Deep Sea Mining Causes Significant Damage to Seabed Life, Scientists Find
Machines used to mine minerals in the deep ocean cause extensive harm to life on the seabed, according to the largest scientific study of its kind. Researchers found that animal populations were dramatically reduced in areas disturbed by mining vehicles, raising serious concerns about the environmental impact of deep sea mining.
37% Drop in Seabed Animals After Mining Tests
Scientists discovered that the number of animals living in vehicle tracks on the seafloor fell by 37% compared with untouched areas. Species diversity also declined by 32%, highlighting the scale of disruption caused by test mining operations.
“The machine removes about the top five centimetres of sediment. That’s where most of the animals live. So obviously, if you’re removing the sediment, you’re removing the animals in it too,” lead author Eva Stewart, PhD student at the Natural History Museum and the University of Southampton, said.
“Even if they are not killed by the machine, pollution from the mining operations could slowly kill some less resilient species,” said Dr Guadalupe Bribiesca-Contreras from the National Oceanography Centre.
The study focused on small seabed animals between 0.3mm and 2cm in size, including worms, sea spiders, snails and clams. While a small number may have moved away, researchers warned that it remains unclear whether these species can return after such disturbance.
More than 4,000 animals were identified during the research, with around 90% believed to be new species previously unknown to science. The findings underline how little is understood about deep ocean ecosystems and how vulnerable they may be to industrial activity.
The research took place in the Clarion-Clipperton Zone, a remote 6 million square kilometre region of the Pacific Ocean. This area is estimated to contain over 21 billion tonnes of polymetallic nodules rich in nickel, cobalt and copper — minerals considered critical for green technologies.
Demand for Critical Minerals Driving Mining Interest
Critical minerals are essential for renewable energy technologies such as solar panels, wind turbines and electric vehicles. The International Energy Agency predicts that global demand for the minerals could at least double by 2040, increasing pressure to find new sources.
However, scientists and environmental groups warn that mining the deep sea could cause irreversible damage before its ecosystems are fully explored or understood.
The study was carried out by scientists from the Natural History Museum in London, the UK National Oceanography Centre and the University of Gothenburg. It was commissioned by deep sea mining firm The Metals Company.
Researchers stressed that the work was fully independent. Although the company was allowed to view the results before publication, it had no influence over the findings or conclusions.
Interestingly, areas surrounding the vehicle tracks — where clouds of sediment settled — did not show a reduction in the number of animals.
“We were expecting possibly a bit more impact, but [we didn’t] see much, just a shift in which species were dominant over others,” Dr Adrian Glover, research scientist at the Natural History Museum, said.
“We’re encouraged by these data,” a spokesperson for The Metals Company said.
“After years of activist alarm that our impacts would spread thousands of kilometres beyond the mine site, the data show that any biodiversity impacts are limited to the directly mined area,” they added.
However, some experts argue this does not reduce the overall environmental risk and should not be seen as reassurance for mining companies.
“I think the study shows that current technologies for harvesting are too damaging to permit large-scale commercial exploration,” Dr Patrick Schröder, senior research fellow at the Environment and Society Centre at think tank Chatham House, said.
“These were only tests and the impact was significant. If they did that at large scale, it would be even more damaging,” he added.
Deep Sea Mining Remains Highly Controversial
Deep sea mining is not currently permitted in international waters. The International Seabed Authority (ISA) has issued 31 exploration licences but has yet to approve commercial mining. A total of 37 countries, including the UK and France, support a temporary ban.
Norway recently postponed mining plans in its waters, including the Arctic. In contrast, US President Donald Trump has called for domestic and international mining projects to be fast-tracked to secure mineral supplies for defence and industry.
If the ISA determines that current mining techniques are too damaging, companies may be forced to develop less invasive methods for extracting seabed minerals. Scientists caution that oceans already play a critical role in regulating the planet and are under increasing stress from climate change.
The full study has been published in the journal Nature Ecology and Evolution.
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