Commercial deep sea mining will increase risk to blue whales, dolphins: Study

Sounds produced from mining operations can overlap with frequencies at which marine mammals communicate; can cause auditory masking and behaviour change

By Susan Chacko
Published: Monday 20 February 2023
Settlement of sediment plumes generated by deep sea mining vehicles could smother the marine species at the bottom of the ocean, the study warned. Photo: iStock
Settlement of sediment plumes generated by deep sea mining vehicles could smother the marine species at the bottom of the ocean, the study warned. Photo: iStock Settlement of sediment plumes generated by deep sea mining vehicles could smother the marine species at the bottom of the ocean, the study warned. Photo: iStock

Deep seabed mining operations could present serious risks to ocean ecosystems, with disturbance on any scale being long-lasting and irreversible. Commercial-scale operations of deep seabed mining in 2023 may come at the expense of cetaceans like whales, dolphins and porpoises, a study has found. 

Commercial-scale operations have the potential to damage the oceans in ways we do not fully understand and at the expense of species that have been the focus of conservation efforts for many years, said a preliminary evaluation published in journal Frontiers in Marine Science. Many cetaceans, like blue whales and several dolphin species, are endangered. 

Read more: Budget 2023-24: Deep Ocean Mission gets Rs 600 crore; funds to be spent on research vessel, identifying minerals

Deep-sea mining is the process of retrieving mineral deposits from the deep seabed — the ocean below 200 metres — and covers two-thirds of the total seafloor.

If allowed, commercial-scale mining is expected to operate 24 hours a day, causing noise pollution. The mining noise can overlap with the frequencies at which cetaceans communicate, which can cause auditory masking and behaviour change in marine mammals, the analysis said.

Settlement of sediment plumes generated by mining vehicles could smother the species at the bottom of the ocean, or benthic species, in the vicinity. Sediment discharged from processing vessels can also increase turbidity in the water column, the study said.

“Far-from-sight impacts on cetaceans could go largely unquantified and unnoticed, along with those on other pelagic predator species that rely on deep ocean areas, including sharks,” the evaluation said. 

There is growing interest in the mineral deposits of the seabed. This is mainly due to depleting terrestrial deposits of metals such as copper, nickel, aluminium, manganese, zinc, lithium and cobalt. Demand for these metals is also increasing to produce smartphones, wind turbines, solar panels and batteries.

Polymetallic nodules are a potential mineral resource for copper, nickel, cobalt, iron, manganese, and rare earth elements. These nodules are found in various deep ocean regions, including the deep Pacific and Indian Oceans.

The nodules are approximately potato-sized and sit on the sediment surface across abyssal plains in the Clarion-Clipperton Zone (CCZ), a region spanning 5,000 kilometres (3,100 miles) across the central Pacific Ocean at depths of 4,000 - 5,500 metres. 

The CCZ is a habitat for cetaceans, including baleen (mysticetes) and toothed whales (odontocetes). Up to 30 cetacean populations, including globally endangered species like blue whales, can be found in the CCZ, where 17 exploratory deep-sea mining licenses have been granted.

The International Seabed Authority (ISA), “mandated under the UN Convention on the Law of the Sea to organise, regulate and control all mineral-related activities in the international seabed area for the benefit of mankind as a whole” till May 2022, had issued 31 contracts to explore deep-sea mineral deposits.

More than 1.5 million square kilometres of the international seabed have been set aside for mineral exploration.

No commercial-scale deep seabed mining operations has occurred yet. The ISA has only issued exploration contracts but is developing regulations to govern the transition to exploitation.

Read more: Shallow-water mining not a ‘silver bullet’ to resolve growing global need for metals: Study

In November 2022, ISA held its 27th session for developing a plan to regulate and approve deep-sea mining operations. Regulations for commercial mining are expected to go into effect in July this year. Large-scale mining operations will most likely follow soon after.

The Pacific island nation of Nauru June 2021 notified ISA of their plans to start deep sea mining. The Republic of Nauru reported ISA of the intention of its sponsored entity, Nauru ocean resources inc. (NORI) will launch its plans in two years, invoking a two-year rule inserted as a part of the UN Convention on Law of the Seas (UNCLOS).

The “two-year rule” clause of the UNCLOS requires the ISA to put in place the governance infrastructure - the rules, regulations and procedures governing the contours of deep sea mining within two years (in this case, July 2023). In case of failure, the ISA must at least evaluate the mining proposal by the end of two years.

The 11th Annual Deep Sea Mining Summit 2023, May 3-4, 2023, is to be held in London, United Kingdom. The key topics on the agenda include the “economic landscape and growth for deep sea mining and technological developments associated with commercialising”.

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