During World Ocean Week 2025, Innovation & Tech Today is turning the spotlight on a critical issue threatening our planet: deep-sea mining. As nations push to extract essential minerals from the ocean floor, scientists like Dr. Jeffrey Drazen, a professor of oceanography at the University of Hawai’i at Mānoa, are sounding the alarm about unseen consequences.
Midwater Ecosystems
Scientists are increasingly concerned about what deep-sea mining could mean for the midwater zone. Found between 200 and 1,000 meters down, this part of the ocean may not be well known, but it’s full of life and keeps ecosystems balanced.
“The midwater zone hosts a very unique biodiversity from microbes to fishes,” says Dr. Jeffrey Drazen, a professor of oceanography at the University of Hawai’i at Mānoa and one of the world’s leading experts on deep-sea ecosystems. “It also hosts a fish biomass 100 times higher than the global annual fish catch.”
In addition to being home to many strange sea creatures, the midwater zone is a vital feeding ground for commercially important fish like tuna and swordfish.
“Midwater communities break down organic matter and regenerate nutrients that end up back in the surface waters to drive phytoplankton production, the base of the food web,” Drazen explains. “These creatures also help remove carbon from the atmosphere by transporting it to deeper waters—a natural process that helps mitigate climate change.”
Midwater Zone
The deep sea’s stability is also what puts it at the highest risk. “It is a vulnerable place because it is naturally quite stable in most parts of the ocean,” Drazen notes. “The pace of life is slow. Disturbances may thus have a greater effect than they would in coastal habitats.”
In places like the Clarion-Clipperton Zone (CCZ)—a common place for mining—the water is crystal clear. That clarity makes the area especially sensitive, so even small disturbances, like a cloud of brown, muddy sediment, can cause major disruptions to the ecosystem.
“Discharge of mine waste likely will affect [animals] even at very low concentrations,” says Drazen. “Studies show fragile organisms like jellies suffer from exposure to such ‘mud clouds.’”
Impact of Mining
So what happens when mining operations discharge sediment into the midwater zone?
According to Drazen, modeling shows sediment plumes can stretch up to 40 kilometers horizontally and a few hundred meters vertically, forming a kind of “pancake” in the water column. Over a year, models suggest between 3,000 and 5,000 cubic kilometers of ocean could be exposed.
“That is a lot,” Drazen emphasizes.
He’s mostly concerned about the dissolved plume—not just particles, but metals and chemicals that don’t settle.
“This may behave differently because the sediment settles, but the dissolved components do not,” he explains. “I’m particularly concerned about dissolved metal concentrations building up over the years and entering food webs.”
This could threaten not just midwater animals, but the seafood supply we depend on.
“I’d really like to know if deep-sea mining could contaminate tunas and commercially important fish with metals delivered through the midwater food web,” Drazen says.
Marine Life Affected
Beyond toxic exposure, plumes can interfere with the basic behaviors of midwater species.
“Sediment may block the vision of animals that find mates and lure prey using bioluminescence,” Drazen says. “It can dilute the detritus that is the food supply for many zooplankton, leading to starvation, block the gills of fishes and shrimps, or introduce toxic metals to the food web.”
He stresses that these are not just hypotheticals: “These are all possible risks that need additional research.”
Regulatory Conflicts
As the International Seabed Authority (ISA) debates how to regulate deep-sea mining, major geopolitical moves are also unfolding.
In a controversial April 24, 2025, executive order, President Donald Trump moved to expedite U.S.-issued licenses for seabed mining under the Deep Seabed Hard Mineral Resources Act. The Metals Company, a deep-sea mining firm, praised the decision.
The U.S. remains one of the few nations that has not ratified the U.N. Convention on the Law of the Sea, instead maintaining its own separate licensing regime.
The ISA strongly opposes Trump’s move, warning it may undermine environmental protections.
Better Oversight
The ISA does recommend baseline monitoring of midwater ecosystems. But Drazen says the current guidance is vague, especially when it comes to where waste can be discharged.
“There is a weakness in that there is no specification on what depth discharge could occur, except it should be chosen to minimize environmental risks,” he says.
Drazen thinks there’s definitely room to tighten up the current ISA guidelines. “There is a weakness in that there is no specification on what depth discharge could occur, except it should be chosen to minimize environmental risks,” he points out.
He believes that keeping waste discharge closer to the seafloor could help limit the damage. But more importantly, he’s clear about what solid, science-backed policy should look like: “In any area that may be mined, it’s critical for adequate ecosystem baselines to be established… That means years of ecological data.” He also stresses the need for a full environmental impact statement (EIS)—one that’s peer-reviewed and open to public comment.
Research Is Urgently Needed
Dr. Jeff Drazen has spent over 1,000 days at sea, authored more than 130 scientific publications, and secured over $20 million in research funding to study ocean ecosystems. His message is clear: we’re still learning how the ocean works—and how deep-sea mining could disrupt it.
“We need more studies on the susceptibility of these fragile midwater animals,” he stresses.
Until we understand the full impact, opening the seafloor for mining could come at a cost the planet—and humanity—might not be ready to pay.
