The deep sea is a mysterious and largely unexplored world, but now companies are pushing to begin full-scale mining of the ocean floor as early as this year. The industry’s largely untested nature has raised fresh questions about the potential harms it could do to the fragile marine ecosystems.

Recently, video footage from a deep-sea mining test, showing sediment discharging into the ocean, has raised even more questions. The Metals Company (TMC), a Canadian mining firm that is one of the leading industry players, spent September to November of last year testing its underwater extraction vehicle in the Clarion Clipperton Fracture Zone, a section of the Pacific Ocean between Mexico and Hawaii. But a group of scientists hired by the company to monitor its operations, concerned by what they saw, posted a video of what they said was a flawed process that accidentally released sediment into the ocean.

The Risks of Deep-Sea Mining

As the push for deep-sea mining intensifies, experts are increasingly concerned that companies will kick up clouds of sediment, which could be laden with toxic heavy metals that may harm marine life. At least 700 scientists – along with France, Germany and Chile – are calling for a moratorium on deep-sea mining.

In a post to its website, TMC acknowledged the incident, but framed the discharge from its cyclone separator as a “minor event” in which “a small amount” of sediment and nodule fragments spilled into the ocean. The company said it fixed the issue in its equipment to prevent further overflows and concluded that the incident “did not have the potential to cause serious harm”.

The Potential Profits of Deep-Sea Mining

Heavyweight investors, including the Danish logistics giant Maersk and the commodity multinational Glencore, are now looking hungrily at deep-sea mining, underscoring the hopes that industry has for unearthing new sources of critical metals, such as copper, cobalt and nickel. Investor materials from TMC suggest the company believes its mine sites in the Pacific could produce more than $30bn (£24bn) in profits over the next 20 years with minimal harm to the environment.

The Challenges of Deep-Sea Mining

While many of the technologies used in deep-sea mining were developed decades ago, the inadvertent discharge during testing highlights the challenges of fine-tuning equipment for use in the field. Scientists hired by TMC and its subcontractors say the sediment monitoring plan, critical for the company’s approval to begin mining, was developed without full consideration of how sediment plumes (debris kicked up from mining the sea floor) actually work, and that those tasked with overseeing the efforts had little experience working with the plumes.

The Impact of Deep-Sea Mining

Critics have long feared the plumes of sediment created from extraction could seriously harm marine ecosystems by limiting light penetration and releasing harmful toxins. “We don’t know what the consequences of those problems were under the surface of the sea,” said Catherine Coumans of MiningWatch Canada. “We’re only seeing the tip of the iceberg. We’re not getting transparency.”

As the push for deep-sea mining intensifies, it’s more important than ever to consider the potential risks and harms that could be caused by mining the ocean floor. With so much at stake, it’s essential to ensure that all safety protocols are strictly adhered to and that any potential environmental damage is minimized. Only then can we ensure that the deep sea remains a safe and healthy ecosystem for generations to come.