Washington.-In the towering heights of the Himalayas, where air is as scarce as transportation options, a group of scientists embark on a mission that could change our understanding of Earth’s past.
On the backs of yaks, the only creatures capable of withstanding the inhospitable terrain, they carry a frozen treasure: segments of an ice core extracted from the Guliya glacier on the Tibetan plateau. What this ancient ice contains is beyond imagination: 1,705 species of viruses, preserved for 41,000 years, whose existence we had never known until now.
This remarkable find, published in the journal Nature Geoscience on August 26, has revealed an unprecedented amount of viral information. The viruses, trapped in ice for millennia, offer a unique window into Earth’s ecological and climatic past.
According to paleoclimatologist and glaciologist Lonnie Thompson, who led the expedition, these microorganisms have been preserved in the glacier like a time capsule, giving us the opportunity to study life forms that have remained unchanged for tens of thousands of years. This discovery is not only a breakthrough in paleovirology, but also provides crucial clues to understanding how microbial communities have responded to climate change throughout the planet’s history.
According to paleoclimatologist and glaciologist Lonnie Thompson, who led the expedition, these microorganisms have been preserved in the glacier like a time capsule, giving us the opportunity to study life forms that have remained unchanged for tens of thousands of years.
This discovery is crucial because it opens an unprecedented window into the Earth’s climatic and ecological past. The viruses found, preserved in their original state for millennia, act as silent witnesses to times when the planet faced environmental conditions very different from those of today.
The study of these ancient viruses provides valuable data on how microbial communities, and viruses in particular, interacted with their environment during different climatic periods.
Matthew Sullivan, co-lead author of the study and a microbiologist at Ohio State University, stressed the importance of these data for raising new questions about Earth’s evolution. With this information, scientists can begin to reconstruct the hidden ecological histories in other glaciers around the world, which could have crucial implications for our understanding of climate change and its effects on microbial biodiversity.
The viruses discovered in Guliya Glacier are much more than mere curiosities of the past; they played a crucial role in the ancient ecosystems where they flourished. These microbes, which primarily infect bacteria and archaea, are critical to understanding how microbial communities have evolved and influenced their environment. Through processes such as selection pressure and virus-mediated gene transfer, these microorganisms dictated the diversity and evolution of species in their respective habitats.
According to Matthew Sullivan, one of the authors of the study, viruses have the ability to shape the ecological metabolism of an ecosystem, that is, they influence which compounds are absorbed from the environment and which are produced as byproducts, as well as at what speed these processes occur. This impact goes beyond simply causing disease; viruses can alter the structure and functioning of ecosystems, acting as agents of change that affect the entire food web from its base.
According to the researchers, some of the viruses found in these “glacial archives” could have played key ecological roles before being frozen in time, offering a unique insight into the ecological dynamics of the past.
The scientists recovered viral DNA from nine different sections of the core, each corresponding to a different climatic period, allowing a detailed study of how environmental conditions have shaped viral diversity over the course of thousands of years.
One of the most significant findings of the study is that the viral community changed markedly in response to climate variations. Matthew Sullivan explains that during cold periods in the past, viruses in the glacier tended to show a similar, though not identical, composition. However, during warm periods, such as the one that occurred about 11,500 years ago during the transition from the Last Glacial Stage to the Holocene, the viral community was much more diverse and distinct from the others. This finding underlines how climate not only influences visible ecosystems, but also the microorganisms that form the base of the food chain.
Lonnie Thompson, co-author of the study, added that the variability in viral composition observed in these samples is a direct reflection of the magnitude of climate changes during those periods. This link between climate and viruses demonstrates the transformative power of the environment on microscopic life and highlights the importance of understanding how these small but powerful agents have historically responded to climate fluctuations, information that could be vital to predicting the responses of current ecosystems to climate change.
Glaciers, with their unique ability to store and preserve genetic data and biotic material, have become crucial repositories of Earth’s climatic and ecological history. Each layer of ice trapped in a glacier like Guliya acts as a natural archive, preserving dust particles, air bubbles, pollen and, as recently revealed, a rich diversity of viruses and other microorganisms. These frozen deposits hold information about the environmental conditions and life forms that existed at the time they formed, giving scientists invaluable insight into the distant past.
However, the rapid melting of glaciers worldwide due to climate change threatens to destroy these natural data banks before we can fully explore them. As the ice melts, we are not only losing fresh water, but also a treasure trove of genetic information that could have significant implications for our understanding of the evolution of life on Earth and its adaptation to extreme conditions.
Aware of this urgency, Lonnie Thompson and his team have embarked on a race against time to collect and analyse as many ice cores as possible before they disappear. The loss of this viral diversity, warns Matthew Sullivan, could deprive us of crucial knowledge about how viruses and other microorganisms have historically responded to climate change – information that could be essential to predicting the future of ecosystems in an increasingly warm world.
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2024-08-30 04:44:14
