Hydrothermal vents: Earth’s blueprint for finding alien life

Hydrothermal systems are gateways to some of the most fascinating processes shaping our planet.

The Arctic Ocean’s Polaris hydrothermal field is a site that is rewriting what we know about vent diversity and the role of hydrothermal activity in sustaining life on Earth – and possibly beyond.

Recent studies have revealed a broader range of venting styles than experts had anticipated, recalibrating our understanding of these vents’ origins and their larger impact on our oceans and planet.

The Polaris hydrothermal field

Our story unfolds at the Polaris hydrothermal field, located in the Arctic Ocean on the ultraslow-spreading Gakkel Ridge.

Initial studies painted a picture of Polaris as a classic “black smoker” system, caused by its proximity to a volcanic seamount and the temperature and turbidity anomalies in its hydrothermal plume.

But the story of the Polaris field has taken a surprising turn. After comprehensive seafloor surveys and geochemical analyses, scientists discovered that Polaris was not your average black smoker.

Instead, it discharges hydrogen- and methane-enriched fluids into the Arctic Ocean.

Hydrothermal life: More diverse than we knew

What’s more, the deep-sea hydrothermal plumes detected along ultra-slow spreading mid-ocean ridges have revealed a diversity of venting styles beyond what was previously reported.

According to scientists at the Woods Hole Oceanographic Institution (WHOI), this expansion of geodiversity has stretched even into the Arctic Ocean, broadening our understanding of the workings of our planet’s oceans.

“Hydrogen-rich vents like Polaris have a lot more chemical potential energy available for life than any other kinds of vents,” explained Chris German, senior scientist at WHOI.

“The microbial diversity you get when there is that much energy available also is really quite impressive and distinct from most ordinary hydrothermal vents.”

Implications for life beyond Earth

These insights into the workings of our ocean hold not only earthly significance but also carry weight for the possibilities of life beyond our planet.

“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 in a credible and meaningful way, based on what we now know,” said German.

The Arctic ocean: A window into the unknown

The Arctic Ocean, one of the least-explored places on Earth, serves as a window into geological processes that would otherwise remain hidden.

“The insights we gained from the Polaris hydrothermal system were unexpected, with major implications for hydrothermal exploration in other oceans. We are excited to learn what other surprises the Arctic holds in the future,” noted Elmar Albers, a postdoctoral investigator at WHOI.

Connecting life on Earth to outer space

Unraveling the mysteries of our home planet serves as a stepping stone toward understanding the distribution of life in the universe.

“What we learn here, in the Arctic or anywhere on Earth, is directly applied to our successful exploration at other worlds, like Europa and Enceladus, and beyond,” said Becky McCauley Rench, Astrobiology Program Scientist at NASA headquarters.

This study was primarily supported by NASA’s PSTAR program at WHOI and the prestigious Alexander von Humboldt Foundation.

As we continue to explore into the ocean’s mysteries, we are reminded of the intricate connections between our own planet and the vast universe that exists beyond it.

Hydrothermal systems and the origins of life

The Polaris hydrothermal field stands out not only for its diversity but also for its unique chemical signatures.

Unlike traditional black smoker systems that expel iron- and sulfur-rich fluids, Polaris emits hydrogen- and methane-enriched plumes. These gases fuel specialized microbial communities that thrive in the absence of sunlight, using chemical energy to sustain life.

These hydrogen-rich environments are hotspots for chemosynthesis, a process where microbes convert chemical energy into organic matter.

The potential energy available in these systems makes them exceptional laboratories for studying how life could arise and persist under extreme conditions, both on Earth and on other ocean worlds.

This distinctive chemistry has implications for understanding how hydrothermal systems may have contributed to the origin of life.

The chemical gradients observed at Polaris mirror the energy sources theorized to have supported early life on Earth, providing a compelling analog for extraterrestrial environments.

The full study was published in the journal Earth and Planetary Science Letters.

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