What is deep-sea mining?

Recent efforts to find new sources of minerals have led some countries and private companies to turn their attention to the deep seabed.

There are a variety of minerals in the deep sea that are being targeted across a range of underwater habitats. In the abyssal plains at depths of 3500-6000 meters, there are polymetallic nodules that contain manganese, nickel, cobalt and copper. Hydrothermal vents, or polymetallic sulfides, are at depths of 1000-4000m and contain metals such as copper, gold, silver and zinc. Lastly, seamounts can often be covered in cobalt-rich ferromanganese crusts and are found at depths between 800 and 2500m. Minerals such as cobalt, nickel, manganese, copper, and rare earth elements (molybdenum, yttrium, tellurium) can be found in these crusts. 

The metals being currently targeted most are cobalt, nickel, and manganese, which are used for battery chemistries in applications such as electric vehicles. However, battery technology has evolved in recent years with cheaper, more available metals such as iron and phosphate replacing rarer metals like cobalt and nickel. 

Technology capable of extracting metal resources in these extreme and challenging environments is only in development and has not been tested at commercial scale.

What is the current state of deep-sea mining?

Deep-sea mining is still in its infancy but exploration licences, covering 1.5 million square kilometers in the Pacific, Atlantic and Indian Oceans, have already been granted by the International Seabed Authority (ISA). As a result, exploration activities have been taking place in international waters. Importantly, no exploitation licenses that would permit commercial deep-sea mining have been granted. 

Additionally, several countries are exploring mineral resources within their Exclusive Economic Zones (EEZs) and Extended Continental Shelves (ECSs), although none have begun commercial mining operations.

What is the International Seabed Authority?

The International Seabed Authority (ISA) is an organization created by the United Nations to manage all mineral-related activities in areas beyond national jurisdiction, while ensuring the effective protection of the marine environment from harmful effects that may arise from these activities. 

The international seabed and its resources are the “common heritage of mankind” and should benefit humankind as a whole. This creates complex governance and regulatory challenges, including for benefit-sharing given the recent market downturns for targeted minerals such as cobalt and nickel. This is further compounded by significant environmental and socio-economic risks, including to the productivity and quality of economically-important fisheries, to sources of marine genetic resources, to underwater cultural heritage, and to slow-to-recover deep-sea ecosystems.

How can Deep-Sea Mining Watch be used?

There are a range of uses for DSMW that include, but are not limited to, monitoring current mineral-related activities, understanding past activities, as well as investigating how deep-sea mining overlaps with other marine industries such as fisheries. 

Within the workspace, users have the ability to zoom in or out temporally and spatially. So, users can understand trends in human activity within leasing areas, as well as explore individual vessels, including current and historic vessel activity.

What are the vessels in the Deep-sea Mining Vessel Group, and how were they selected?

The vessels within the Deep-sea Mining Vessel Group of DSMW were individually identified as those that have participated or are participating in mineral-related activities. This includes, but is not limited to, deep-sea mineral prospecting, environmental baseline studies and/or the testing of mining equipment. These vessels are not necessarily exclusively mining vessels; many may conduct other activities unrelated to deep-sea mining (e.g., research, seismic monitoring). 

We do not assert that all activity from these vessels are related to deep-sea mining. However, when spatially overlaid with ISA license areas, areas of mineral interest in domestic EEZs or on ECSs, and filtered by timeframe, DSMW can help identify when they may have participated in deep-sea mineral-related activities.

What are the main environmental concerns associated with deep-sea mining?

Direct impacts to deep-sea biodiversity

The deep sea hosts some of the most unique biodiversity on the planet, including 4,000-year-old corals and ghost-like octopuses. Deep-sea species are particularly vulnerable to change given the immense timescales over which their ecosystems form, as well as the stabilities of these ecosystems. Further, many of the species associated with the three ecosystems currently targeted for deep-sea mining are reliant on the mineral-rich substrates as attachment surfaces. Exploitation of these resources and associated habitat destruction will cause significant impacts to associated communities as well as ecosystem functioning, with recovery occurring only on decadal to million-year timeframes. 

Sediment plumes

Mining will disrupt the seabed, resulting in plumes that could travel tens to hundreds of kilometers. The plumes generated on the seafloor could smother local and adjacent communities. Discharge plumes produced in the water column, including at the sea surface or mesopelagic depths, may also impact broader marine ecosystems, including fisheries that are critical to global food security. 

Sediment plumes from mining are likely to contain significantly elevated levels of toxic metals, which could present a contamination risk for seafood supplies and other biodiversity. 

Noise and light pollution

Deep-sea mining operations will generate significant amounts of noise and light pollution, both at the sea surface and at depth. Deeper ecosystems are adapted to darkness and may be significantly impacted by introduced light. Noise is also known to affect marine life, from cetaceans and other marine mammals to smaller plankton. 

Long-term carbon storage

The ocean is the planet's largest carbon sink, and the deep seabed is the main storehouse of sequestered carbon. While additional research is needed, impacts in the water column from the discharge plume could impact the biological carbon pump that removes carbon from the atmosphere and stores it deep in the ocean on substantial timescales. Additionally, deep-sea mining may disrupt carbon sequestered in deep sediments.

Additional Resources

Amon, D. J., Gollner, S., Morato, T., Smith, C. R., Chen, C., Christiansen, S., ... & Pickens, C. (2022). Assessment of scientific gaps related to the effective environmental management of deep-seabed mining. Marine Policy, 138, 105006. https://doi.org/10.1016/j.marpol.2022.105006

Dowd, M. H., Assad, V. E., Cazares-Nuesser, A. E., Drazen, J. C., Goetze, E., White, A. E., & Popp, B. N. (2025). Deep-sea mining discharge can disrupt midwater food webs. Nature Communications, 16(1), 9575. https://doi.org/10.1038/s41467-025-65411-w

Drazen, J. C., Smith, C. R., Gjerde, K. M., Haddock, S. H., Carter, G. S., Choy, C. A., ... & Yamamoto, H. (2020). Midwater ecosystems must be considered when evaluating environmental risks of deep-sea mining. Proceedings of the National Academy of Sciences, 117(30), 17455-17460. https://doi.org/10.1073/pnas.2011914117

Levin, L. A., Amon, D. J., & Lily, H. (2020). Challenges to the sustainability of deep-seabed mining. Nature Sustainability, 3(10), 784-7. https://doi.org/10.1038/s41893-020-0558-x

Niner, H. J., Ardron, J. A., Escobar, E. G., Gianni, M., Jaeckel, A., Jones, D. O., ... & Gjerde, K. M. (2018). Deep-sea mining with no net loss of biodiversity—an impossible aim. Frontiers in Marine Science, 5, 53. https://doi.org/10.3389/fmars.2018.00053

Rabone, M., Wiethase, J. H., Simon-Lledó, E., Emery, A. M., Jones, D. O., Dahlgren, T. G., ... & Glover, A. G. (2023). How many metazoan species live in the world’s largest mineral exploration region?. Current biology, 33(12), 2383-2396. https://doi.org/10.1016/j.cub.2023.04.052

Simon-Lledó, E., Bett, B. J., Huvenne, V. A., Köser, K., Schoening, T., Greinert, J., & Jones, D. O. (2019). Biological effects 26 years after simulated deep-sea mining. Scientific reports, 9(1), 8040. https://doi.org/10.1038/s41598-019-44492-w