The Clarion-Clipperton Zone, or CCZ, is a roughly six-million-square-kilometer stretch of abyssal seafloor in the central-eastern Pacific Ocean, located between Hawaii and Mexico and bounded by two geological fracture zones that give it its name. It matters because it sits at the intersection of several urgent global questions: it holds one of the largest known deposits of metals needed for batteries and clean-energy technology, it harbors deep-sea ecosystems that science is only beginning to understand, and it is the focus of an intensifying international debate over whether and how to mine the ocean floor. The tension between resource extraction and ecological protection makes the CCZ one of the most consequential pieces of real estate on the planet, even though almost nobody lives anywhere near it.
Where It Is and What the Seafloor Looks Like
The CCZ stretches across the Pacific between roughly 5° and 20° North latitude and 115° to 160° West longitude, covering more than one percent of Earth’s entire surface area.1Progress in Oceanography. Environment, ecology, and potential effectiveness of an area protected from deep-sea mining (Clarion Clipperton Zone, abyssal Pacific) To put that in perspective, it is larger than the European Union. The two fracture zones that bracket it, the Clarion Fracture Zone to the north and the Clipperton Fracture Zone to the south, are tectonic scars in the oceanic crust that run roughly east-west across the Pacific plate.
The seafloor itself is not flat. Water depths range from about 3,400 meters on the tallest seamounts down to 4,400 meters or more in the deepest basins.1Progress in Oceanography. Environment, ecology, and potential effectiveness of an area protected from deep-sea mining (Clarion Clipperton Zone, abyssal Pacific) The terrain includes chains of underwater mountains and knolls, ridges separated by troughs in a geological pattern called horst-and-graben structure, and broad plains of soft sediment. This mix of topography matters, because the types of organisms that live on a seamount slope differ from those in the flat abyssal plains, and the distribution of mineral deposits varies with the landscape too.
The Potato-Sized Mineral Deposits
What makes the CCZ economically interesting are polymetallic nodules: dark, roughly potato-sized lumps of metal-rich rock scattered across the seafloor like loose cobblestones. They sit unattached on the sediment surface, which is part of what makes them tempting to harvest compared to minerals locked in hard rock underground. The nodules contain four metals that are critical for modern technology: nickel, cobalt, manganese, and copper.2Journal of Industrial Ecology. Deep‐sea nodules versus land ores: A comparative systems analysis of mining and processing wastes for battery‐metal supply chains All four are essential ingredients in lithium-ion batteries, stainless steel, and other products central to the energy transition away from fossil fuels.
Nodules grow extraordinarily slowly, accreting layers of metal oxides from seawater and from chemical reactions within the sediment at a rate of just millimeters per million years. Research on CCZ nodules has identified distinct types based on how they form. Some are primarily hydrogenetic, meaning metals precipitate directly from the surrounding seawater, and these tend to be small, smooth, and especially rich in cobalt and rare earth elements. Others grow larger and develop bumpy, botryoidal surfaces, with higher ratios of manganese to iron and somewhat different metal profiles.3Ore Geology Reviews. Fe-Mn nodule morphotypes from the NE Clarion-Clipperton Fracture Zone, Pacific Ocean: Comparison of mineralogy, geochemistry and genesis The practical upshot is that a single mining area can contain nodules with varying concentrations of target metals, and the combined trace-metal content of nickel, copper, and cobalt in CCZ nodules can exceed two percent of their total weight.
Why the World Wants These Metals
Global demand for the metals locked in CCZ nodules is rising fast because they are the same metals needed for electric vehicle batteries, grid-scale energy storage, and renewable-energy infrastructure. Nickel and cobalt are key cathode materials in the lithium-ion batteries that power everything from phones to freight trucks. Manganese goes into steel alloys and newer battery chemistries. Copper is the backbone of electrical wiring and motors. Mining these metals on land comes with its own environmental and geopolitical complications: cobalt mining, for instance, is heavily concentrated in the Democratic Republic of Congo, and nickel extraction in tropical forests generates its own ecological damage. Deep-sea mining has been framed by proponents as a way to diversify global mineral supply and reduce reliance on geopolitically sensitive land-based sources.4PubMed. Uncharted depths: Navigating the energy security potential of deep-sea mining
Whether that trade-off actually works out depends entirely on how much environmental damage deep-sea mining causes compared with the terrestrial alternative. This is where the biology of the CCZ becomes central to the conversation.
