Unforeseen perils to marine life posed by deep-sea mining operations.
Dive into the abyssal wilds of the ocean - a realm so pitch-black and pressurized it feels like an alien world. Creatures that emit light and survive under incredible strain call this the midwater zone, an ecosystem sprawling across our planet from 200 meters below the ocean's surface. Comprising the twilight and midnight layers, this hidden biome is home to peculiar and ethereal lifeforms that flourish in the near absence of sunlight. This underground banquet offers sustenance not only for the ocean's heavies like whales but also for commercially valuable species such as tuna. But, our clumsy human hands seem poised to wreak havoc on this unique underworld.
As the hunger for electric car batteries and smartphones skyrockets, mining companies have set their sights on the deep sea, where precious metals like nickel and cobalt can be found in spud-size nodules, scattered on the ocean floor. Deep-sea mining has been researched and experimented with for the past four decades, and we've learned that extracting these nodules can put seafloor denizens in peril. However, the process may pose a danger not only to what lives beneath but also to creatures residing in the midwater ecosystem above it.
If future deep-sea mining operations send tumultuous sediment plumes into the water column, as proposed, these waves of debris could disrupt midwater animals' feeding, disrupt food webs, and alter their behaviors. As an oceanographer studying marine life in a Pacific region teeming with these precious nodules, I am worried about humanity's reckless disregard for the delicate balance of this ecosystem. Are we willing to plunge parts of an ecosystem we barely comprehend into chaos for resources crucial to our collective future?
A veritable treasure trove of these nodules can be found beneath the Pacific Ocean, southeast of Hawaii, in the hidden recesses of the Clarion-Clipperton Zone (CCZ). These nodules form when metals gather around a core, such as a piece of shell or tooth from a shark. Growing at a sloth-like pace of a few millimeters per million years, these nodules contain a wealth of rare minerals like nickel, cobalt, and manganese – essential ingredients for batteries, smartphones, wind turbines, and military hardware.
As the demand for these technologies spikes, mining companies intend to exploit the CCZ, joined by a few other regions with similar nodules scattered around the globe. For now, only test mining has been attempted, but plans for full-scale commercial mining are racing forward. Exploratory deep-sea mining began in the 1970s, and the International Seabed Authority was established in 1994 under the United Nations Convention on the Law of the Sea to govern it.
However, it wasn't until 2022 that The Metals Company and Nauru Ocean Resources Inc. demonstrated the first fully integrated nodule collection system in the CCZ. The companies are now readying themselves for large-scale mining operations in the region, but international authorities are still debating regulations. The Metals Company appealed to President Donald Trump, praising his order on April 24, 2022, which expedited U.S.-issued licenses for seabed mining outside national waters under the Deep Seabed Hard Mineral Resources Act. This move, however, runs counter to the International Seabed Authority's stance, which staunchly opposes it.
Several countries have argued for a moratorium on seabed mining until its ramifications are better understood. The mining process is invasive, disturbing marine organisms' habitats and threatening biodiversity, potentially causing irreversible harm to seafloor ecosystems. When collected, the nodules are lifted with seawater and sediment via a pipe to a ship, where they are separated from waste. The discarded slurry of waste, water, and crushed nodules is then dumped back into the water column, creating plumes that could disrupt marine life and upset ecosystems.
However, we're still grappling with the unknowns – the ocean is in a constant state of flux, changing with currents, and we don't fully grasp how these plumes will behave once released into the midwater zone. These dust clouds could sprawl over huge swathes, engulfing everything in their path like a monstrous volcanic eruption, but not of lava – of fine, murky sediments. These intrusions could harm midwater life, disrupt feeding patterns, and potentially lead to the collapse of entire ecosystems.
The midwater ecosystem is a hotbed of zooplankton – tiny, drifting creatures – and micronekton, including small fish, squid, and crustaceans that feast on zooplankton. Fine sediments could clog respiratory structures in fish, cripple the feeding mechanisms of filter feeders, and dilute food resources with poor nutrients. This turbulence might also disturb the visual cues relied upon by luminescent organisms and visual predators. Delicate creatures like jellyfish and siphonophores – long, gelatinous beings – could find their buoyancy and survival at risk from sediment accumulation.
In addition, noise pollution from machinery could throw a wrench in how species communicate and navigate, further complicating matters. Disturbances like these have the potential to unleash havoc on ecosystems, extending far beyond the discharge depth. The decline of zooplankton populations could impact fish and other marine life relying on them for sustenance. The midwater zone also plays a significant role in Earth's climate, as phytoplankton capture carbon from the atmosphere, which zooplankton consume and transfer through the food chain.
Despite the escalating intrigue surrounding deep-sea mining, much of the deep ocean remains shrouded in mystery, particularly the midwater zone. A 2023 study found that 88 to 92% of species in the CCZ have yet to be discovered by science. Current mining regulations prioritize the seafloor, overlooking broader ecosystem impacts. In July 2025, the International Seabed Authority plans to discuss critical decisions regarding future seabed mining, including rules addressing mining waste discharge depths and environmental protection. These decisions could set the stage for large-scale commercial mining in ecologically important regions like the CCZ. However, the consequences for marine life remain unclear without comprehensive studies on the impact of seafloor mining techniques.
Alexus Cazares-Nuesser, a Ph.D. candidate in Biological Oceanography at the University of Hawaii, is one of many scientists ringing the alarm bell. The Conversation, an independent and nonprofit source of news, analysis, and commentary from academic experts, provides a platform for such warnings. It's high time the world begins to grasp the gravity of unchecked deep-sea mining in the CCZ and take decisive action to protect this fragile and mysterious ecosystem.
- The military might depend on technologies that require rare minerals, such as nickel, cobalt, and manganese, found in deep-sea nodules.
- The environment is under threat due to deep-sea mining activities aimed at extracting these valuable minerals from the ocean floor.
- The tech industry's growing demand for smartphones and electric car batteries is driving the interest in deep-sea mining.
- As a national obligation, it is crucial to consider the environmental impacts of deep-sea mining on our planet's ecosystems.
- Science plays a pivotal role in studying and understanding the complex effects of deep-sea mining on marine life and ecosystems.
- Health-and-wellness and fitness-and-exercise industries may also be affected indirectly by the disruption of underwater food chains due to deep-sea mining.
- Climate change could be intensified if the carbon-capturing abilities of the midwater ecosystem are compromised by deep-sea mining activities.
- Environmental-science research has shown that deep-sea mining could lead to habitat destruction, biodiversity loss, and irreversible harm to seafloor ecosystems.
- Artificial Intelligence (AI) could potentially help in monitoring and mitigating the effects of deep-sea mining on marine environments.
- Education-and-self-development programs can raise awareness about the importance of protecting the deep ocean, particularly the midwater zone, and the potential ramifications of unchecked deep-sea mining in ecologically sensitive regions like the CCZ.
