Charlotte Jarvis, The Ocean Foundation
ACUA Associate Board Member

Deep sea mining (DSM) has been in and out of the news over the last few years, especially after the United States’ executive order and The Metals Company submitting a deep sea mining application for the international seabed. However, DSM poses risks to the marine environment which have not been fully studied, and the process may destroy unknown underwater cultural heritage (UCH), most of which remains unrecorded.

DSM is a potential commercial industry that seeks to mine mineral deposits from the ocean floor in the hopes to extract minerals, such as manganese, copper, cobalt, and nickel. The main areas of mineral deposits that commercial mining is focused on are located on the abyssal plains (for nodules), hydrothermal vents (for sulphides), and seamounts (for crusts). The mining has the potential to cause major disturbances to the marine environment, including direct damage to the benthic fauna, habitat destruction, pollution from sediment plumes and wastewater discharge, and non-stop noise and light pollution across the water column. The impacts of DSM could encompass both destruction of physical objects on the seafloor as well as damages to cultural practices and connections to the ocean.

At the time of writing, commercial DSM in international waters has not begun, and there are still many unknowns as to how commercial scale mining could proceed. Mining nodules would require a machine, some companies’ technology resembles a three-story-tall tractor, which is taken to the seafloor to take up the top layer of sediment containing the nodules with the targeted minerals; this process would also recover any other items on the seafloor such as rocks, flora, and small fauna. These materials are transported up to a surface vessel where the slurry is processed and unneeded material is returned to the water via a discharge plume. The impacts of this method have been likened to strip mining. Another company has proposed a technology which would use artificial intelligence (AI) to pluck each nodule individually from the seafloor and posit this method as being less damaging to the seafloor habitats, despite the nodules themselves being critical habitats.

A field of manganese nodules. (Source: NOAA Office of Ocean Exploration and Research)

DSM recently was in the global spotlight during the July meetings of the International Seabed Authority (ISA). These meetings were part II or the 30th Session of the ISA and included the Council Meeting and the ISA Assembly meeting. The ISA is the international body tasked with overseeing and mining activities in The Area, the seabed that lies outside of National Jurisdiction (for further information see here). The United Nations Convention on the Law of the Sea (UNCLOS, 1982) gives the ISA the responsibility to ensure that any mining activities in the Area, legally classified at the common heritage of humankind, are only permitted if for the benefit of humanity as a whole and future generations (UNCLOS Articles 140 and 145).

Crucially, the ISA Council meeting ahead of the recent ISA Assembly did not finalise the Mining Code and mandated an inquiry into the potential breach of agreements and international law with The Metal Company’s attempts to bypass the ISA and mine in international waters. These meetings wrapped up without any concrete action towards a moratorium on DSM, which is especially frustrating just weeks after various governments making bold promises to protect the ocean at the UN Ocean Conference in Nice (June 2025). Currently, 38 countries have statements opposing DSM and they are joined by hundreds of scientists, international organizations, companies, and finance organizations (see DSCC page for more).

While there has been an avalanche of research and voices speaking out about the impacts DSM may have on the marine environment and natural heritage, less attention has been paid to the potential cultural heritage impacts. The tangible remains of UCH are not only relevant to human history, but are integral to natural heritage, and there exists a multitude of UCH on the seafloor, even in deep waters. It is not a barren landscape, void of heritage. The stories of our societies and our ancestors are wrapped in intangible connections with the ocean and preserved on the seafloor as artifacts, shipwrecks, and remains of those lost or buried at sea. Shipwrecks also act as vital parts of the seabed environment, functioning as artificial reefs, safe havens for juvenile fish species, or hard biologically-productive substrates on otherwise bare seafloors.

Map of the elements for proposed mining as well as the zones in which the ISA has issued contracts. The Clarion Clipperton Zone, left side of the map, has been the most sought-after with 17 contracts issued for that area alone. (Source: Created by Jarvis, 2024. Based on information from the International Seabed Authority)

The deep sea is often referred to as earth’s final frontier, yet its inaccessibility means it receives relatively less attention than other ocean areas. Despite this, the deep sea has been vital to humans long before scientists entered the picture. Many cultural groups around the globe have creation stories linked to the ocean, and especially the deep ocean. The deep sea has also had long-held significance in cultures globally as providing habitats for marine species, such as whales, sharks, or turtles, which hold deep cultural importance. Thanks to technology, the deep sea has been reachable by archaeologists for decades. Tools such as Remotely Operated Vehicles (ROVs) and Autonomous Underwater Vehicles (AUVs) have aided in the search, survey, identification, and even excavation of UCH sites.

Recognition of the potential devastation of UCH by DSM practices lags far behind the research conducted on natural heritage and this must be addressed before any action towards DSM can be taken. The impacts of DSM could encompass both destruction of the natural environment, physical objects on the seafloor, as well as damage to cultural practices and connections to the ocean (see 2022 NOAA Ocean Exploration report). In the Pacific especially, DSM is related to the island environment because ‘the ocean is at the heart of one’s identity’ and ‘integral to the core identity of Islanders’. Other important elements of UCH in the Pacific include canoe navigation and wayfinding practices, which are integral to cultural identity in Oceania. Tangible evidence of this is rare, but includes spiritual associations with natural heritage, such as shark calling. Additionally, vessels and shipwrecks represent important artifacts of human history and are the final resting place for many that have sunk in the open water areas of the high seas, including those from both World Wars and the global slave trading.

Humans have a long history of detrimental activities in the ocean, but the deep sea represents ‘one area where it is not too late and where we have a chance to get it right’. This point holds especially true when archaeologists consider the impacts of bottom trawling on their sites and the notable destruction this unregulated practice has caused (see Jarvis, 2024). With DSM, there is an opportunity to intervene before operations start. This was not successfully done with trawling and countless pieces of history have been lost. These mistakes cannot be repeated with DSM.

The Ocean Foundation, has an upcoming Open Access book on the subject (Threats to Our Ocean Heritage: Deep Sea Mining) coming out in August/September 2025 for more information. ACUA Board Member Charlotte Jarvis is the editor.

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