TThe world is on the brink of a new “gold rush.” Except this time, countries are rushing to control the minerals required for solar panels, wind turbines, and batteries. And instead of continuing to dig tunnels or pits, some scientists are looking to a promising — but challenging — source of minerals that has tormented researchers for decades: seawater.
The ocean holds far more than just water and salt. Pretty much every naturally occurring element on the periodic table can be found in seawater, from gold and silver to lithium, cobalt, and nickel.
The problem? For most of history, these metals have been out of reach, because they exist at levels so low that it’s kind of hard to even wrap your head around.
Imagine an olympic-sized swimming pool full of seawater. If you were to separate all the elements, you’d be left with about half a kilogram of lithium, 1.2 grams of nickel, 3 milligrams of cobalt, and similarly small amounts of other sought-after metals. While that might not seem like a lot, the world’s oceans contain about 534 trillion olympic-sized pools’ worth of water. So, while there might not be much, say, cobalt in that hypothetical pool of seawater, there’s a lot of cobalt in the actual seas. In fact, the ocean contains 46 times more cobalt than all of the world’s land reserves combined.
“When you multiply it by this vast volume of seawater on planet Earth — that’s a huge gold mine,” said Scott Edmundson, a research scientist at Pacific Northwest National Lab. “There’s a gold mine, literally right at our shoreline.”
For nearly a century, scientists have been trying to tap into the ocean’s mineral stores — perhaps none more infamous than the German chemist Fritz Haber. Haber started his career as an idealistic young scientist, determined to use chemistry to save the world from famine. At the turn of the 20th century, he invented a method to pull the key ingredient for fertilizer out of thin air — a technique that allowed farmers to grow enough food to save an estimated 3.5 billion lives from starvation. But when World War I broke out, Haber’s story took a dark turn. He retooled his fertilizer factories to make chemical weapons for the Germans instead.
German chemist Fritz Haber developed an innovative technique to pull the key ingredient for fertilizer out of thin air. Later, he infamously turned his attentions toward developing chemical weapons for Germany during World War I. After the war, Haber (third from left) experimented with pulling gold from seawater. Archives of the Max Planck Society, Berlin
After Germany lost the war, the country was in shambles, riddled with war debt. And Haber — now shunned by the scientific community — decided to turn his efforts toward saving his country’s economy. Haber knew that the oceans were filled with gold. And he hatched a plan to extract it. “The legend is that he had this chemistry lab on a transatlantic ocean liner going back and forth and doing seawater chemistry experiments,” Edmundson said. “And it worked — technically.”
Haber’s invention was able to put gold out of seawater. The problem was that it was super inefficient: It turned out that gold was 1,000 times less abundant than he’d expected. Meaning the gold he extracted wasn’t valuable even enough to cover the costs of operating his machinery.
While Haber’s seawater mining plan failed spectacularly, for many scientists, the dream of extracting minerals from the ocean lived on. For example, over the following decades, researchers in countries like the United States, United Kingdom, and Japan all looked into ways to harvest uranium from seawater. But none of those efforts led to widespread success.
And yet today, there’s a renewed interest in seawater, not for gold or uranium, but for the minerals needed for today’s energy transition. A team of scientists at the Pacific Northwest National Lab in Sequim, Washington, have a new plan to extract minerals from the sea, this time, using a billion-year-old living technology: seaweed.
Seaweed is a type of algae — a huge class of photosynthetic organisms that primarily grow in the water. They range from microscopic phytoplankton all the way to giant kelp, which can grow a whopping 2 feet per day. And they all grow by absorbing light from the sun and sucking nutrients and minerals and dissolved CO2 directly out of the ocean.
Scientists at the Pacific Northwest National Lab had already been studying algae for decades as a potential way to make renewable biofuel. They’d grow different kinds of algae in the lab, and then they’d refine it, extracting out all the organic matter for fuel. Without that organic matter, they were left with a powder made of all the stuff that the algae had pulled out of the seawater — including minerals. Initially, that powder was seen as a waste product. But as demand for renewable energy started to take off, the lab realized that its “waste product” was full of the same minerals required for this renewable boom.
“That’s where we started looking at, ‘oh, there’s a lot of minerals here that we really are undervaluing,’” Edmundson said.
