Seabed mining: What Do You Need to Know and What Actions You Can Take

March 4, 2021
Don't Mine the Deep, photo curtosy of Pew Charitable Trusts. Illustration of vacuum on the seafloor next to fish and coral

The rush to mine this pristine and unexplored environment risks creating terrible impacts that cannot be reversed.” -- Sir David Attenborough

On February 19th, MES was joined by Liz Schotma from The Surfrider Foundation, and Lee First, from the Twin Harbors Waterkeepers, for a presentation on seabed mining and upcoming Clean & Abundant Water Lobby Week, March 1-5, 2021.

So what is seabed mining and why is this emerging industry a concern? Seabed mining is the extraction of minerals and metals from the sea floor, which can range from beaches and near-shore low tide zones to ocean depths of 200 meters (about 656 feet). The three major forms of these materials are manganese nodules found in the abysmal plane, cobalt-rich crusts located in seamounts, and seafloor massive sulfides in deep-sea hydrothermal vents. Mining ocean ecosystems has emerged as a response to not only the depletion of terrestrial sources of mined resources, which have become increasingly difficult to extract, but also due to these materials being essential for improving green technologies in sustainable development.

However, with seabed mining there is a need to take a precautionary approach, as history is fraught with hard lessons learned from destroying ecosystems we have yet to fully understand. The ocean in an ecosystem that we have only explored about 0.01% of, with new species being learned about in every new expedition. Additionally, the three materials are located in biologically sensitive and significant habitats. Manganese nodules rich in cobalt, nickel, and lithium, are found in silty beds, creating a hard structure for sea life to attach to and depend upon for their survival. These nodules grow at an extremely slow rate—about a millimeter every thousand to a million years—so once they are gone, they are gone! Cobalt crusts, which can be centimeter to six or more inches thick and are rich with rare earth metals, are found in under-water biodiverse hotspots with productive oxygen and nutrient dense habitats that are essential for the ocean food-web and commercial fishing—think of an oasis in a desert. The extraction process involves plowing the crust up, similar to mountain-top removal. Massive sulfides build up around hydrothermal vents as metal rich chimneys. These are very unique ecosystems in that they have evolved to be chemosynthetic, rather than photosynthetic, meaning that the sun could die, and these ecosystems would more than likely continue undisturbed. While these ecosystems are extremely difficult to study, some scientists believe that these chemosynthetic ecosystems are where life on our plant originated from. However, to extract massive sulfides from these hydrothermal vents, these structures need to be knocked down and completely destroyed.

Not only do these extraction methods consist of destroying the physical structure, reducing habitat for sea life and ocean biodiversity, but turbidity plumes created from slurries of silt and mud are the result of extraction methods as well. Although the precise risk is uncertain, these silty plumes could travel anywhere from 10-100 kilometers (about 6-62 miles) from extraction sites. These plumes not only make it difficult for sea life to navigate through, but additionally creates light pollution, cutting photosynthetic life forms crucial for maintaining the ocean food-web off from sunlight. Additionally, extraction methods create noise and thermal pollution, all contributing to decreasing the biodiversity of the ocean and coming into conflict with fishing and other ocean industries. Ultimately with so little understanding of the ocean, even less is understood about how to restore these extraction sites. If you’re interested in reading about some studies on ocean extraction restoration, look into the DRISCOL project: “Deep-seabed mining lastingly disrupts the seafloor food web” (

Even though this might be an anxiety-inducing emerging issue alongside climate change, there is still a window of opportunity to address destructive seabed mining before it’s at our shores. While there has been some research done on mineral content in in Grays Harbor, Columbia Estuary, and Cape Disappointment areas, no actual mining has been done. With no specific regulations on seabed mining existing in Washington state, organizations such as the Surfrider Foundation and Waterkeepers, have partnered with the Pew Charitable Trusts to protect our vulnerable near-shore waters by banning seabed mining in state waters. With Oregon banning near-shore seabed mining in 1991 and working with California on a state-wide ban, Senate 5145 is currently being worked on currently in Washington.

March 1-5 2021 is Clean & Abundant Water Lobby Week, where individuals can join several organizations who work on water quality (and quantity) issues across the state to virtually advocate for some important laws that safeguard our waters. Even if you have no experience in lobbying, you can get trained with policy experts at your side to help make it easier to talk to your elected officials about four key bills that could become law this year. If you’re interested in learning more and learning how to virtually advocate for water protection, visit: Additionally, you can join the Facebook event at:

If lobby week doesn’t sound like your thing right now, but you still want to take action here or learn more, visit the Surfrider Foundation website at and the Twin Harbors Waterkeepers website at

Watch Liz and Lee’s presentation on Youtube at