A Surprising Amount of Life in the Dark
The abyssal plains of the CCZ sit far below the reach of sunlight, under crushing pressure, in near-freezing water. For a long time, the deep sea was assumed to be a biological desert. That assumption has turned out to be spectacularly wrong. Every expedition to the CCZ seems to discover new species. One study of the zone’s megafauna, the animals large enough to see in photographs, found that seven of twelve collected species were previously unknown to science, including three entirely new genera of corals and sponges.5Scientific Reports. Insights into the abundance and diversity of abyssal megafauna in a polymetallic-nodule region in the eastern Clarion-Clipperton Zone These are not just slightly different variations on known animals; entire branches of the tree of life have been hiding on the abyssal seafloor.
The nodules themselves are a big part of why the CCZ supports so much life. In an environment where almost everything is soft sediment, a hard surface is precious real estate. Corals, sponges, bryozoans, and other organisms that need something solid to attach to can only survive where nodules are present. Even a small increase in nodule cover has a disproportionate effect on biodiversity: when nodule coverage on the seafloor goes from about one percent to just three percent, the standing stock of both visible animals and giant single-celled organisms called xenophyophores roughly doubles.6PubMed Central. Ecology of a polymetallic nodule occurrence gradient: Implications for deep-sea mining
Below the visible fauna, the sediment itself teems with microbial life. Bacterial communities in CCZ sediments show high diversity, with multiple groups of bacteria involved in cycling metals, sulfur, and nitrogen through the deep-sea ecosystem.7PubMed. Bacterial diversity in the sediment from polymetallic nodule fields of the Clarion-Clipperton Fracture Zone And the biological story extends well above the seafloor: the water column over the CCZ supports mesopelagic predators like snipe eels and sawtooth eels, whose distribution and behavior are only now being documented with remotely operated vehicles.8Elem Sci Anth. Distribution, ecology, and behavior of midwater eels (Anguilliformes: Nemichthyidae and Serrivomeridae) from remotely operated vehicle surveys in the eastern Pacific Clarion-Clipperton Zone Mining at the seafloor could affect these midwater ecosystems through sediment plumes and noise that propagate upward through the water column.
Nodules as the Foundation of the Food Web
Removing nodules does not just take away metal-rich rocks; it collapses the ecological scaffolding that entire communities depend on. A food-web modeling study found that when nodules are removed from the system, the species lost are overwhelmingly those that depend on nodules as physical substrate, not as food. About 69 percent of species losses came from organisms that were obligately dependent on nodules for attachment, and the most devastated groups were bryozoans, which lost 81 percent of their species, followed by cnidarians like corals at 52 percent, and flatworms and sponges each losing half their species.9Scientific Reports. Polymetallic nodules are essential for food-web integrity of a prospective deep-seabed mining area in Pacific abyssal plains These losses then cascade: organisms that depend on the nodule-attached species for food or shelter disappear too, even if they have no direct relationship with the nodules themselves.
This cascading effect is what makes the CCZ’s ecology so fragile relative to the mining interest in it. The nodules are simultaneously the resource everyone wants and the keystone habitat feature everything lives on.
How Deep-Sea Mining Would Work
The basic concept behind nodule mining sounds deceptively simple: drive a large collector vehicle along the seafloor, pick up the nodules, and transport them to a surface vessel through a riser pipe. In practice, the engineering is formidable. One approach under development uses a Coandă-effect-based collector, which creates a high-velocity jet of water that follows a curved surface, generating suction strong enough to dislodge nodules from the sediment and funnel them into a collection duct. Some designs attempt to separate nodules from sediment near the seafloor so that less unwanted material gets pumped to the surface.10Results in Engineering. Mining of deep-seabed nodules using a Coandă-effect-based collector
Keeping sediment disturbance to a minimum is a stated engineering goal, but any collector that moves across the seafloor and vacuums up objects will stir up enormous quantities of fine abyssal sediment. That sediment forms plumes that drift with the current. How far those plumes travel is still an active area of research. Measurements from a deep-sea mining test on cobalt-rich crusts found that benthic plumes were limited to within about 1.4 kilometers of the mining site, with deposition dropping off within 100 meters of the disturbance.11PubMed Central. Measurement and modelling of deep sea sediment plumes and implications for deep sea mining But that particular study was conducted at a seamount, where rotational currents from internal tides helped contain the plume. Conditions on the flat abyssal plains of the CCZ may allow plumes to travel farther.
