Yellowstone-Style Hot Springs May Have Sparked Life on Earth

The question of where life on Earth began has long puzzled scientists, but new research suggests that ancient hot springs, similar to the ones in Yellowstone National Park, may have played a crucial role in the emergence of life. Hot springs, which are heated by volcanic activity beneath the Earth's surface, are rich in minerals, including iron sulfides. These minerals have been linked to early chemical reactions that could have sparked the formation of life. Many scientists have focused on deep-sea hydrothermal vents—which are commonly associated with iron sulfides—as the potential birthplace of life, but a study published in Nature Communications shows that similar reactions may have occurred in land-based hot springs, opening up new possibilities about where life began.

"The inspiration to explore land-based hot springs as potential cradles for the origin of life stems from the unique set of conditions they offer, which differ significantly from deep-sea hydrothermal vents," Jingbo Nan, a co-author of the study, told Newsweek. "Terrestrial environments are more accessible to sunlight radiation, which could drive certain photochemical reactions important in early biochemistry," Nan added. For decades, scientists have believed that deep-sea vents—towering structures on the ocean floor that constantly release a mix of chemicals—were key to the origin of life. These vents are rich in iron sulfides, compounds that play a role in carbon fixation, a fundamental process by which organisms convert carbon dioxide into organic molecules. These same minerals are found in hot springs, which may have provided the same conditions necessary for these life-sustaining reactions. Iron sulfides form when iron reacts with hydrogen sulfide, a gas commonly found in volcanic areas such as Yellowstone. These compounds are essential to the process of carbon fixation, which is critical for all life forms, including bacteria and plants. In fact, many proteins that help with carbon fixation contain iron-sulfur clusters, structures that resemble the iron sulfides found in hot springs and deep-sea vents. Researchers believe these clusters date back to the Last Universal Common Ancestor, an ancient cell from which all life evolved. The team simulated the conditions of ancient hot springs using a custom-built chamber and found that iron sulfides were capable of producing methanol, a key byproduct of carbon fixation. The production of methanol increased when exposed to visible light and higher temperatures, conditions that would have been present in early Earth's hot springs. "One major challenge was keeping the experimental materials pure to simulate early Earth conditions accurately," Shunqin Luo, another of the study's authors, told Newsweek. "The commercially available iron sulfide we first used was contaminated with organic compounds, which disrupted our results," Luo said. The team remedied this by synthesizing their own iron sulfides to ensure they were free of contamination. The study's authors believe that their findings demonstrate the potential for iron sulfides to facilitate the process of carbon fixation in a variety of environments, both on land and at the ocean's depths. The implications don't end on our planet either. Luo added that the findings "also expand the range of environments to consider in the search for extraterrestrial life, particularly on terrestrial planets or moons with surface hydrothermal activity." The study also suggests that the same chemical processes seen in hot springs could have been similar to those occurring within the first cells on Earth. The process of carbon fixation in the laboratory mirrored a pathway used by certain microorganisms to convert carbon dioxide into organic material. This pathway, known as the acetyl-CoA pathway, is believed to have been one of the earliest methods of carbon fixation, providing a possible link between the geochemistry of ancient hot springs and the biology of the first living organisms. This new research expands the range of conditions under which carbon fixation could have occurred on early Earth, showing that it was not limited to the deep sea. The findings suggest that iron-sulfur chemistry could have facilitated the transition from nonliving to living matter in both land-based hot springs and undersea vents, supporting the theory that life could have originated in either environment. While the exact location of life's origin remains uncertain, the study offers new insights into how the first living organisms may have formed. "Whatever the case, our study contributes to the repertoire of potential prebiotic carbon fixation mechanisms in terrestrial hot spring environments," the authors wrote in the study. They added: "This conclusion is consistent with the emerging perspective that such settings, with their unique geochemical conditions and energy sources like sunlight, could have played a significant prebiotic chemical role during life's emergence." Do you have a tip on a science story that Newsweek should be covering? Do you have a question about the origins of life? Let us know via science@newsweek.com.

Reference

Nan, J., Luo, S., Tran, Q. P., Fahrenbach, A. C., Lu, W.-N., Hu, Y., Yin, Z., Ye, J., & Van Kranendonk, M. J. (2024). Iron sulfide-catalyzed gaseous CO2 reduction and prebiotic carbon fixation in terrestrial hot springs. Nature Communications, 15(1), 10280. https://doi.org/10.1038/s41467-024-54062-y Update 12/3/24, 5:12 a.m. ET: The article was updated with comments from Shunqin Luo and Jingbo Nan.