See What Deep-Sea Mining Actually Looks Like, 2 Miles Down

Tests like these have taken on greater importance this year as the United States is doing what no other nation has done. The Trump administration is widely expected to soon issue the world’s first commercial permits to mine in international waters, those areas of the ocean that no country can claim.

But seabed mining is not only technologically complex, it is also expensive. And environmentalists say far more research is needed before launching industrial activity at the bottom of the sea.

The United States is moving ahead despite opposition from other countries, which have spent decades trying but failing to agree on global standards for mining in international waters. The American plan to fast-track mining, launched by Mr. Trump last year, could prompt other nations to abandon the international status quo, experts say, to avoid falling behind in the race to the ocean floor.

At the heart of all this is the Clarion-Clipperton Zone, a 1.7-million-square-mile Pacific expanse where the ocean floor is covered with valuable, fist-sized nodules full of critical minerals, as well as enigmatic ocean life.

The expedition there was run by The Metals Company, a Canadian firm at the forefront of the competition to mine the seabed. It had sent the Hidden Gem on one of the world’s first modern deep-sea-mining efforts, putting complex technology to the test.

The Trump administration’s plan to issue mining permits in international waters is controversial. Most nations are cooperating on matters concerning international waters through a decades-old United Nations convention called the Law of the Sea. But the United States hasn’t ratified that treaty and says it has the right, under U.S. law, to issue mining permits outside of territorial waters.

The United States has received more than a dozen applications from companies hoping to mine or explore the ocean for minerals. The National Oceanic and Atmospheric Administration recently deemed The Metals Company’s application fit for consideration, paving the way for approval within a year.

The nodules sought by the industry take millions of years to form. They were once fragments of animal bone, shark teeth, shells and rock debris that had settled to the seabed and, over time, accumulated a dense mineral coating made of metallic particles suspended in the water. Billions of tons of these mineral-rich nodules are believed to exist.

Mining them will be difficult and costly, but the argument for doing so is simple. The world needs more metal. Demand for nickel, cobalt and manganese could rise as nations invest in clean energy technologies, like batteries and other emerging industries.

“No mining is sustainable. It is inherently extracting a finite resource,” said Michael Clarke, the environmental manager for The Metals Company. But by nearly every measure, he said, mining the ocean is more ethical compared with the pollution and human rights abuses associated with mining on land.

Critics dispute these claims and say the environmental damage of deep-sea mining could last decades or more. Deep ocean seabeds are one of the least studied and understood areas of the planet and scientists estimate less than 0.001 percent of this part of the world has been seen.

Scientific studies, including some funded by The Metals Company and other mining groups, have shown that life on the floor of the Clarion-Clipperton Zone is beautiful, diverse and slow to recover.

Each scoop of deep ocean sediment can reveal organisms, many of them miniscule, not previously known to science.

“A long time ago, people thought that nothing could possibly ever survive in the deep sea,” said Eva Stewart, a deep sea biologist at the Natural History Museum in London who joined a research expedition funded by The Metals Company. Scientists like Dr. Stewart suspect thousands of animals are waiting to be discovered. “We just haven’t seen them yet,” she said.

Those we have seen are otherworldly. A kaleidoscope of corals, sponges, worms and other animals live on the nodules themselves.

In the surrounding abyss, scientists have found mollusks, snails, worms, sea cucumbers, isopods, starfish and more.

One study, independently published by Dr. Stewart and her colleagues in the journal Nature Ecology and Evolution, found mining would reduce both the abundance and diversity of some deep-sea animals by more than 30 percent. Preliminary results from other researchers show that mining would shift where some animals live.

Proponents of deep-sea mining say the ocean is huge and that the effects found during the 2022 test were isolated. Environmentalists point out that commercial mining would happen at a much bigger scale. The Hidden Gem recovered about 3,000 tons of nodules. If the industry pans out, the company says there’s the potential for collecting millions of tons a year.

The potential pollution from mining, particularly the two sediment plumes, has become a flashpoint of speculation and concern.

Critics once feared that the first plume — the one that forms behind the collector as it moves along the seafloor — could create billowing mud clouds that travel long distances, smothering life along the way. Several studies, including those during the 2022 Hidden Gem expedition, found that most of the plume would settle within the mining tracks, though some particles could travel for several miles. The effect was smaller than experts expected, but would likely still disturb some ocean life.

Scientists who studied the second plume, the one created from sediment pumped up to the ship, found that the mud particles could starve tiny zooplankton, potentially creating a chain of consequences throughout the marine food web. The Metals Company disputes that claim, saying the plume would disperse too quickly to pose a problem.

The company said it plans to avoid this risk during a commercial operation by releasing the plume thousands of feet farther down than it did during the test, to avoid most animal life. But researchers say the plume’s effects haven’t been studied at those depths.

Even if U.S. regulators grant licenses this year, commercial mining is likely still years in the future. A fleet of mining ships doesn’t yet exist, and few refineries are proven capable of turning the nodules into something usable. Environmental groups are expected to challenge any U.S. license in court, while future U.S. administrations could reverse support for the industry.

Despite all of these challenges, the deep-sea mining industry presses on, determined to build a technology that has been the stuff of science fiction for generations.

In 1870, Jules Verne wrote “20,000 Leagues Under the Sea,” the story of Captain Nemo sailing an electric submarine through the lost city of Atlantis on the power of batteries made of elements extracted from the sea.

“The sea is everything,” Captain Nemo said, describing it as an enormous reserve of resources ripe for the taking, but also “a spacious wilderness where man is never alone, for he can feel life throbbing all around him.”