“Junk food” effect: Study coauthor Brian Popp of the University of Hawaii at Mānoa described the particles as “basically junk food” for plankton.

Deep-sea mining for valuable metals may have unintended and far-reaching consequences for marine ecosystems. A new study published November 6 in Nature Communications warns that sediment plumes released during mining operations could disrupt plankton the foundation of ocean food webs potentially triggering a cascading ecological impact from microscopic organisms to large marine predators.

Key Findings

• Sediment plumes reach mid-water ecosystems: Mining activities at depths of 4,000 meters release waste plumes that can spread upward to around 1,500 meters, affecting open-water species.

• Plankton mistake sediment for food: Researchers found that plankton prefer particles around 6 micrometers in size — the same size as sediment particles released during mining.

• Low nutritional value: Samples collected near a pilot operation by The Metals Company showed plume particles had extremely low protein content compared to natural food sources.

• Risk of starvation cascade: If plankton consume nutrient-poor sediment instead of real food, it could lead to starvation at the base of the food chain — impacting fish, marine mammals, and top predators.

• Long-term ecosystem damage: Beyond plankton, seabed mining already threatens fragile deep-sea microbial communities and bottom-dwelling organisms through habitat disruption and sediment clogging.

Scientists say the findings add urgency to calls for stricter regulation of deep-sea mining before large-scale commercial operations begin.