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The Race for Hydrogen Fuel Has Taken These Scientists to the Arctic Seafloor. But Can They Unlock Its Secrets Before It’s Too Late?
On challenging expeditions, researchers have collected deep-sea bacteria that naturally produce hydrogen, exploring and documenting an ancient ecosystem that may soon be altered forever
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The sun never sets during the Arctic summer; it only flirts with the horizon to create an eerie twilight. From the deck of a research vessel on the seemingly endless expanse of gray, cold ocean, this offers the only natural sense for the passage of days.
Juan Galarza, a molecular ecologist at the University of Oulu in Finland, often lost track of time due to these “disorienting” conditions, as he and his team combed the high Arctic during the summer of 2024. They spent the perpetual daylight obsessively staring at a deep-sea scanner’s monitor and hoping for signs of methane bubbles.
Such a signal could indicate that they had found a cold seep, a deep-sea site from which fluids or gases, like methane, escape through cracks on the seafloor. Through an energy-producing process known as chemosynthesis, microscopic life can sustain itself on these gases, thriving in the total darkness and near-freezing conditions. And some of these bacteria, Galarza believes, could kickstart clean energy innovation.
“These microbes have evolved millions of years there in isolation,” Galarza explains. “This is one of the least explored systems ever.”
Did you know? Cold seeps vs. hydrothermal vents
- Both cold seeps and hydrothermal vents lie in deep-sea ecosystems where sunlight doesn’t reach, and they support chemosynthetic organisms that make energy through chemical reactions.
- Cold seeps, where fluids and gases like methane and hydrogen sulfide emerge from the seafloor, are typically the temperature of the surrounding water. Hydrothermal vents are hot and linked to volcanism—mineral-rich water, heated by magma to more than 750 degrees Fahrenheit, emerges in these zones.
A fellow marine biologist had alerted Galarza about simple bacteria thought to feed off methane at cold seeps in the Arctic and naturally produce hydrogen as a byproduct of their metabolic cycle. This potential inspired him to dream: If only he could find these microbes in the sediment and study how they produce hydrogen, it could lead to new ways of making hydrogen fuel, a potentially clean and renewable energy source that produces only water as a byproduct when burned.
His team has returned to the Arctic seafloor two times since to find and collect bacteria samples, most recently this summer. Galarza says he’s encouraged by their progress toward harnessing the microbes’ hydrogen-producing genes in sustainable fuel development.
But the Arctic Ocean is undergoing rapid alterations due to climate change. As they search the seafloor for new discoveries, scientists are acutely aware that the life there might change—or even disappear—before it is fully understood.
“We’re studying an ecosystem changing very quickly,” says Henry Huntington, the head of Arctic science research at the Ocean Conservancy, who is not involved with Galarza’s team. “It’s very hard to know which direction things will go.”
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The new prospectors
Hydrogen is the most common element in the universe—present in an estimated 90 percent of atoms—but to be used as fuel, it must be harnessed in its pure, unbonded form. Natural hydrogen, as this is known, is rare; to produce it, the element usually needs to be separated from hydrogen-containing molecules, such as water or natural gas.
While hydrogen has the potential to be a clean alternative fuel for combustion engines, the need to isolate the element has prevented it from breaking into mainstream use. Separating hydrogen is an energy-intensive and expensive process, and hydrogen is only a clean energy source if that separation is powered by a renewable grid, rather than by fossil fuels.
But today, demand for alternative energies has resurrected interest in hydrogen fuel, and some industry experts believe it could yet play a crucial role in the energy infrastructure of tomorrow.
“Anywhere that you can use natural gas, you could use hydrogen,” explains Naomi Boness, a geophysicist who previously worked at Chevron but is now the managing director of the Center for Fuels of the Future at Stanford University, which explores methods of decarbonizing key sectors of the global economy.
