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deep sea mining

Researchers from the Massachusetts Institute of Technology (MIT) have begun unprecedented studies into the environmental effects of sediment plumes from deep-sea mining.

While deep-sea mining is a scarcely understood practice, it is known that around 4500 metres below the ocean’s surface, there are rocks known as “polymetallic nodules” rich in nickel and cobalt.

To “mine” these nodules, some proposals involve large underwater vehicles which are developed to collect the nodules along with all the sediment below.

The issue – which MIT researchers have performed scientific modelling on – is the environmental impact the redistribution of this sediment has on marine flora and fauna.

MIT professor of mechanical engineering Thomas Peacock commented on the study and the feasibility of deep-sea mining.

“There is a lot of speculation about (deep-sea-mining’s) environmental impact,” he said.

“Our study is the first of its kind on these midwater plumes, and can be a major contributor to international discussion and the development of regulations over the next two years.”

The modelling assessed how the sediment plumes interact with ocean currents, predicting size, concentration and evolution of the plumes under a range of conditions.

The researchers hoped the plumes would conglomerate and stick much faster than they did.

“There was speculation this sediment would form large aggregates in the plume that would settle relatively quickly to the deep ocean,” Peacock said.

“But we found the discharge is so turbulent that it breaks the sediment up into its finest constituent pieces, and thereafter it becomes dilute so quickly that the sediment then doesn’t have a chance to stick together.”

The research could now be used to inform future deep-sea mining regulations in regard to sediment discharge and concentration, as the practice becomes more common and understood.

Peacock said more than one simple study will be needed to fully understand the implications of deep-sea mining, and many faculties of research will need to be involved.

“At the heart of the environmental question surrounding deep-sea mining is the extent of sediment plumes,” Peacock said.

“It’s a multiscale problem, from micron-scale sediments, to turbulent flows, to ocean currents over thousands of kilometres.

“It’s a big jigsaw puzzle, and we are uniquely equipped to work on that problem and provide answers founded in science and data.”