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 found in the tracks of the vehicles was reduced by 37% compared to untouched areas.
The researchers found over 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 stated their work was independent, allowing the company to view results before publication but prohibiting alterations.
The team compared biodiversity two years before and two months after the test mining that drove machines for 80km on the seafloor, specifically looking 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 species diversity by 32%.
Lead author Eva Stewart, a Ph.D. student at the Natural History Museum, noted, The machine removes about the top five centimeters of sediment, which is where most of the animals live. Removing the sediment naturally means removing the animals in it too..
Dr. Guadalupe Bribiesca-Contreras from the National Oceanography Centre expressed that pollution from the mining operations could slowly kill less resilient species, even if they were not directly harmed during the mining process.
Interestingly, the researchers found that in areas outside vehicle tracks, where clouds of sediment had settled, there was no significant decrease in the abundance of marine animals.
“We were expecting possibly a bit more impact, but we didn't see that; just a shift in species dominance,” Dr. Adrian Glover from the Natural History Museum remarked.
A spokesperson for The Metals Company welcomed the findings, stating, After years of activist alarm regarding our impacts, the data show that biodiversity impacts are limited to directly mined areas. However, some experts caution that this study highlights the unsustainable nature of current mining technologies.
Dr. Patrick Schröder from Chatham House stated that the significant impact observed from tests suggests large-scale commercial exploration could lead to even more damage.
As demand for critical minerals is predicted to double by 2040, the challenge lies in balancing ecological health with the need for these resources for renewable technologies.
The International Seabed Authority (ISA) has issued 31 exploratory licenses but has yet to approve any commercial mining endeavors, with many countries, including the UK and France, advocating for a temporary ban. There is a growing awareness that the exploration of deep-sea biodiversity must precede any mining activities to prevent potential disasters.
The research is published in the scientific journal Nature Ecology and Evolution.