She sees hydrogen fuel as being particularly useful in heavy industries that would otherwise be difficult to electrify, like aviation or shipping. Cars can go electric, but “it’s really hard to imagine, for example, how you would electrify a long-haul airplane,” Boness says. She estimates that 50 percent of the global economy will still be dependent on combustion engines by 2060. “What are we going to do about all these really fuel-dependent sectors?"
Hydrogen is a potential answer, she says. If breakthroughs make harvesting natural hydrogen more economically and environmentally viable, it could be an “ultimate game changer for humanity,” Boness adds. “It would completely revolutionize how we use energy in our systems.”
Investors and governments are pouring billions into startups and research efforts, hoping to lower the cost and emissions needed to create hydrogen fuel—and by doing so, take hold of a multibillion-dollar industry. Others are betting big on discovering natural hydrogen underground, thereby removing the need to separate it from another molecule.
“It’s like the early days of oil and gas exploration,” Boness says.
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For their part, Galarza’s Arctic team—funded by H2Future, a coalition of European governments and energy investors seeking breakthroughs in hydrogen fuel—is exploring the hydrogen-producing bacteria at cold seeps. They plan to study the organisms’ genetics to learn exactly how they produce the gas in near-freezing conditions.
That genetic coding, Galarza says, could inform new hydrogen-related biotechnologies. For example, he could “copy-paste” hydrogen-making enzymes into other bacteria, such as E. coli, that are commonly cultivated at industrial scales in labs. Unlike the cold seep bacteria, E. coli do not require methane to survive, removing the potent greenhouse gas from the production process.
Other scientists have experimented with using green algae to produce hydrogen. But Galarza says E. coli, spliced with the hydrogen-producing enzymes, offers an advantage over that: The bacteria could be fed industrial waste to grow, helping recycle the refuse from businesses like paper mills. Then, the microbes generate hydrogen, possibly producing higher yields than algae, and could be harvested for fuel and other commercial purposes.
Bubbles in the deep
When Galarza pitched the project to H2 Future, he warned that they might not find a cold seep with the right characteristics to yield bacteria samples. Seafloor data on the Arctic is limited, and cold seeps are mostly undocumented. Galarza tempered his expectations: “It’s better if you are a pessimist, because in that case, you are either right or pleasantly surprised.”
On the initial expedition in 2024, his research team journeyed for weeks across the waters north of Svalbard, a Norwegian archipelago well within the Arctic Circle. Drawing from 20-year-old oceanographic data and the locations of fault lines, where they believed cold seeps might occur, they searched for the promised microbes. But the harsh conditions of the Arctic compounded the challenge.
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The high Arctic remains one of the most difficult and dangerous environments for conducting research. Chartering vessels and crews can cost around $20,000 per day. So Galarza and his team found other scientists—like geologists and oceanographers—to split the cost, packing the vessel with as many people as possible. But this led to a new problem: not enough beds. As such, when they needed to sleep, they surveyed uninhabited islands off the northern tip of Svalbard for polar bears and made camp on land, armed with rifles.
Sea ice would sometimes block their routes. Then storms seemingly conjured from nowhere, forcing them to pause their research and find refuge. At one point, the extreme weather caught them so off guard that they were forced to abandon their belongings—including computers with expedition data—at a campsite while they fled to the safety of Longyearbyen, the capital of Svalbard, and waited for the storm to pass. (Another expedition ultimately retrieved their equipment.)
While at sea, Galarza’s team monitored their deep-sea scanners 24 hours a day, alternating in four-hour shifts—or changing out when seasickness hit and a team member needed to look out a window to gather their senses. They didn’t want to miss any signs of bubbles.
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On the final day of their expedition, they had yet to discover a cold seep with the right conditions for bacteria. Galarza had resigned himself to disappointment when a member of his team spotted bubbles on the scanner. He didn’t celebrate, as they’d had false alarms before when similar bubbles turned out to be a pod of whales passing below or a different chemical, like sulfide.
