Deep-Sea Mining: Ecological and Mineral Assets

10/16/20233 min read

swimming jellyfish
swimming jellyfish

Deep-sea (or deep seabed) mining has attracted public attention due to its implications for marine life.

The deep seabed refers to the seabed at ocean depths exceeding 200m, spanning about two-thirds of the world's seafloor, and is home not only to vast mineral deposits but also some of our planet's least understood species and ecosystems (IUCN 2022).

This year, an incident involving Canadian corporation The Metals Company (‘TMC’) concerned a video depicting what appeared to be discharge of sediment plumes and/or wastewater at the ocean surface by a TMC vessel (The Guardian 2023). Deep-sea mining could potentially have adverse and long-term (if not permanent) impacts on the marine environment by - (a) disturbing the seafloor through excavation, (b) endangering marine health and survival through the generation of sediment plumes, and (c) generally polluting the sea through noise, vibration, light, and vessel leakages and spills (IUCN 2022).

Specifically with reference to example (b) (sediment plumes), an estimated 40,000MT of sediment disturbance can be expected for every 10,000MT of deep-sea mineral nodules mined per day, likely resulting in plumes which persist in suspension and spread laterally in accordance with currents (Sharma 2015). The presence of such sediments could reduce visibility, impeding photosynthesis, net primary production, and ultimately ecological productivity across trophic levels (Sharma 2015), and also obstruct respiration, communication, and feeding activities of various marine species (IUCN 2022).

The TMC incident appears to have faded from the spotlight after the company’s statement that the discharge constituted an “overflow of seawater mixed with a small amount of sediment and nodule fragments, which contain no toxic levels of heavy elements” (TMC 2023).

However, the question of deep-sea exploitation is far from resolved both commercially and legally.

As the world shifts away from fossil fuels toward alternative and renewable energy and new technologies, the demand for critical minerals – such as the polymetallic sulphide deposits, ferromanganese crusts, and polymetallic nodules contained within the ocean floor – is higher than before (A&O 2023). Proponents claim that deep-sea mining would be less invasive than existing terrestrial mining activities and could in fact reduce reliance on the latter (CNBC 2023a, CNBC 2023b). Scientists highlight that these minerals often also function as habitats and communities for unique and biologically diverse organisms, many of which remain unstudied (Scientific American 2023).

Despite the declaration of a conditional moratorium on deep-sea mining in 2021 by IUCN members, it would appear that the ISA has, as of May 2022, issued more than 30 deep-sea exploration contracts (IUCN 2022). In July 2023, the ISA indicated that its regulations on deep-sea exploitation would not be finalized until 2025, and that no extraction/exploitation would be authorised in the meantime (Scientific American 2023). Although the ongoing exploration contracts do not permit exploitation per se, it has also been observed that there could be a lack of clarity in the ISA’s monitoring and enforcement regime in the event that a party commences exploitation operations prior to the finalization of ISA regulations on deep-sea exploitation (A&O 2023). It is now uncertain whether the ISA is obliged to provisionally approve mining applications, even in the absence of regulations governing such activities (CNBC 2023a).

While each country has jurisdiction over its own seabed, the remaining area is regulated by the International Seabed Authority (the 'Area'), and the United Nations Convention on the Law of the Sea ('UNCLOS') stipulates that the Area and the resources contained therein are mankind's common heritage (IUCN 2022). It is therefore arguable that the ecosystems as well as minerals contained within the Area ought to be protected and used for the benefit of all of mankind.

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