Machines mining minerals in the deep ocean have been found to cause significant damage to life on the seabed, scientists carrying out the largest study of its kind say.
The number of animals found in the tracks of the vehicles was reduced by 37% compared to untouched areas, according to the scientists.
The researchers discovered more than 4,000 animals, 90% of which were new species, living on the seafloor in a remote area of the Pacific Ocean.
Vast amounts of critical minerals needed for green technologies could be locked in the deep ocean, but deep sea mining in international waters is very controversial and currently not permitted until more is known about the environmental impacts.
The research by scientists at the Natural History Museum in London, the UK National Oceanography Centre and the University of Gothenburg was conducted at the request of deep sea mining company The Metals Company. Scientists insist that their work was independent and that the company could view the results before publication but was forbidden from altering them.
The team compared biodiversity two years before and two months after the mining tests that drove machines for 80km on the seafloor. They specifically observed animals 0.3mm – 2cm in size, such as worms, sea spiders, snails and clams.
The number of animals fell by 37% and the diversity of species by 32% in the tracks of the vehicle. 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, said lead author Eva Stewart, PhD student at the Natural History Museum.
Dr. Guadalupe Bribiesca-Contreras from the National Oceanography Centre warned that pollution from mining could slowly harm less resilient species, even if they weren't directly killed by the machinery.
Conversely, more than 30 countries, including the UK and France, currently support a temporary ban on deep-sea mining until more research highlights its impacts.
Despite promising data proposed by companies like The Metals Company, experts remain skeptical, asserting that the current technologies used in harvesting might be too destructive.
The research suggesting significant effects from test mining raises concerns about potential large-scale exploitation in these fragile ecosystems.
The International Seabed Authority (ISA) has yet to approve commercial mining but has issued exploration licences as the global demand for these critical minerals escalates in renewable energy technologies.
