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.
The scientists said their work was independent and that the company was able to view the results before publication but was not allowed to alter them.
The team compared biodiversity two years before and two months after the test mining that drove machines for 80km on the seafloor.
They looked specifically at animals 0.3mm – 2cm in size, such as worms, sea spiders, snails, and clams.
In the tracks of the vehicle, the number of animals fell by 37% and the diversity of species by 32%.
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, told BBC News.
Deep sea mining is controversial. At the heart of the debate is a difficult problem.
The latest research took place in the Clarion-Clipperton Zone, a 6m sq km area of the Pacific Ocean estimated to hold over 21bn tonnes of nickel, cobalt, and copper-rich polymetallic nodules.
The world needs these critical minerals for renewable energy technologies to tackle climate change. They are essential components in solar panels, wind turbines, and electric vehicles.
Some fear that before we have the chance to explore the full nature of life in the undiscovered deep ocean, it could be endangered. Oceans play a critical role in regulating our planet and are already at severe risk from rising temperatures.
However, experts do not think that the findings are good news for mining companies. As Dr Patrick Schröder stated, the significant impact observed in test phases suggests that large-scale operations may be even more damaging.
