Scientists and policymakers are now faced with a difficult question: should the pursuit of greener energy come at the cost of deep-sea ecosystems?

The polymetallic nodules were found four kilometres beneath the ocean surface, and contain manganese, nickel and cobalt, essential for electric vehicle batteries and green technologies.

Now, plans are afoot to begin trial collection of the manganese nodules, or mineral concretions, from the Pacific Ocean site as early as 2025 with a view toward commercialization. Manganese ...