The findings, detailed in the journal article "Ultramafic-influenced submarine venting on basaltic seafloor at the Polaris site, 87N, Gakkel Ridge," published in Earth and Planetary Science Letters, have broad implications for understanding the Earth's hydrothermal systems and their relevance to life beyond our planet.

The study revisited the Polaris hydrothermal field on the Gakkel Ridge in the Arctic Ocean during expeditions in 2016 and 2023. Initially classified as a volcanically-hosted "black smoker" system due to plume anomalies and its seamount location, the site proved to be an unconventional vent system. Researchers discovered that it discharges hydrogen- and methane-rich fluids into the ocean, differing markedly from traditional metal-rich black smoker systems.

While over 30 hydrothermal plume sites have been detected along ultra-slow spreading mid-ocean ridges, detailed analyses of such systems remain sparse. "A diversity of styles of venting has been found, beyond what had previously been reported," the study noted, citing examples like the Aurora hydrothermal field and now the Polaris site.

"Hydrogen-rich vents like Polaris have a lot more chemical potential energy available for life than any other kinds of vents," said Chris German, senior scientist at the Woods Hole Oceanographic Institution and co-author of the study. "The microbial diversity you get when there is that much energy available is really quite impressive and distinct from most ordinary hydrothermal vents."

German, also a principal investigator for NASA's Exploring Ocean Worlds project, emphasized the significance of the findings for astrobiology. "The discoveries we have made here are particularly important because they reassure us that we could go and search for life on other ocean worlds beyond Earth in a credible and meaningful way," he explained.

Lead author Elmar Albers, a postdoctoral investigator at WHOI, highlighted the unexpected nature of the findings. "The insights we gained from the Polaris hydrothermal system were unexpected, with major implications for hydrothermal exploration in other oceans," Albers said, attributing his work to support from the Alexander von Humboldt Foundation.

NASA's Astrobiology Program Scientist Becky McCauley Rench noted the study's broader implications for space exploration. "Understanding the distribution of life in the universe starts here at home in exploring the places and ways that life thrives on Earth," Rench said. She emphasized how the team's work directly informs the search for extraterrestrial life on moons such as Europa and Enceladus.

Research Report:Ultramafic-influenced submarine venting on basaltic seafloor at the Polaris site, 87N, Gakkel Ridge

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