More than a third of animals affected in deep-sea mining trials

Machines that mine minerals in the deep sea have been found to be causing significant damage to life on the seafloor, scientists conducting the largest study of its kind say.

Scientists say the number of animals found on the vehicle tracks dropped by 37% compared with unaffected areas.

Researchers have discovered more than 4,000 animals, 90 percent of which are new species, living on the seafloor in remote areas of the Pacific.

Huge amounts of critical minerals needed for green technologies may be locked up in the deep sea, but deep-sea mining in international waters is highly controversial and currently not allowed until more is known about the environmental impact.

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

The scientists say their work is independent and the company can review the results before publishing but is not allowed to change them.

The team compared biodiversity two years before and two months after trial mining, during which the machine traveled 80 kilometers on the seafloor.

They looked specifically at animals ranging in size from 0.3 millimeters to 2 centimeters, such as worms, sea spiders, snails and clams.

The number of animals dropped by 37% and species diversity dropped by 32% during vehicle driving tracks.

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

Dr. Guadalupe Bribiesca-Contreras of the National Oceanographic Center said: “Even if they are not killed by the machines, pollution from mining operations will slowly kill some less resistant species.”

Some animals may have left, but “whether they will return after being disturbed is another question,” she added.

However, near the ruts, in areas where sediment clouds have settled, the number of animals did not decrease.

Dr Adrian Glover, a research scientist at the Natural History Museum, told BBC News: “We expected there might be a larger impact but[we didn’t]see much, just a shift in the dominance of one species relative to another.”

“We are encouraged by these data,” a spokesman for the metals company told BBC News.

“Campaigners have warned for years that our impacts would spread thousands of kilometers beyond mining sites, and data shows that any biodiversity impacts are limited to areas directly mined,” they added.

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

Dr Patrick Schroeder, senior fellow at the Center for Environment and Society at think tank Chatham House, told BBC News: “I think this study shows that current logging techniques are too destructive for large-scale commercial exploration.”

“These are just tests and the impact is huge. 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 question.

The latest research was conducted in the Clarion-Clipperton Zone, a 6 million square kilometer area in the Pacific that is estimated to contain more than 21 billion tons of polymetallic nodules rich in nickel, cobalt and copper.

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

International Energy Agency forecast By 2040, demand for minerals is likely to at least double.

These minerals have to come from somewhere, but some scientists and environmental groups are seriously concerned that deep-sea mining could cause untold damage.

Some worry that it could be threatened before we have a chance to explore the full nature of life in the undiscovered deep.

The ocean plays a key role in regulating our planet and is already at serious risk from rising temperatures.

The International Seabed Authority (ISA), which regulates activities in international waters, has not yet approved 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 waters including the Arctic.

But in April, US President Donald Trump called for speeding up domestic and international projects as the United States looks to secure supplies of minerals for weapons.

If the ISA decides that current mining techniques are too destructive, companies could try to develop less invasive methods of extracting nodules from the seafloor.

The research was published in the scientific journal Nature Ecology & Evolution.