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Σάββατο, 27 Ιουλίου 2019

Seabed Mining is coming — bringing mineral riches and fears of epic extinctions

Sources: Map: M. Hannigton et al. Nature Geosci. 10, 158–159 (2017); Data: J. R. Hein et al. Ore Geol. Rev. 51, 1–14 (2013)
In 1972, a young ecologist named Hjalmar Thiel ventured to a remote part of the Pacific Ocean known as the Clarion–Clipperton Zone (CCZ). The sea floor there boasts one of the world’s largest untapped collections of rare-earth elements. Some 4,000 metres below the ocean surface, the abyssal ooze of the CCZ holds trillions of polymetallic nodules — potato-sized deposits loaded with copper, nickel, manganese and other precious ores.
A ghostly sponge lives on a Pacific seamount, one of the environments targeted by contractors interested in mining the ocean floor.Credit: Zhang Jiansong/Xinhua/Alamy



Deep sea animals collected from abyssal ocean floor in Clarion-Clipperton Zone. Clockwise from top left: Sea cucumber known as the ‘gummy squirrel’ (Psychropotes longicauda), a sea urchin and two sea cucumbers.Credit: DeepCCZ Project
Thiel was interested in the region’s largely unstudied meiofauna — the tiny animals that live on and between the nodules. His travel companions — prospective miners — were more eager to harvest its riches. “We had a lot of fights,” he says. On another voyage, Thiel visited the Red Sea with would-be miners who were keen to extract potentially valuable ores from the region’s metal-rich muds. At one point, he cautioned them that if they went ahead with their plans and dumped their waste sediment at the sea surface, it could suffocate small swimmers such as plankton. “They were nearly ready to drown me,” Thiel recalls of his companions.

In a later confrontation, Thiel — who was at the University of Hamburg in Germany — questioned how industry planned to test the environmental impacts of sea-bed mining. He was curtly advised to do his own test. So he did, in 1989.
Manganese nodules cover the sea floor in the Clarion–Clipperton Zone.Credit: ROV KIEL 6000, GEOMAR (CC BY 4.0)

Thirty years on, the test that Thiel and a colleague devised is still the largest experiment ever on the potential impacts of commercial deep-sea mining. Called DISCOL, the simple trial involved raking the centre of a roughly 11-square-kilometre plot in the Pacific Ocean with an 8-metre-wide implement called a plough harrow. The simulated mining created a plume of disturbed sediment that rained down and buried most of the study area, smothering creatures on the sea floor. The test revealed that the impacts of sea-bed mining reached further than anyone had imagined, but it did not actually extract any rocks from the sea bed, which itself would have destroyed even more marine life.

There have been many attempts to advance DISCOL’s basic approach, but none has succeeded, mostly owing to technical and financial difficulties. The most recently planned mining trial, to test a robotic nodule harvester in the CCZ this April, was called off at the last minute because of a technical failure. The trial, planned by the Belgian contractor Global Sea Mineral Resources, would have given scientists a better grasp of the impacts of sea-bed mining by using a 25-tonne tractor to plough the ocean floor.

This was definitely a significant setback, because it was really the only opportunity to try to even start to see the interaction of these big, heavy machines with the marine environment,” says Kristina Gjerde, a high-seas policy adviser with the International Union for Conservation of Nature in Cambridge, Massachusetts.

Such has been the troubled trajectory of deep-sea mining ever since eager industrialists proved, nearly a half century ago, that it was technically feasible to extract rare metals and minerals from the ocean floor. Companies and nations have often promised that they would soon start pulling valuable ores from the depths, but commercial efforts have failed to take off for a variety of reasons — notably huge up-front costs, the historically low value of deep-sea ores and the lack of regulations, which have contributed to investors’ wariness. 

“The technology is available — it’s the financial and regulatory uncertainty that has held the industry back,” says Govinder Singh Chopra, founder of SeaTech in Singapore, a designer of deep-sea mining support vessels. Now, it seems this nascent industry’s time has come. A growing demand for batteries to power electric cars and to store wind and solar energy has driven up the cost of many rare-earth metals and bolstered the business case for sea-bed mining. What’s more, the industry’s long-awaited regulations — in the form of a mining code — are due to be finalized by 2020, putting in place a process whereby contractors can apply for 30-year licences to mine assigned ‘claim areas’ in parts of the international sea bed such as the CCZ. Already, miners are exploring the potential wealth of these claim areas, but no commercial extraction will begin until the regulations are in place. Investments in this industry are now growing.

 Last month, a start-up called DeepGreen in Vancouver, Canada, announced that it is raising US$150 million to begin exploring mineral wealth in part of the Pacific Ocean — a sign of growing confidence in the industry’s future. 

Both scientists and conservationists, however, are worried that the creation of regulations will encourage the industry to start mining long before there is enough information on how operators can avoid causing serious environmental harm. The scarce data that exist suggest that deep-sea mining will have devastating, and potentially irreversible, impacts on marine life.

See more in the Nature Research Journal, 
Seabed mining is coming — bringing mineral riches and fears of epic extinctions,  by Olive Heffernan