A study published today in Current Biology is the first to examine the environmental effects of mining cobalt-rich crusts. These rock-hard, metallic layers, which form on the side of underwater mountains called seamounts, are among three deep-sea resources that have been proposed to the ISA as a target for mining. In 2020, a two-hour operation funded by the Japanese government excavated a roughly 120-metre-long strip of cobalt-rich crust on a seamount in the northwest Pacific Ocean, as a test run for mining activities.
To investigate the operation’s effects, scientists reviewed video footage collected by a remotely operated vehicle. They found that, in the year after the excavation, the density of active swimming animals, such as fish and shrimp, dropped by 43% in areas directly affected by sediment kicked up by mining, and by 56% in adjacent areas…
