes. “These efforts will offer us the possibility of using a kind of molecular clock to help dating ice.”

Potential applications inside. The et al method also does not end on this planet. Life of extremophiles The Earth (including tough ice-dwelling bacteria and other microbes) is frequently studied as a potential model of extraterrestrial life on other planets and satellites.Many bodies of our solar system Harbor water ice, Although in more extreme climatic conditions, Astrobiology assumptions That such ice may be sufficient to provide livable conditions for life. The team’s protocol was developed for the extraction of microorganisms and viruses from the highlands, cold, and dry environments of the Earth, so Zhong said, “In the search for life in the polar regions of Mars and other ice. Someday a similar approach may be applied. ” The world of our solar system. ”

While these technologies hold great hopes for broadening our understanding of the history and evolution of microorganisms, they pose a threat to the existence of climate change with the advent of this area.A quarter of the third pole Melted since 1970, And according to 2019 IPCC Report, Two-thirds of the glacier is projected to disappear within the next 80 years. These catastrophic trends are global to varying degrees, and with snowmelt, the global loss of biological history dating back hundreds of thousands of years occurs as these records move to snowmelt water.

Glacial Research Facility Archive Shelf

Bird Polar and Climate Research Center shelves.
sauce: James St. John

Recognizing this threat, the Bird Polar Climate Research Center has collected and preserved over 7,000 meters of ice core sections through 40 years of glacier ice analysis around the world. NS Bird center freezer Is a time capsule that preserves the history of the world, which may not be readily accessible elsewhere. Both archived ice cores and Zhong’s methods have the potential to serve as the basis for the next generation of researchers. Once the only view of a magnificent and biological glacier, each 4 inches wide and about a yard long. Scientists have barely begun to read the vast genetic books contained in Earth’s glaciers. These new methods of recovering frozen genomes and preserving threatened ice are now facing a battle against fruitful and fateful times.


Ice core reveals microbes 15,000 years ago

https://news.climate.columbia.edu/2021/09/01/glacial-ice-cores-reveal-15000-year-old-microbes/ Ice core reveals microbes 15,000 years ago

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