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Scott Edmundson and his colleagues at the lab dove in, trying to figure out if they really could get usable minerals from this algae waste product. The first step was finding the right type of algae. They scoured Washington’s coasts, searching for the species that concentrated the most critical minerals. This led them to a fast-growing native seaweed called ulva.
“Ulva is one of my favorite seaweeds,” Edmundson said. “It’s definitely a rockstar of the seaweed world.”
Researchers at the lab built a system to pump seawater into their onshore lab. This allowed them to fine tune the temperature, lighting, and currents to create the perfect conditions for ulva to suck up minerals. The seaweed is so good at filtering out minerals that mineral levels can be up to a million of times higher than the original seawater.
“The seaweeds have this remarkable capacity to bring it up orders of magnitude,” Edmundson said. “So you’re getting into the realm of, now we can do something with it.”
Once the seaweed has been harvested and dried, researchers use a machine that heats and pressurizes it, turning all the organic matter into a liquid that they can use for things like biofuels. This process leaves behind that mineral-rich powder, which they call bio-ore.
On a recent visit to the lab, Edmundson showed me a small container of bio-ore, which resembled a colorless powder. “All the organics in the seaweed have been removed, and we’re just left with the minerals,” Edmundson said, holding the jar. He then picked up another jar filled with a clay-red colored powder. “Each seaweed has this different mineral composition,” he said. “This one you can see is much, much redder. So this one has much higher iron content.”
At this point, the bio-ore is concentrated enough for a mining processor to turn it into pure minerals for batteries or solar panels.
Beyond seaweed, scientists are looking at other ways to extract minerals from the ocean. Maha Haji, an assistant professor at Cornell’s Sibley School of Mechanical and Aerospace Engineering, is working on a plan to hang big mineral filters off of decommissioned oil rigs. A few years ago, she looked into what would happen if all the retiring oil rigs in the Gulf of Mexico were instead converted into seawater mineral extractors.
“With a little bit more research and development on the materials side, you could maybe extract over a quarter of the cobalt demand in the United States,” Haji said. “That’s a sizable amount of cobalt.”
While large-scale seawater mining is still a ways off, both scientists feel this technology has the potential to completely reshape mining as we know it. For most of history, precious minerals have been clustered in a handful of resource-rich hotspots. In those hotspots, people would do whatever it took to control those resources: They’d fight wars, destroy surrounding ecosystems, or violate human rights.
Seawater mining could change that. For starters, 77 percent of countries have access to a coastline. “It opens up a whole new world where pretty much any country with a coastline could harvest minerals for their own use,” Haji said. “It almost democratizes mining and mineral harvesting.”
For Edmundson, he sees seaweed as a way to turn mining into an environmentally positive activity, since the seaweed can filter out pollutants and combat ocean acidification.
“If you can make that work, and you can do it in a way that’s environmentally responsible, that has such high potential for providing the minerals we need in a sustainable kind of egalitarian way,” Edmundson said. “If you have access to the ocean, you have access to the minerals.”
Read the full mining issue
A guide to the 4 minerals shaping the world’s energy future
Chile’s lithium boom promises jobs and money — but threatens a
critical water source
Most critical minerals are on Indigenous lands. Will miners respect
tribal sovereignty?
The energy transition could turn Greenland into a mining mecca. Would
it be for better or for worse?
Digging for minerals in the Pacific’s graveyard: the $20 trillion
fight over who controls the seabed
Mining is an environmental and human rights nightmare. Battery
recycling can ease that.
Tradeoffs of the green transition: Is mining critical minerals better
than extracting fossil fuels?
Why Biden and Trump both support this federal mineral mapping projecty
The weirdest ways scientists are mining for critical minerals, from
water to weeds
In the race to find critical minerals, there’s a ‘gold mine’ literally
at our shoreline
This story was originally published by Grist with the headline In the race to find critical minerals, there’s a ‘gold mine’ literally at our shoreline on Mar 26, 2025.
Instead of continuing to dig tunnels or pits, some scientists are looking to a promising — but challenging — source of minerals: seawater. Energy, Grist Original Videos, Science, Solutions, Video Grist
