February 23, 2026 — Negative consequences of deep ocean mining activity are no longer found only on the seafloor. This controversial practice has now become a midwater problem as well, with potential impacts reaching hundreds of feet above the ocean floor in every part of the world.
A new study is the first to show that waste discharged from mining ships into the midwater “twilight zone” of the Clarion-Clipperton Zone (CCZ) could disrupt food webs hundreds of feet above the seabed.
Researchers from the University of Hawaiʻi at Mānoa found that more than half of the zooplankton and roughly 60 percent of the micronekton living between about 650 to 4,900 feet (200 to 1,500 meters) would be exposed to mining plumes.
Because these animals feed larger predators, the effects would ripple upward to fish, seabirds, and marine mammals.