Deep-sea mining found to significantly reduce life on the seabed

MORE than a third of seafloor animals were found to have been wiped out by deep-sea mining activity, according to a damning study conducted in one of the most sought-after areas of the Pacific Ocean.

Interest in deep-sea mining has surged in recent years due to rising demand for critical minerals. Regions such as the Pacific Ocean are known to be particularly mineral-rich and already host projects led by 17 deep-sea mining contractors.

Led by researchers from the UK’s Natural History Museum, the National Oceanography Centre and the University of Gothenburg, the study was commissioned by the deep-sea mining firm conducting the trial, The Metals Company.

Marine impact

Over a two-year period, a prototype polymetallic nodule mining vehicle was dispatched into the Clarion–Clipperton Zone in the Pacific Ocean, where it tracked 80 km of abyssal seafloor and collected 3,000 t of mineral-rich nodules using first-of-its-kind mining equipment. The nodules in the Pacific Ocean contain rare earth elements and other valuable metals, including cobalt, manganese and nickel – all of which are in high demand for battery production.

The study examined the impact of the trial on marine life and found that the number of small animals – including worms, sea spiders and snails – in the test area had fallen by 37% compared with regions outside the trial zone.

Eva Stewart, a PhD student at the Natural History Museum and the University of Southampton, said: “The machine removes about the top 5 cm 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.”

However, the study found that there was no significant reduction of animal life in the immediate areas surrounding the vehicle tracks.

Deep impact

Deep-sea mining is highly controversial due to its potential impacts on marine ecosystems, particularly in international waters.

Commercial mining in these areas is not yet permitted, as negotiations within the International Seabed Authority (ISA) are still ongoing and no agreement has been reached on a regulatory framework.

Despite the lack of regulation and formal approval, some deep-sea mining companies, including The Metals Company, are seeking to bypass the ISA by applying for licences through the US, which operates under a separate mining code.

Other countries are moving to ban the practice altogether because of its impact on marine life. Portugal, for example, has prohibited deep-sea mining in its national waters.

Sea animals rely on mineral nodules as a stable surface to settle on, and decades of research show that mining activity can have a “persistent” biological impact.

The ISA talks on deep-sea mining regulation are expected to resume in Q1 of next year.