The race is on to figure out how to protect the seabed as deep-sea miners try to extract minerals like nickel, cobalt and copper from the seabed. But there is a potential risk to the deep-sea environment that tends to stay under the radar. Not only will mining dredge the seabed, it will also create a lot of noise, which poses its own problems for marine life, according to a new article published in the journal Science.
Mining minerals in the deep sea has been talked about for decades, and that future is almost here. Fueled by a need for more minerals used in everyday devices and batteries, initial efforts to prospect for these resources in polymetallic nodules at the bottom of the ocean could begin in earnest as early as next year. The noise from these operations could even affect marine life hundreds of miles away, the new paper’s authors found.
Within about 6 kilometers (3.73 miles) of a mine, the noise could be the equivalent of a rock concert or even louder. That exceeds the 120 dB threshold that the US National Marine Fisheries Service says could negatively impact marine mammal behavior. The noise travels up to 500 kilometers (310 miles) away, where it is weaker in fair weather but still louder than ambient noise levels.
“The biggest surprise for me was how far the ambient noise levels are likely to be exceeded,” says Craig Smith, co-author of the publication and professor of oceanography at the University of Hawaii. To make matters worse, the mining noise could be non-stop. “This noise is expected to be produced 24/7 for years, maybe even decades,” says Smith The edge.
And unlike the noise in busy ports, which is mainly heard at the water’s surface, mining creates noise all the way down to the seabed. There is noise from ships above, dredgers below and pumps bringing nodules and sediment to the surface.
As a result, migrating whales may find it more difficult to communicate. Or whales and other animals could choose to avoid these areas altogether, which could even affect their migration.
Still, researchers don’t know exactly how this will affect marine life — and a big part of the problem is that there’s still so much we don’t know about marine life abyss of the ocean. The vast majority of animal researchers brought back from expeditions to these depths — 4,000 meters (13,123 feet) or deeper — are entirely new to science, according to Smith.
There are crustaceans, worms, molluscs, anemones and more – and Smith would like to see more research into how sensitive these creatures are to noise. Without sunlight at these depths, some animals have evolved sensory systems that allow them to use vibration or sound to evade predators or find mates and prey.
Smith and his colleagues made predictions based on models because mining hasn’t started yet, and they couldn’t make real-world observations. They focused on a region that could soon be a hotspot for deep-sea mining called the Clarion-Clipperton Zone, which lies between Hawaii and Mexico. This zone is rich in polymetallic nodules, lumpy black rock-like things on the seabed containing metals that are increasingly being sought for the manufacture of electric vehicle batteries.
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Last year, the small island nation of Nauru announced plans to sponsor efforts to dismantle the Clarion-Clipperton Zone. This triggered a clause in the United Nations Convention on the Law of the Sea, which obliges the International Seabed Authority to come up with new regulations for mining the nodules by the middle of next year.
Since then, hundreds of scientists have pushed to stop mining until they better understand what it could do for the environment. Last week, leaders of some island nations — including Palau, Fiji and Samoa — also called for a moratorium on deep-sea mining. Mining digs up and buries seabed habitats. Plunging in without a good understanding of the risks, they warn, could even wipe out ecologically important species before they’re even discovered.
Smith and his co-authors are also urging mining companies to release more data on the noise made by their mining equipment. Progress over the next year “without data transparency and strict standards and guidelines would represent the start of a large-scale, uncontrolled experiment,” the paper said.