Deep-sea mining (DSM) has sparked major concern among environmentalists and scientists due to its potential impact on fragile ecosystems. As mining operations target the ocean's depths for valuable mineral resources, the risk of endangering rare and unknown species grows. This raises critical questions about the balance between resource extraction and preserving biodiversity in these largely unexplored habitats.1-3
Polymetallic nodules with shark tooth from a depth of 5000 m in the Pacific Ocean.Image Credit: V.Gordeev/Shutterstock.com
What is Deep-Sea Mining?
DSM is a proposed commercial industry that involves extracting mineral deposits from the seabed at depths greater than 200 meters. The deep seabed covers about two-thirds of the ocean floor. The process includes prospecting, exploration, and refining of ores, typically done on land.1-3
There are three main types of deep-sea mineral deposits: polymetallic nodules found at depths of 3 to 6.5 km and containing cobalt, nickel, copper, manganese, and rare earth elements (REE); polymetallic sulfides near hydrothermal vents at 1 to 4 km and containing copper, lead, zinc, gold, and silver; and cobalt-rich ferromanganese crusts at depths between 400 m to 3.5 km and containing nickel, REE, copper, and cobalt.1-3
Polymetallic nodules are collected by mining vehicles that scrape the seabed's surface along with the top layers of sediment. The extracted materials are then piped to a surface vessel for processing, while wastes like sediments and organic materials are pumped back into the water.1-3
Why is Deep-Sea Mining Carried Out?
As demand for critical minerals like cobalt, lithium, and graphite surges to support low-carbon technologies like electric vehicle batteries, solar panels, and wind turbines, the mining industry and governments are looking to exploit the seafloor for its vast mineral resources. DSM can meet the growing demand for these materials while reducing the environmental and social impacts of land-based mining.1-3
Deep-seabed ores, particularly polymetallic nodules, contain higher concentrations of minerals and may require less technological innovation to extract. DSM also has a lower environmental and health impact compared to traditional mining under specific scenarios, although these claims remain unverified by scientific evidence.1-3
Environmental Problems with Deep-Sea Mining
DSM poses significant environmental risks, threatening marine biodiversity and ecosystems. Despite efforts to protect deep-sea habitats, the full impact of DSM on the environment remains unknown. While rising demand for metals may drive DSM, it could devastate habitats and cause species loss.4
Mining operations affect both the deep sea and the broader ocean ecosystem. Mining equipment is loud, disruptive to the ocean floor and surface, and causes light pollution. It also stirs up sediments that displace animals and creates dust clouds that harm filter-feeders dependent on clean water. The disruption endangers fish stocks, impacting communities in the global south that rely on these resources for food and income.4
Click here to save this article for later
DSM may release carbon stored in the sea into the atmosphere. Beyond biological effects, the chemical composition of the deep sea is altered as toxic metals are released during manganese extraction. Vertical metal extraction also brings up deep-sea water, which is discharged at the top of the ocean or along the way, potentially disrupting surface ecosystems due to differences in water composition.4
Rare and Unidentified Species in the Ocean
Many deep-sea regions, particularly the cold, lightless Pacific Ocean, are being explored for mining opportunities, but much of their biodiversity remains unknown. Researchers have reviewed existing records and estimate that 6,000-8,000 new species could be discovered in one of these regions. This number is likely an underestimate as many rare and strange creatures continue to be uncovered, highlighting the vast unexplored diversity of the deep sea.5,6
The Clarion-Clipperton Zone (CCZ) is a vast area of the Pacific Ocean located between Hawaii and Mexico and known for its deep-sea abyssal plain. Despite its seemingly barren appearance, the CCZ is rich in valuable mineral nodules, prompting interest from the mining industry. What was once thought of as an unremarkable underwater wasteland is now recognized for its surprising biodiversity.5,6
The region hosts a variety of life, including floating sponges tethered to the rocks, tiny hairy worms in the muddy sediment, starfish, and crustaceans, all thriving in the cold, dark depths. Species like the "gummy squirrel" sea cucumber and ghostly white sea anemones are part of this unique ecosystem.
