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A leading deep-sea researcher told Marianas residents last week that damage from proposed seabed mining operations could persist for centuries, with some ecosystems never recovering within human timescales.
Jeffrey Drazen, a University of Hawaii oceanography professor, presented findings during a Dec. 2 webinar showing that disturbed deep-sea areas haven’t bounced back even after 44 years of monitoring. The recovery timeline for some disturbed areas could exceed 100 years, he said, while animals living directly on mineral nodules would never recover because their habitat takes millions of years to regrow.
“Areas in a region that are first mined will likely not have recovered by the time most of the area is mined,” Drazen told the approximately 100 participants who logged into the online session organized by Tåno Tåsi yan Todu and Northern Marianas College. “You need to plan on whole system impacts.”
The presentation comes as the Bureau of Ocean Energy Management considers commercial leasing for minerals on the outer continental shelf offshore the Commonwealth of the Northern Mariana Islands. Federal officials opened a 30-day comment period in November that closes Dec. 12, drawing criticism from scientists and community advocates who say the timeline is too short for such consequential decisions.
Drazen’s research focuses on deep-sea fish ecology and mining impacts. He shared data from the Clarion-Clipperton Zone in the Pacific, where test mining has left visible scars on the ocean floor decades after equipment passed through.
The scale of potential operations dwarfs typical industrial projects. A single mining operation could directly disturb roughly 10,000 square kilometers of seafloor over a 15-year lease period, Drazen said. When accounting for sediment plumes that spread beyond collection sites, the affected area could balloon to 50,000 square kilometers, roughly the size of Costa Rica.
“This activity could potentially cover vast areas of the ocean,” he said.
The mining targets two types of mineral deposits. Polymetallic nodules, which look like potatoes scattered across flat abyssal plains at depths of 4,000 to 6,000 meters, contain manganese, cobalt, and nickel. Ferromanganese crusts coat the tops of seamounts, underwater mountains that support thriving coral forests and serve as feeding grounds for fish.
Both formations took millions of years to develop as dissolved metals in seawater slowly accumulated on rocks or sediment grains.
Kelsey McClellan, natural resources management program coordinator at Northern Marianas College, who sailed on a 2025 Ocean Exploration Trust expedition exploring Mariana waters, said the density of life observed on seamounts surprised her.
“The diversity and the density of organisms was, I was really astonished,” McClellan said in an interview with The Guam Daily Post last week following the Drazen webinar. “The more that I learned, the more I realized just how critical these seamounts are for our ecosystems and for our fisheries.”
Mining operations create two main disturbance zones, she explained. Collection equipment scrapes mineral deposits from the seafloor or seamount surfaces. Then ships discharge unwanted mud and seawater back into the mid-water column between 1,000 and 3,000 meters deep.
That discharge plume carries risks that extend beyond the collection site. Drazen’s team found toxic metals are released from disturbed sediments, and the muddy water dilutes marine snow – the organic particles that feed zooplankton, which in turn support the small fish and squid eaten by tuna and other commercially valuable species.
“53% of the plankton taxa at these depths are these marine snow or particle feeders,” Drazen said. “So, they have the potential to starve or have reduced feeding success because of all of the discharge of this mud.”
The food web disruption could ripple up to affect fisheries. Between 1% and 12% of tuna caught annually in some Pacific management areas comes from waters with existing exploration licenses for mining, according to research Drazen presented.
Amanda Dedicatoria, a freelance science writer who also participated in the 2025 Nautilus expedition, said the environmental stakes demand careful consideration.
“Mining could impact the health and abundance of the fish we eat, contaminate our waters with toxic heavy metals, and affect how our ocean regulates the climate,” she told the Post. Dedicatoria accompanied McClellan during the interview that followed the Drazen webinar.
Both expressed shock at how quickly the proposal advanced. The 30-day comment window came during the holiday season, they noted, limiting time to inform communities about the complex issue.
“Thirty days is insufficient to respond comprehensively to this issue, which is one that is environmental, cultural, and economic and could stand to affect our communities for generations,” Dedicatoria said.
The knowledge gaps trouble researchers. Drazen said his team’s baseline study in the Clarion-Clipperton Zone, considered the best-studied deep-sea mining area, visited sampling sites just twice. That captured seasonal variation but missed longer-term patterns needed to distinguish natural changes from mining damage.
“Two expeditions does not capture the complete seasonal cycle or inter-annual variability,” he said. The RFI area offshore the Commonwealth of the Northern Mariana Islands remains largely unexplored by science.
McClellan pointed out another concern: The proposed mining area sits in federal waters beyond the three nautical miles where the Marianas has jurisdiction. That means limited territorial control over operations or monitoring.
“It would be very unlikely that we would see any of the revenue generated from the deep-sea mining opportunities,” she said, noting one company offered American Samoa just 1% of revenue under a cost-sharing agreement.
Community organizations are mobilizing to help residents submit comments before the deadline. The activist group who call themselves Prutehi Guåhan will host a workshop Tuesday at noon featuring attorneys from Earthjustice, a nonprofit environmental law firm that recently submitted comments on a similar proposal for American Samoa.
Monaeka Flores, head of Prutehi Guåhan, said the islands face permanent environmental damage for minimal economic benefit.
“The islands will not benefit from any of the wealth gathered from deep-sea mining,” Flores said. “We may see 1% or less than 1%, and that’s probably over a decade, and at what cost?”
She called the process “a new form of colonization” that threatens territorial sovereignty and criticized claims that mining supports green energy transitions as “greenwashing.”
“The deep sea is one of the most vulnerable and most critical ecological areas of the planet,” Flores said. “We don’t even understand all of the ecology. We don’t understand the impacts of this tech, and that is enough to say that we shouldn’t move forward with this.”
Dedicatoria encouraged residents not to feel intimidated by the federal comment process.
“A comment only needs to be a couple of sentences long,” she said. “How do you feel about this issue and how it will affect us in the present and our future generations?”
The community workshop registration is free, but space is limited; it is available at https://tinyurl.com/nodsm. The group has created a toolkit to assist residents at https://tinyurl.com/dsmtoolkit.
Comments on BOEM’s request for information can be submitted through the Federal eRulemaking Portal at regulations.gov by searching for BOEM-2025-0351 or by mail to the Bureau of Ocean Energy Management, Pacific Region, Office of Strategic Resources, 760 Paseo Camarillo (CM 102), Camarillo, California 93010.
