President Donald Trump is laser-focused on securing high-value critical minerals for the United States, whether through pushing to buy Greenland or demanding a share of Ukraine’s resources. But there’s another — and possibly far more dangerous — place where he now seeks them: the ocean depths.

Thousands of feet underwater lie potentially lucrative treasure troves of copper, cobalt, nickel, zinc, manganese and other minerals that are vital for computer chips, modern batteries and other products needed for the clean energy transition.

There is currently no commercial deep-sea mining happening anywhere in the world, though companies have been pushing for years. They appear to have found a new champion in Trump. In April, he signed an executive order to kickstart a commercial deep-sea mining industry.

It’s hugely controversial.

The deep ocean is one of the planet’s last wild frontiers and its least-known environment — more than 99% of remains a mystery to humans. Scientists warn mining here could cause irreparable damage to species and ecosystems that have evolved over millions of years and host a rich tapestry of life.

Deep-sea mining targets three very different types of ecosystems.

Most interest is in polymetallic modules: small, potato-sized rocks scattered across parts of the deep ocean floor. These form over millions of years around a piece of matter, such as a shark’s tooth or shell fragment, and contain metals including copper, nickel, cobalt and traces of rare earths.

Hydrothermal vents are another focus. These are like chimneys pushing out superheated, mineral-rich water from deep beneath the Earth, which solidifies into deposits rich in metals such as copper, zinc and sometimes gold and silver.

Then there are seamounts, underwater mountains that rise thousands of feet above the seabed and have cobalt-rich crusts.

These minerals are found in oceans across the planet, but the focus of many mining companies is on an expanse of Pacific Ocean between Mexico and Hawaii called the Clarion-Clipperton Zone, which spans more than 3,000 miles and is around 12,000 to 18,000 feet deep.

The International Seabed Authority, a UN-backed regulator, has issued 30 exploration licenses to companies, the majority of those in the Clarion-Clipperton Zone.

Companies are still developing mining vehicles, but one method would be to use large tractor-sized machines that drive across the sea floor plucking up nodules and transporting them via long pipes to a ship on the surface. Here they would be washed and separated, with sediment pumped back into the ocean.

Hydrothermal vents and seamounts are likely to be more tricky to mine. Plans include using remotely-operated vehicles to scrape up and pulverize mineral deposits before sending the mixture up to the surface.

Whichever techniques are used, mining thousands of feet underwater, where temperatures are very low and the pressure is extreme, is likely to be immensely challenging.

The inky ocean depths are often assumed to be barren, but this is a myth, said Adrian Glover, a deep-sea ocean scientist at the UK’s Natural History Museum. They are “actually surprisingly rich in biodiversity,” he told CNN.

Hydrothermal vents, one of the most extreme habitats on Earth, teem with life. There are yeti crabs, nicknamed Hoff crabs for a resemblance to the hairy-chested actor David Hasselhoff; scaly-foot snails covered in iron armor; and colonies of giant tube worms that can grow more than 6 feet long.

Nodules provide a habitat to species including sponges, soft corals and sea anemones and the muddy abyssal plains are home to sea cucumbers, starfish, anemones, crustaceans, worms and sponges.

Scientists still have a lot to learn. Around 90% of species in the Clarion-Clipperton Zone alone are unknown to science, according to a 2023 study.

There are huge uncertainties given how little is known about the ocean depths, but scientists say impacts could be vast, including an irreversible loss of biodiversity.

Research suggests sediment plumes kicked up by mining could harm marine life, as could the mud pumped back into the ocean from support ships.

Light and noise are other concerns. One study found sounds from a deep-sea mine could reverberate through the ocean for more than 300 miles, disturbing whales, dolphins and other creatures.

Longer term, there are fears that damage to deep-sea landscapes could have ripple effects through the ocean and potentially affect fisheries.

Mining could even affect the “dark oxygen” scientists recently discovered is produced by nodules, which they say could help them unravel the origins of life.

It’s unclear how fast mined areas would recover.

A group of scientists recently studied a strip of seabed southeast of Hawaii where a small scale experiment to mine nodules took place 44 years ago. There were still deep tread marks in the ocean floor, left by the machines. “It looks like the tracks could have been made yesterday,” said Glover, who was part of the project.

The area showed clear long-term changes from mining, although there were “some of the first signs of biological recovery,” the researchers said.

Deep-sea mining companies say many concerns are overblown and contradict their commissioned science. “The notion that we don’t know enough about this environment is blatantly wrong,” said Gerard Barron, the CEO of The Metals Company, a high-profile Canadian deep-sea mining company.

“We’re not saying there’s zero impact. We’re just saying the impact is a fraction compared to the known set of impacts that are happening today on land,” he told CNN.

Land-based mining is beset with environmental and human rights problems, including child labor and rainforest destruction.

Some research, however, suggests ocean mining will not stop or reduce land-based mining, but rather open a new frontier.

“Starting a whole new extractive industry that scientists have already said will cause irreversible biodiversity loss is not a good idea,” said Louisa Casson, global project leader for Greenpeace’s campaign to stop deep-sea mining.

While the appetite for many critical minerals is soaring, some experts say demand can be brought down by recycling, reusing and reducing consumption.

Technology is also changing with efforts to develop batteries that eliminate the need for cobalt and nickel.

Companies including BMW and Samsung have even backed calls for a pause on deep-sea mining.

Some have questioned the economic case for the industry given the challenges of operating machinery in such extreme environments and the swings of mineral markets. “Deep-sea mining is a high-risk, low-reward gamble with no credible economic case,” Democratic Oregon Rep. Maxine Dexter posted on X this week.

A spokesperson for The Metals Company said ocean mining technology was developed and tested in the 1970s “by industrial titans” and has been “honed for lightest impact.” The economics “beat most land-based mines,” the spokesperson told CNN.

This is the million-dollar question.

Any country can mine its own water. Norway voted last year to open part of its Arctic seabed to deep-sea mining but has since paused the project.

As negotiations rumble on, mining companies have grown impatient. Trump’s executive order offers a way to bypass the international process and start extracting.

A US deep-sea mining industry is essential to counter China’s aggressive pursuit of ocean minerals, a White House spokesperson said, and domestic laws would ensure strong environmental protection standards. The National Oceanic and Atmospheric Administration, which will be responsible for issuing licenses, told CNN there would be “a multi-step process before any exploration activities or commercial recovery can occur.”

How long that process will take may soon become clear. The Metals Company submitted an application to NOAA at the end of April to mine in the Clarion-Clipperton Zone.

The International Seabed Authority sharply criticized Trump’s order. Any unilateral action to mine international water “sets a dangerous precedent that could destabilize the entire system of global ocean governance,” said Leticia Reis de Carvalho, the ISA’s secretary general.

Environmental groups have also been heavily critical.

“Authorizing deep-sea mining outside international law is like lighting a match in a room full of dynamite — it threatens ecosystems, global cooperation, and US credibility,” said Arlo Hemphill, project lead on Greenpeace USA’s campaign to stop deep-sea mining.

The year is shaping up to be crucial for determining the future of deep-sea mining. If and when companies will be able to get machines on the seafloor is far from clear. “Every government that has tried to start deep-sea mining has failed,” said Greenpeace’s Casson.

“In the end, it’s a political decision as to whether the risk is worth taking,” Glover said.