The diversity of life in the CCZ is a result of its ancient, stable environment, which has allowed species to evolve and diversify over millions of years.5,6
Over recent decades, surveys by scientific organizations, mining contractors, and governments have explored the CCZ in the Pacific Ocean and uncovered thousands of specimens. However, many of these remain unidentified, with 438 known species and over 5,000 unnamed species. Researchers predict that an additional 6,000 to 8,000 species may still be undiscovered in this region.5,6
Scientists have used various methods, including sediment collection and remote vehicles, to gather data from the seafloor. While some areas may seem sparse, they often contain rare species, particularly in the mud. The nodules found on the seafloor serve as a unique habitat, akin to miniature coral gardens.5,6
Deep-Sea Mining’s Impact on Rare Species
The region's biodiversity is Earth's most precious and least understood; thus, deep-sea mining could lead to species extinction before they are formally identified.
Hundreds of rare species in the CCZ face habitat destruction from DSM. While the area is rich in minerals, the thriving ecosystem adds a complex layer of consideration to potential mining efforts, raising concerns about environmental impacts.5,6
A new study has led to 184 deep-sea species being added to the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, mainly due to deep-sea mining. The IUCN Red List tracks species at risk of extinction. The research focused on mollusc species from hydrothermal vents, a habitat under imminent threat from DSM.7,8
Out of the 184 assessed species, 62% were listed as threatened. Of these, 39 species are critically endangered, 32 are endangered, and 43 are vulnerable. In comparison, 25 species fully protected from mining are listed as least concern, while 45 species are near threatened, with some populations facing mining threats and others within protected areas.7,8
The Future of Deep-Sea Mining and Marine Protection
To protect biodiversity, it is essential to understand the biological communities in areas designated for resource development, which helps implement effective impact mitigation and ensures minimal harm to the marine environment. However, some experts argue that DSM inevitably damages habitats due to its irreversible impacts. There are also concerns about the narrative that DSM is essential for the green revolution, with some suggesting that alternative approaches, such as mineral recycling and development of new battery technologies, may reduce the need for these metals.1-8
For instance, the growing shift from nickel manganese cobalt oxides batteries toward lithium iron phosphate (LFP) batteries can reduce reliance on deep-sea mineral deposits as the key materials of LFP batteries, iron and lithium, are not DSM targets. Similarly, emerging technologies like sodium-ion batteries may replace lithium and cobalt, offering cheaper and more abundant alternatives.1
References and Further Reading
- Wang, K., Barbanell. M., Baines, J., Ashford, O. (2024) What We Know About Deep-Sea Mining — and What We Don’t [Online] Available at https://www.wri.org/insights/deep-sea-mining-explained (Accessed on 25 March 2025)
- Deep-Sea Mining [Online] Available at https://wedocs.unep.org/bitstream/handle/20.500.11822/45494/deep_sea_mining.pdf?sequence=3&isAllowed=y (Accessed on 25 March 2025)
- Deep-sea mining [Online] Available at https://iucn.org/resources/issues-brief/deep-sea-mining (Accessed on 25 March 2025)
- Petrossian, G. A., Lettieri, J. (2024). A precautionary tale: Exploring the risks of deep-sea mining. Marine Policy, 162, 106073. DOI: 10.1016/j.marpol.2024.106073, https://www.sciencedirect.com/science/article/abs/pii/S0308597X2400071X
- Pacific deep-sea mining interests reveal rare species, and a scramble to name them [Online] Available at https://www.france24.com/en/live-news/20250317-race-to-name-creatures-of-the-deep-as-mining-interest-grows (Accessed on 25 March 2025)
- Davis, J. (2023). Around 90% of species in proposed deep-sea mining zone are unnamed [Online] Available at https://www.nhm.ac.uk/discover/news/2023/may/90-of-species-in-prospective-deep-sea-mining-zone-are-unnamed.html (Accessed on 25 March 2025)
- Over 180 deep-sea species added to 'red list' [Online] Available at https://oceanographicmagazine.com/news/deep-sea-species-iucn-red-list/ (Accessed on 25 March 2025)
- Thomas, E. A., Molloy, A., Hanson, N. B., Böhm, M., Seddon, M., & Sigwart, J. D. (2021). A Global Red List for Hydrothermal Vent Molluscs. Frontiers in Marine Science, 8, 713022. DOI: 10.3389/fmars.2021.713022, https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2021.713022/full
Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.