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.
They found that the number of animals in the tracks of the vehicles was reduced by 37% compared to untouched areas.
The researchers discovered over 4,000 animals, 90% of which were new species, living on the seafloor in a remote area of the Pacific Ocean.
While vast amounts of critical minerals needed for green technologies could be locked in the deep ocean, deep sea mining in international waters remains controversial and currently not permitted until more is known about the environmental impacts.
The research conducted by scientists at the Natural History Museum in London, the UK National Oceanography Centre, and the University of Gothenburg was commissioned by deep sea mining company The Metals Company. They stated their work was independent, allowing the company to view results pre-publication without altering them.
Focusing on biodiversity two years before and two months after test mining over 80km of seafloor, the team examined animals sized between 0.3mm and 2cm, including worms and clams. They revealed a 37% drop in overall numbers and a 32% decline in species diversity within the tracks of the mining vehicles.
According to lead author Eva Stewart, the impact stems from the removal of the top five centimeters of sediment where most animals reside.
Dr. Guadalupe Bribiesca-Contreras from the National Oceanography Centre noted that while some animals might move away from mining areas, their return isn't guaranteed.
However, regions nearby didn't show a decrease in animal abundance, suggesting that not all species are uniformly affected by sediment clouds created during mining.
Commenting on the implications, Dr. Patrick Schröder from Chatham House warns that the current mining practices are too damaging for large-scale commercial exploration. The study was conducted in the Clarion-Clipperton Zone, a significant site for potential mineral extraction, amid global climate change concerns.
Despite an increasing global demand for these minerals for renewable energy technologies, the International Seabed Authority (ISA) has not approved commercial mining yet but has issued exploration licenses. Some countries have backed a temporary ban on mining until further research informs safe practices.
The research findings are available in the scientific journal Nature Ecology and Evolution.
