The Battle for the Seafloor: Mining Nodules vs. Marine Life

The transition to renewable energy faces a complicated geographical problem. While the world demands more electric vehicles (EVs) and green infrastructure, the metals required to build them are becoming harder to find on land. This scarcity has turned eyes toward the bottom of the ocean, specifically the abyssal plain, where trillions of dollars worth of battery metals sit in total darkness. However, a fierce debate has erupted between mining corporations, international regulators, and marine biologists over the true cost of harvesting these resources.

The Prize: What Are Polymetallic Nodules?

The center of this conflict involves potato-sized rocks known as polymetallic nodules. These concretions take millions of years to form and are scattered across the ocean floor, typically at depths of 3,500 to 6,000 meters. They are rich in high-demand minerals:

• Nickel: Crucial for high-density EV batteries.
• Cobalt: Used to stabilize lithium-ion batteries.
• Manganese: Essential for steel and battery cathodes.
• Copper: The backbone of electrical wiring.

The primary target for these nodules is the Clarion-Clipperton Zone (CCZ), a massive stretch of the Pacific Ocean between Hawaii and Mexico. It is estimated that the CCZ contains more nickel, manganese, and cobalt than all known terrestrial reserves combined.

Leading the charge to extract these nodules is The Metals Company (TMC), a Canadian miner partnered with the Pacific island nation of Nauru. TMC argues that collecting loose rocks from the seafloor is less damaging than razing rainforests in Indonesia for nickel or relying on child labor in the Democratic Republic of Congo for cobalt.

The Regulator: The International Seabed Authority (ISA)

The International Seabed Authority (ISA), a UN-affiliated body based in Kingston, Jamaica, controls mining activities in international waters. The ISA is currently in a difficult position. It is tasked with two potentially contradictory mandates: protecting the marine environment and organizing the commercialization of seabed resources.

The timeline accelerated recently due to a legal trigger known as the “two-year rule.” In 2021, Nauru notified the ISA of its intention to start mining, which forced the regulatory body to finalize a “Mining Code” by July 2023. The ISA missed this deadline.

During the chaotic meetings in July and August 2024, the ISA Assembly failed to finalize the regulations again. They have now pushed the target date to 2025. Until a strict mining code is adopted, the legal status of commercial extraction remains in a gray area, creating tension between nations eager to mine and those calling for a pause.

The "Dark Oxygen" Discovery

A scientific bombshell dropped in July 2024 fundamentally changed the debate. A study published in the journal Nature, led by Professor Andrew Sweetman of the Scottish Association for Marine Science, revealed that polymetallic nodules are not just inert rocks. They are electrically charged and act as “geobatteries.”

Sweetman and his team discovered that these nodules can split seawater into hydrogen and oxygen through electrolysis. This phenomenon, dubbed “Dark Oxygen,” means oxygen is being produced in the deep sea without sunlight.

This finding challenges the long-held assumption that deep-ocean life relies solely on oxygen drifting down from the surface. If nodules are a primary oxygen source for abyssal ecosystems, removing them could suffocate life on the seafloor. This discovery has given ammunition to conservationists and countries calling for a moratorium.

Geopolitics and Corporate hesitation

The world is split on how to proceed. The debate has moved beyond environmentalists versus miners; it is now a diplomatic standoff.

The Pro-Mining Bloc

• Norway: In early 2024, the Norwegian parliament voted to open its own territorial waters to deep-sea mining exploration, becoming the first country to do so officially.
• China: As a dominant player in terrestrial rare earth processing, China holds several exploration contracts in the CCZ and is actively developing mining technology.
• Nauru: This small island nation views deep-sea mining as a critical economic lifeline and continues to pressure the ISA to approve commercial licenses.

The Moratorium Bloc

Over 25 countries have called for a precautionary pause, moratorium, or ban on deep-sea mining until the environmental impacts are fully understood.

• France: President Emmanuel Macron has explicitly called for a ban on extraction in the high seas.
• United Kingdom: Recently shifted its stance to support a moratorium on granting exploitation licenses.
• Corporate Boycotts: Major brands including BMW, Volvo, Samsung, and Google have pledged not to use deep-sea minerals in their supply chains, citing environmental concerns.

Environmental Risks Beyond Oxygen

While “Dark Oxygen” is the newest concern, marine biologists have warned of other dangers for years.

Sediment Plumes Mining machines, which look like massive combines, will vacuum the seafloor. This process kicks up massive clouds of sediment. These plumes can drift for miles, clogging the delicate feeding structures of filter feeders like sponges and corals.

Noise Pollution Sound travels effectively underwater. The noise from mining machinery and riser pipes could disrupt the communication and navigation of deep-diving whale species.

Biodiversity Loss The CCZ is not a desert. It is home to thousands of species, many of which are new to science. This includes the “Casper” ghost octopus, which lays its eggs specifically on the stalks of sponges that grow on polymetallic nodules. Removing the nodules removes their breeding ground.

What Happens Next?

The next critical moment will occur at the ISA meetings in 2025. If the Mining Code is finalized, The Metals Company expects to apply for a commercial exploitation license shortly after. If the regulations are stalled again, Nauru may attempt to force approval under provisional laws.

The industry is watching closely. If deep-sea mining proves viable and legal, it could crash the price of battery metals and reshape global supply chains. If it is banned or heavily restricted, the world will need to double down on recycling and finding terrestrial sources for the green energy transition.

Frequently Asked Questions

What are the main metals found in deep-sea nodules? The primary metals are nickel, cobalt, manganese, and copper. These are critical components for electric vehicle batteries and renewable energy storage systems.

Who regulates mining in international waters? The International Seabed Authority (ISA), an autonomous international organization established under the 1982 United Nations Convention on the Law of the Sea (UNCLOS), regulates these activities.

What is the “Dark Oxygen” discovery? In 2024, scientists discovered that polymetallic nodules on the seafloor generate a weak electric charge that splits seawater molecules, producing oxygen in total darkness. This suggests nodules play a vital role in deep-sea ecosystem health.

Which countries support deep-sea mining? Nauru, China, and Norway are among the most vocal supporters of moving forward with exploration and eventual extraction.

Have any companies started commercial mining yet? No. Commercial mining has not started. Companies like The Metals Company have conducted successful collection tests, but they are waiting for the ISA to finalize regulations and grant exploitation licenses.