DISTURBANCE IN THE DEEP

With land resources rapidly depleting, eyes are turning to the seabed as a whole new source of metals. But at what cost to marine wildlife?

- Helen Scales

Giant, electric mining machines, thundering across the deep seabed miles under water, may seem the stuff of science fiction – like the idea of mining asteroids, or the moon – but they could soon become a reality. Plans paving the way towards the first deep-sea mines were delayed by the pandemic but are likely to move ahead in 2021. If they do, this could give the green light to a brand-new way for humans to exploit the planet’s resources.

Interest in deep-sea mining began in the late 1960s, when corporations explored the possibilities of gathering metal-rich rocks scattered across abyssal plains. Resembling lumps of coal, these nodules take millions of years to form as dissolved minerals in seawater settle onto a hard nucleus, such as a fragment of ancient shark tooth or whale ear bone. The mix of metals usually includes about one-third manganese, plus smaller amounts of cobalt, nickel and rare-earth metals. Several tonnes of nodules were brought up in the 1970s, demonstrating that the industry was technically possible. Nevertheless, following a crash in global commodity prices, the first wave of deep-sea mining didn’t take off.