Study warns deep-sea mining waste threatens marine food chain

A new peer-reviewed study published in Nature Communications on Thursday warns that waste from deep-sea mining could disrupt life in the ocean’s “twilight zone”, a key midwater layer supporting much of the marine food web.Researchers from the University of Hawaii‘s School of Ocean and Earth Science and Technology (SOEST) found that over half of zooplankton and 60% of micronekton could be affected by sediment plumes from mining trials in the Clarion-Clipperton Zone (CCZ). These particles, far less nutritious than natural food sources, risk triggering a “junk food” effect up the food chain.“When the waste released by mining activity enters the ocean, it creates water as murky as the mud-filled Mississippi River,” lead author Michael Dowd says. “It dilutes the nutritious natural food particles usually consumed by tiny, drifting zooplankton”.Spanning 200 to 1,500 metres below the surface, the twilight zone hosts fish, squid and jellyfish critical to ocean health and carbon cycling. The system is highly sensitive to changes, the authors of the study say.“Our research suggests that mining plumes don’t just create cloudy water — they change the quality of what’s available to eat, especially for animals that can’t easily swim away,” SOEST deep-sea ecologist Jeffrey Drazen said. “It’s like dumping empty calories into a system that’s been running on a finely tuned diet for hundreds of years.”Figure from: Deep-sea mining discharge can disrupt midwater food webs.Despite this, around 1.5 million square kilometres of the CCZ, which is a vast area between Hawaii and Mexico, are already licensed for exploration. Waste disposal methods remain largely unregulated, even as demand for critical minerals climbs. The International Energy Agency projects demand for copper and rare earths will rise by 40%, and for nickel, cobalt, and lithium by 60%, 70%, and 90%, respectively.“Deep-sea mining has not yet begun at a commercial scale,” co-author and SOEST professor of earth sciences Brian Popp says. “This is our chance to make informed decisions”Not finalOther studies seem to differ. A separate UK-led research published earlier this year suggests recovery may be possible. The National Oceanography Centre found signs of ecological rebound decades after early mining tests.The Metals Company (NASDAQ: TMC), a pioneer in deep-sea mining, says that study supports its own findings. “It proves [that] … recovery is not only possible but likely within decades,” CEO Gerard Barron told MINING.COM at the time.He also pointed to a possible mitigation strategy, “leaving some nodules intact to support recolonization.” TMC has already pledged to leave 30% of its contract areas untouched to aid recovery. Supporters argue deep-sea mining is essential to meeting clean energy goals, while critics urge caution until long-term impacts are better understood.“Before commercial mining begins, we must carefully evaluate where waste is released,” Drazen warned. “If we get it wrong, we could harm ocean communities from the surface to the seafloor.”Weiter zum vollständigen Artikel bei Mining.com Weiter zum vollständigen Artikel bei Mining.com