As rising demand for minerals and metals sparks a new interest in seabed mining, a study has warned that extracting these materials from the ocean floor could permanently damage ecosystems.

The first commercial seabed mining venture — which will target sulphides at depths of over 1.5km off Papua New Guinea — is scheduled to start early next year. However, researchers from the University of Exeter and Greenpeace have found that such activities are likely to have “long-lasting and unforeseen consequences” for marine life.

The study is the first to examine the potential impacts of seabed mining operations, including habitat destruction and the creation of large underwater sediment plumes, as well as the effects of chemical, noise and light pollution.   

Seabed mining would typically involve the extraction of minerals over wide areas of the sea floor, rather than digging to significant depths. Some operations are already underway at shallower depths near national coastlines.

"Our knowledge of these ecosystems is still limited, but we know they're very sensitive," says Dr David Santillo, a marine biologist and Greenpeace scientist based at the University of Exeter. "Recovery from man-made disturbance could take decades, centuries or even millennia, if these ecosystems recover at all."

According to the paper, published in the journal Frontiers in Marine Science, alternatives to seabed mining have already been devised. Proposals include substituting metals in short supply for more abundant minerals with similar properties, as well as more effective recycling of components from disused products.

"As governments prepare to set the rules and the first companies gear up to mine, now is the time to ask whether we just have to accept seabed mining, or should instead decide that the potential damage is just so great that we really need to find less destructive alternatives," says Santillo.