Deep-sea ecosystems may never heal from mining damage
07-28-2025

Deep-sea ecosystems may never heal from mining damage

The deep sea holds mysteries we’ve barely begun to understand. It’s vast, dark, cold, and alive with astonishing biodiversity. Beneath its crushing pressures lie mineral-rich fields containing metals that are vital to emerging technologies.

These include cobalt, nickel, copper, and manganese, which are crucial for electric vehicles, renewable energy storage, and advanced electronics.

Targets for deep-sea mining

Now, international companies are eyeing this remote frontier for large-scale mining. Their target is polymetallic nodules, potato-sized lumps that are scattered across the ocean floor, especially in the central Pacific. These nodules formed over millions of years.

Some businesses claim they can harvest the nodules with little environmental damage. Scientists, however, are sounding the alarm.

At a recent meeting of the International Seabed Authority (ISA) in Kingston, Jamaica, researchers presented troubling data. They questioned whether deep-sea ecosystems could ever recover from mining disruption.

This conversation arrives as nations push forward to finalize rules for commercial seabed extraction.

Mining may cause deep sea damage

The DEEP REST project, led by European scientists, has spent years examining seafloor restoration. “If we remove nodules from the seabed, we do not know what we lose, only that it’s lost forever,” the researchers concluded.

Jozee Sarrazin, a researcher at the French Institute for Ocean Science (Ifremer), explained the scope of the problem.

“So far, all the restoration operations we have attempted within our DEEP REST project have been short-term. And what we observed is that, in the given time, that is to say a few years, the ecosystems do not recover,” she said.

The DEEP REST team emphasized that the long-term prospects remain uncertain. “If restoration is possible, it will take a very long time, and at the moment we don’t have the data to be able to say if that will be 100 years or 1000 years,” Sarrazin said.

These findings question the very foundation of the seabed mining industry’s environmental claims. The damage may not just last centuries. It might never heal.

Ocean life depends on nodules

Though hostile in appearance, the deep sea teems with life. Far from being barren, the abyss is likely home to millions of unknown species. Creatures survive without sunlight, relying instead on chemical reactions, organic matter from above, and symbiotic relationships.

Among these residents are sponges, soft corals, sea anemones, and countless microorganisms. They depend on the hard surface of polymetallic nodules to anchor themselves in soft sediment. Without these nodules, many species cannot survive.

Matthias Haeckel, from the German research center GEOMAR, highlighted this critical dependency. “The fauna only exists in these areas because they need the hard substrate of the nodule to attach,” Haeckel said during his presentation of the MiningImpact project in Jamaica.

Mining causes damage to sea life

Mining techniques involve vacuuming up nodules while releasing plumes of sediment. These activities disturb a wide radius around each site.

The MiningImpact study found that this approach decreases population densities and biodiversity while impairing ecosystem function.

The nodules themselves are not replaceable within any human timeframe. “To make the story short, in the end, we’re talking about recovery times of thousands of years,” said Haeckel. These timescales stretch far beyond any meaningful conservation plan.

The process does more than displace marine life. It affects how nutrients cycle, how species interact, and how habitats maintain balance. With no way to predict full outcomes, many researchers urge restraint.

Damage remains despite mining trials

Some scientists are testing whether restoration can be engineered. “We designed artificial nodules made of deep-sea clay and we placed them at different sites,” noted Sabine Gollner, a biologist at the Royal Netherlands Institute for Sea Research.

These nodules mimic the natural substrates that marine organisms need. But results take time.

“When you take into account the slow growth rates in the deep sea, the slow processes, it will take quite some more years to find out if restoration is effective and to what degree,” Gollner noted.

Even with creative ideas and dedicated research, restoration remains hypothetical. No one can yet claim success at bringing back lost deep-sea ecosystems. And until long-term data become available, every mining operation risks doing irreversible damage.

Some areas should remain untouched

One type of deep-sea habitat holds particular value: hydrothermal vents. These underwater geysers release heated, mineral-rich water through cracks in the seafloor. The ecosystems built around them are among the most unique on Earth.

Massive sulfide deposits near these vents are rich in metals, making them tempting targets for mining. But scientists caution that damage here would be catastrophic.

“If we extract massive sulfides near active vents, we know what we lose, and we must prevent loss,” the DEEP REST study concluded.

These sites support specialized creatures found nowhere else. Their removal would erase entire evolutionary pathways. The vents also play a role in regulating global chemistry and microbial activity.

Mining rules ignore long-term damage

The ISA continues negotiating the international mining code. Scientists urge that these rules must include restoration principles, but also acknowledge a hard truth.

“It’s good to include it but with a clear statement that at this moment in time, it cannot be taken into account to reach agreed environmental goals,” said Gollner. “For example, a contractor shouldn’t be allowed to use that argument to mine a larger area.”

Until the world better understands the deep sea, calls for caution continue to grow. The rush for critical minerals may lead us to destroy what we do not yet comprehend.

Mining the seafloor risks losing lifeforms and systems shaped over eons, all for short-term technological gain.

What lies ahead for the deep

The deep ocean holds scientific wonder, ecological value, and untapped biodiversity. Once disrupted, it may never return to its natural state. With mining rules still under negotiation, the time to ask hard questions is now.

Can we afford to treat the seafloor as a resource deposit? Or should we recognize it as a living system, still largely uncharted, and protect it accordingly? The world must decide before the damage becomes permanent.

The full study was published in the journal Nature.

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