Noise is another concern that gets less attention than sediment. Mining machinery operating on the seafloor would generate continuous noise across multiple depth zones. Many marine animals in and above the CCZ use sound for communication, navigation, and detecting predators. A recent review found that noise sensitivity is widespread across taxa in the CCZ but that only about 35 percent of the taxonomic classes known to live there have been studied for noise impacts at all.12PubMed. Noise from deep-sea mining in the Clarion-Clipperton Zone, Pacific Ocean will impact a broad range of marine taxa Fish that rely on acoustic communication are thought to be especially vulnerable, and chronic noise exposure could disrupt behavior and physiology in ways that ripple through the food web.
Recovery Takes Decades, If It Happens at All
One of the most important questions about deep-sea mining is how long it takes the ecosystem to bounce back. The evidence so far is sobering. A test mining experiment conducted decades ago in a nodule field in the Peru Basin left tracks on the seafloor that are still visible and biologically impaired after more than 40 years. A 2025 study of that site found that biological impacts persisted across many groups of organisms, although some populations, including sediment-dwelling macrofauna and certain large sessile animals, had begun to re-establish.13Nature. Long-term impact and biological recovery in a deep-sea mining track The researchers concluded that mining impacts in the abyssal ocean will persist for at least decades and that communities in directly disturbed areas will remain altered even where some recolonization occurs.
The picture at finer biological scales is even more discouraging. Twenty-six years after a simulated mining disturbance in the same Peru Basin test area, faunal carbon stock inside the plough tracks was still only about 54 percent of the stock in undisturbed sediment nearby.14Biogeosciences. Abyssal plain faunal carbon flows remain depressed 26 years after a simulated deep-sea mining disturbance And microbial activity, the engine that drives nutrient recycling in deep-sea sediments, was reduced by up to fourfold in the most affected spots. Microbial cell counts were roughly halved in freshly disturbed tracks, and growth estimates suggested that microbially mediated functions would need over 50 years to return to baseline levels.15PubMed Central. Effects of a deep-sea mining experiment on seafloor microbial communities and functions after 26 years
These timescales matter because the nodules themselves grow at millimeters per million years. If you remove them, the hard substrate that the ecosystem relies on is not coming back within any meaningful human timeframe. Recovery of soft-bodied organisms in the sediment is at least conceivable over decades; recovery of the nodule-dependent community structure is essentially impossible within the scope of human planning.
Who Governs the Deep Seafloor
The CCZ lies beyond any nation’s jurisdiction, in waters classified under international law as “the Area.” Under the United Nations Convention on the Law of the Sea (UNCLOS), mineral resources on the deep seabed beyond national boundaries are considered the “common heritage of mankind,” meaning no single country owns them. To manage this common heritage, UNCLOS created the International Seabed Authority (ISA), which has been operating since 1996 and now has 167-plus member states and the European Union.16Marine Policy. The current status of deep-sea mining governance at the International Seabed Authority
The ISA’s dual mandate creates an inherent tension. It is charged with both organizing and controlling mineral extraction for the benefit of humankind and ensuring effective protection of the marine environment from harmful effects.16Marine Policy. The current status of deep-sea mining governance at the International Seabed Authority In practice, the ISA has issued exploration contracts to various state-sponsored entities, allowing them to survey large claim areas in the CCZ. But the regulations that would govern actual commercial exploitation, the “Mining Code,” have been under negotiation for years and remain unfinished. Some ISA members are pushing for rapid exploitation while others are calling for a moratorium.17npj Ocean Sustainability. The struggle at the International Seabed Authority over deep sea mineral resources
UNCLOS also requires that any economic benefits from deep-seabed mining be equitably distributed, with particular consideration for developing states. State sponsorship is required for all non-state entities that apply for a license: a private mining company cannot operate in the Area without a sponsoring government.17npj Ocean Sustainability. The struggle at the International Seabed Authority over deep sea mineral resources This creates a geopolitical layer where sponsoring states sometimes hope for tangible economic benefits from the companies they back, blurring the line between guardian of the common heritage and interested party.
