Scientist warns deep-sea mining could lead to the extinction of CNMI’s biodiversity

By Mar-Vic Cagurangan

The waters of the Northern Marianas contain extremely high biodiversity, including endemic species, which will face extinction should seabed mineral extraction take place in the region, a deep-sea scientist from the University of Hawaii Manoa warns.

“That’s an important consideration,” Dr. Jeffrey Drazen said, noting that the proposed deep-sea mining off the CNMI’s shore would entail a process that might cause long-term damage to the marine habitat.

Jeffrey Drazen

Drazen discussed his research on the impact of deep-sea mining on ecosystems during a webinar hosted by the environmental group Tano Tasi Yan Todu on Dec. 2.

The group, which comprises scientists, educators and activists, hastily organized the online forum amid the looming deadline for submission of public comment on the Bureau of Ocean and Energy Management’s call-out for industry interest in deep-sea mining.

The U.S. government is seeking to explore deep-sea mining in federally managed waters offshore the Northern Mariana Islands in line with the Trump administration's bid to facilitate domestic production of critical minerals, ensuring secure supply chains for U.S. defense, infrastructure and energy sectors.

The bureau’s  request for information  has set off the initial steps that could potentially lead to leasing the seabed for mineral harvesting in the CNMI’s outer continental shelf.

Drazen said one of the resources that is of interest for mining the cobalt or polymetallic crusts atop the seamounts in the Northern Marianas’ exclusive economic zone.

“Mining in this case is not just sucking these loose nodules off the mud, but they're grinding the crust off of the rocks at the seamount, and they're doing that to a depth of about 5 or 10 centimeters,” he said.

“Most of the companies that are interested in doing this right now are targeting the flatter seamounts, which are called guyots, because it will be easier for their mining vehicles to operate in those, but that does not mean that steeper sides won't be mined,” Drazen said.

In terms of engineering, he added, the cobalt or polymetallic crusts are currently the lowest hanging fruit.

 “The areas that are being licensed at least in international waters today for cobalt crust mining are much smaller than the areas for nodule mining, and we're anticipating that impacts could be something like 250 sq.km over 15 years,” Drazen said.

He noted that previous research indicated low resilience in seamount ecosystems, which, like the abyssal plains, also contain nodules on which about half of the diversity lives.

“Do keep in mind nodules do occur on seamounts and could also be mined. Particularly on the deep flanks of those seamounts, you can find nodules,” Drazen said.

“It's important to realize that nodules take millennia to form, so mining them removes potentially a habitat that just will not come back over evolutionary timescales,” he added.

"We anticipate that full recovery may take 100 plus years. The animals living directly on the nodules will not recover because their habitat will take millions of years to regrow," he added.

To give a glimpse of the potential environmental risks from crust mining, Drazen cited previous research by a Japanese team that studied the impact of seamount disturbance.

“We're finding now—and our sampling is sparse—that some of these animals have relatively small ranges,” Drazen said. “And so because of the extensive nature of mining in particular areas of the ocean, that then presents an extinction risk for some of this biodiversity.”

During the study, the Japanese team created tiny tracks with a grinding vehicle, covering about a couple of hundred square meters, Drazen said.

“Some animals were alive between the grinding heads on the collector vehicle. It was definitely not commercial-scale mining," he said. "What they found was that mobile animals in the region seemed to avoid the area even 13 months after the mining activity occurred.”

Grinding activities also released metals and created noise that disturbed marine life.

“There have been a number of fishing activities on very deep seamounts down to depths of a little over a thousand meters in places like Australia, New Zealand, the North Atlantic, the Hawaiian island chain, and natural recovery from these fishing trawl impacts usually are incomplete after about 20 to 60 years,” Drazen said.

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