Over a third of animals lost in test deep sea mining

Machines that extract minerals from the ocean depths have been found to cause significant damage to life on the seabed, according to scientists leading the largest study of its kind.

They found that the number of animals found in vehicle tracks was reduced by 37% compared to untouched areas.

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.

Large quantities of essential minerals needed for green technologies could be locked away in the ocean depths, but deep-sea mining in international waters is highly controversial and currently banned until more is known about the environmental impacts.

The research by scientists from the Natural History Museum in London, the UK National Oceanographic Center and the University of Gothenburg was carried out at the request of deep sea mining company The Metals Company.

The scientists said their work was independent and the company was able to view the results before publication but was not allowed to change them.

The team compared biodiversity two years before and two months after the mining test that drove machines 80 km across the seabed.

They looked specifically at animals measuring between 0.3 mm and 2 cm, such as worms, sea spiders, snails and clams.

In the vehicle tracks, the number of animals decreased by 37% and species diversity by 32%.

“The machine removes about the top five centimeters of sediment. That’s where most of the animals live. So obviously if you remove the sediment you also remove the animals that are there,” lead author Eva Stewart, a doctoral student at the Natural History Museum and the University of Southampton, told BBC News.

“Even if they are not killed by the machine, pollution from mining operations could slowly kill off some less resilient species,” said Dr. Guadalupe Bribiesca-Contreras of the National Oceanographic Center.

Some animals might have wandered off, but “whether or not they return after a disturbance is another question,” she added.

However, in areas near vehicle tracks, where clouds of sediment settled, animal abundance did not decrease.

“We were expecting maybe a slightly bigger impact, but [we didn’t] “We’re seeing a lot of things, just a shift where one species was dominant over others,” Dr Adrian Glover, a researcher at the Natural History Museum, told BBC News.

“We are encouraged by this data,” a spokesperson for The Metals Company told BBC News.

“After years of activist alarms that our impacts extend thousands of kilometers beyond the mining site, the data shows that any impacts on biodiversity are limited to the directly mined area,” they said. added.

But some experts don’t think this is good news for mining companies.

“I think the study shows that current harvesting technologies are too damaging to allow large-scale commercial exploration,” Dr Patrick Schröder, a senior researcher at the Environment and Society Center at think tank Chatham House, told BBC News.

“It was just testing and the impact was significant. If they did it on a large scale it would be even more damaging,” he added.

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 6 million square kilometer area of ​​the Pacific Ocean that is estimated to contain more than 21 billion tonnes of polymetallic nodules rich in nickel, cobalt and copper.

The world needs these essential minerals for renewable energy technologies to combat climate change. They are essential components in solar panels, wind turbines and electric vehicles, for example.

The International Energy Agency predicts that demand for minerals could at least double by 2040.

Minerals have to come from somewhere, but some scientists and environmental groups seriously fear that deep-sea mining could cause untold damage.

Some fear that before we have the chance to explore the full nature of life in the still-undiscovered ocean depths, it will be threatened.

The oceans play an essential role in regulating our planet and are already seriously threatened by rising temperatures.

The International Seabed Authority (ISA), which governs activities in international waters, has yet to approve commercial mining although it has issued 31 exploration licenses.

A total of 37 countries, including the UK and France, support a temporary ban on mining.

This week, Norway postponed mining plans in its waters, including in the Arctic.

But in April, U.S. President Donald Trump called for accelerating domestic and international projects as the United States wants to secure supplies of minerals for weapons manufacturing.

If the ISA concludes that current mining techniques are too destructive, companies could try to develop less intrusive ways to extract the nodules from the seabed.

The research is published in the scientific journal Nature Ecology and Evolution.