Protected Areas and Their Limits
In 2012, the ISA established nine no-mining zones within the CCZ called Areas of Particular Environmental Interest (APEIs). These were designed as a representative network of protected areas meant to safeguard biodiversity and ecosystem function from mining impacts.18Frontiers in Marine Science. Patterns of Macrofaunal Biodiversity Across the Clarion-Clipperton Zone: An Area Targeted for Seabed Mining The idea is sound in principle: set aside reference areas that capture the range of habitats in the CCZ so that scientists can monitor what mining does and nature retains refugia from which recovery might eventually spread.
In practice, the APEIs have significant gaps. Biodiversity within them has been barely sampled. As of one major assessment, a total of nine box cores had been collected across just three of the nine APEIs.18Frontiers in Marine Science. Patterns of Macrofaunal Biodiversity Across the Clarion-Clipperton Zone: An Area Targeted for Seabed Mining That is an absurdly thin evidence base for areas meant to represent millions of square kilometers of diverse seafloor. Scientists do not yet know with confidence whether the APEIs truly capture the biological variation present across the CCZ, which means they may not function as the ecological safety net they were intended to be.
The Geopolitics of Proprietary Data
An underappreciated dimension of the CCZ debate is who controls the information. Exploration contractors have accumulated vast datasets on seafloor geology, biology, and nodule distribution across their claim areas. Much of that data is proprietary, collected at private expense and held as commercial secrets. This creates an information asymmetry: the entities arguing for mining often have far better data on what is at stake than the regulators, scientists, and civil society groups trying to evaluate the risks. The power that certain states and firms hold in shaping the ISA’s exploitation regime arises in part from this contested position around proprietary data and the political economy of financing deep-sea ventures.19International Social Science Journal. Mining the seabed, enclosing the Area: ocean grabbing, proprietary knowledge and the geopolitics of the extractive frontier beyond national jurisdiction
This dynamic complicates the ISA’s ability to fulfill its mandate. If regulators cannot independently verify environmental baselines, set meaningful thresholds for acceptable harm, or assess whether APEIs actually match the biodiversity in contract areas, governance becomes partly performative. Several researchers have argued that transparent data sharing should be a prerequisite for any exploitation license, but the current framework does not fully enforce that.
What Happens to the Sediment Chemistry
Beyond the visible organisms, mining disturbance reshapes the chemistry of the seafloor in ways that affect everything from nutrient cycling to the deep ocean’s role in the carbon cycle. When collector vehicles scrape away the top layer of sediment, they remove the most biologically active material: the reactive, carbon-rich organic matter that fuels microbial life. Modeling of CCZ contract areas has shown that removing this surface layer causes oxygen consumption rates in the sediment to drop sharply, allowing oxygen to penetrate up to ten times deeper into the remaining sediment. This in turn shuts down denitrification and manganese reduction, processes that drive nutrient availability for the broader ecosystem.20Biogeosciences. Impact of small-scale disturbances on geochemical conditions, biogeochemical processes and element fluxes in surface sediments of the eastern Clarion–Clipperton Zone, Pacific Ocean
The deep-sea sediment acts as a slow-motion carbon sink, locking away organic material that sinks from the productive surface waters above. When that surface sediment is stripped away or mixed by mining equipment, the accumulated carbon budget gets disrupted. In a world increasingly focused on natural carbon sequestration, the possibility that deep-sea mining could compromise one of the planet’s long-term carbon storage systems adds another dimension to the cost-benefit analysis.
Bioprospecting and Genetic Resources
Minerals are not the only valuable resource in the CCZ. The extreme conditions of the deep sea have driven evolution in unusual directions, producing organisms with biochemistry that has no equivalent on land. Compounds from deep-sea microbes and other marine life have potential commercial value in the pharmaceutical and biotechnology industries, a pursuit often called bioprospecting.21Priviet Social Sciences Journal. Addressing biopiracy through the BBNJ agreement’s marine genetic resources framework: Reflections from the clarion-clipperton zone for Indonesia’s future Enzymes that function under extreme pressure, proteins stable at near-freezing temperatures, and novel antimicrobial compounds are all plausible outputs from deep-sea organisms that have had millions of years to evolve specialized chemistry.
The legal framework around marine genetic resources beyond national jurisdiction is still being built. The 2023 High Seas Treaty (formally the BBNJ Agreement) is meant to address access to and benefit-sharing from these resources, but ratification and implementation are ongoing processes. The concern is that if mining destroys habitats before their biological inhabitants are even cataloged, the genetic resources vanish before anyone knows what was lost. Given that new species are being described from nearly every CCZ expedition, the scope of what remains undiscovered is hard to overstate.