Their tests eventually revealed it was exactly what they were looking for: a cold seep with the right conditions for hydrogen-producing bacteria to live in the sediment surrounding methane vents. “We were not really believing it until we confirmed, like, three times with different instruments,” Galarza says.
The discovery provided a lifeline for the research and secured the team more funding. They returned to find the microbes living freely there, and they have now carefully collected soil samples from four active cold seeps, using strict biosecurity measures to contain the bacteria. Then, in the safety of their lab, they brought microbes that have lived in seclusion for millions of years under the lens of a microscope.
Simple, vulnerable life
For generations, it was assumed that life required sunlight to exist. It wasn’t until the late 20th century that scientists discovered entire ecosystems feeding off chemicals erupting through the seafloor. These oases of life endured in the abyss of the ocean, thousands of feet beneath the reach of the last strands of sunlight.
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Partly because of these hostile and remote conditions, the bacteria at cold seeps have gone mostly undisturbed for millions of years. In that time, they’ve become uniquely efficient at producing hydrogen.
“They are very specialized organisms that have to adapt to these extreme conditions,” Galarza explains. Evolution has made them more simple over time. “They only kept the essential genes and enzymes to survive there, and anything else is gone.”
Yet the same conditions that have allowed the bacteria to simplify over generations also make them highly vulnerable to any changes in their environment, which has been stable for millennia. “They are not used to variation,” Galarza explains. Any subtle shifts to the biochemistry of the water could force them to adapt to survive—and perhaps lose that “specialist” ability to produce hydrogen.
Today, the Arctic is changing faster than any other region on the planet—and those effects are trickling down to the seafloor.
The loss of sea ice could affect nutrient levels throughout the water column. When spring arrives and sunlight breaks the long Arctic night, life blooms underneath the ice—a garden of algae nourishes creatures at all depths of the ocean.
This is known as the Arctic’s “spring bloom” according to Huntington. Algae blooms with such abundance that some of it goes unconsumed at the top layers of the ocean. “A lot of the stuff just winds up sinking to the seafloor,” Huntington says, “so you get an incredibly rich ocean bottom.”
But if the timing and abundance of this bloom changes with shrinking sea ice coverage, it could impact a sensitive and diverse web of deep-sea life that scientists are only beginning to discover—including microbes, sponges, sea stars and even coral reefs.
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Changes to salinity also pose significant uncertainties. As waters warm, sea ice retreats and glaciers melt, saltier Atlantic currents have crept further north, a process known as the “Atlantification” of the Arctic. These changes mix the various layers of the Arctic Ocean: Saltier water sinks lower and pushes fresher water to the top, altering the spread of nutrients.
“Biologists still don’t know what would be the response of the ecological system to this new physical environment of layers,” explains Igor Polyakov, an Arctic researcher at the University of Alaska Fairbanks.
Galarza has been startled by the rapid biochemical changes that he’s seen in the water, due to shifting salinity levels and shrinking sea ice that alters the intensity and timing of sunlight breaking through the surface. His team has found more than 800 species of undescribed microbes living near the cold seeps, but many of them could perish due to the changing conditions.
“We are documenting environments that might not be there in ten years,” he says. “We are losing a lot of species there, and I’m just looking at the bacteria.”
Galarza’s team has collected genetic samples from the bacteria and is now working on isolating the hydrogen-producing enzymes. Due to the simplicity of their genetics, this has been easier than Galarza expected.
“I have never been so fast in assembling a genome,” he says. Though there are many steps yet to be completed—such as developing new technologies to capture the hydrogen from the bacteria—he is encouraged by the early results.
While Galarza hopes he has what he needs to continue his hydrogen research, he fears that many of the other microbes living on the Arctic seafloor could disappear before they are studied—and with them, potential secrets to vaccines and cancer treatments or breakthroughs in how we search for extraterrestrial life could also vanish.
“What could be discovered from those environments?” Galarza says. “The potential is unquantifiable.”
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