Noise pollution from deep-sea mines threatens whales: study

Scientists warned on Tuesday that controversial seafloor mining could pose a significant threat to ocean ecosystems, especially blue whales and other cetaceans already under pressure from shipping, pollution and climate change.

A study in the journal Frontiers in Marine Science found that commercial-scale extraction of valuable minerals from the ocean floor, which could begin later this year, would damage habitats and disrupt the way cetaceans communicate.

Previous research has detailed the likely destructive impact of deep-sea mining on the ocean floor. The new analysis from the University of Exeter and Greenpeace Research Laboratories shifts the spotlight to marine megafauna and noise pollution.

“Cetaceans rely on sound for every aspect of their behaviour, including foraging, breeding and navigation,” Kirsten Thompson, the study’s lead author and a lecturer in marine mammal biology at the University of Exeter, told AFP.

“Therefore, noise pollution from deep-sea mining is a particular concern.”

The report points to overlap between the frequencies at which cetaceans communicate and the sound that would be generated by drilling, dredging and the acoustic telemetry needed to remotely control vehicles that operate seafloor mining.

This phenomenon, called “auditory masking,” has previously been shown to disrupt marine mammal communication and alter their behavior.

Underwater noise generated by industrial or military operations can cause foraging whales to surface faster than normal, increasing the risk of gas bubbles forming in the bloodstream, which in turn can lead to stranding and death.

Other research has found that human-induced noise increases the risk of separation between humpback whales and their calves, which communicate through silent vocalizations.

– ‘Two Year Rule’ –

The new findings come with some caveats.

Since seafloor mining is not yet allowed anywhere in the oceans, Thompson and her team had no real-world data to draw from.

So they used proxies from other industries to estimate the expected noise from industrial mining activities on the seafloor.

Thompson also pointed to knowledge gaps in the distribution of marine mammal species, primarily due to the high cost of biological research across vast oceans.

The impact of deep-sea mining on cetaceans is expected to be particularly acute in the Pacific Ocean’s Clarion-Clipperton Zone, a habitat for some two dozen cetaceans, including baleen whales, beaked whales, sperm whales and Risso’s dolphins.

The region is poised to become home to the world’s largest extraction of manganese nodule, a mineral crucial in electric car batteries.

The small island nation of Nauru, in particular, sees deep-sea mining as a potentially lucrative revenue stream for climate adaptation in the face of rising sea levels and increasingly powerful storms.

In June 2021, the government of Nauru introduced a rule requiring the International Seabed Authority (ISA) – the UN body that regulates deep-sea exploration and exploitation in areas beyond national jurisdiction – to fully implement mining regulations within two years. sea ​​worldwide.

Under this so-called “two-year rule”, mining could continue in July of this year with the rules the ISA has formulated by then.

“Given the imminent threat the two-year rule poses to ocean conservation, we suggest there is no time to lose,” Thompson said.


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