For all of humanity’s ventures to outer space, we’ve yet to see 99.999% of the deep-sea floor. In the latest subaquatic news, researchers discovered some 4,000 marine species, 88% of which were new creatures, during a deep-sea mining trial, no less.
A team of European marine biologists and The Metals Company, a deep-sea mining firm, spent five years peering within the depths of the Clarion-Clipperton Zone, a section of the deep sea between Mexico and Hawaii. The unprecedented collaboration encountered thousands of marine critters thriving beneath 13,123 feet (4,000 meters) underwater, including odd bristle worms, bony spiders, tiny snails, mussels, and more.
More concerning, the team confirmed the mining vehicle negatively impacted wildlife, though with some caveats. A paper on the project was published recently in Nature Ecology & Evolution.
Hidden in the depths
The study’s initial purpose was to assess the impact of deep-sea mining technologies on the marine environment. Deep-sea mining extracts critical minerals like lithium, cobalt, or nickel from the depths of the sea. These minerals, as their name suggests, are critical ingredients for renewable energy technologies, such as solar panels, wind turbines, or electric vehicles.
But they’re rare and perpetually in short supply, prompting various stakeholders to seek new sources of critical minerals, including underexplored regions of the deep sea. Experts have yet to grasp the full extent to which mining could harm ecosystems, and as a result, no commercial operations have been approved by the International Seabed Authority (ISA), which oversees human activity in international waters.
A treasure trove of critters
The study was based on one of many investigations that the ISA approved for preliminary assessments of mining impact. In a comment to BBC News, the researchers clarified that their data was independent, as The Metals Company was “able to view the results before publication but was not allowed to alter them.”
Researchers sampled sediment from the Clarion-Clipperton Zone several times before and after mining tests, evaluating whether and how biodiversity changed in the region. These 80 samples revealed 4,350 deep-sea specimens, 88% of which could be identified as nearly 800 different species.
“Historically it was thought that deep-sea ecosystems would be very stable and unchanging over time because of how remote they are from the ocean surface,” Eva Stewart, study lead author and a PhD student at the University of Southampton in the U.K., explained in a statement. “But we actually found there was quite a significant amount of natural change over the time we were studying.”
Mining doesn’t help, but…
The impact of mining was also very clear, the paper noted, as the mining vehicle’s presence prompted a decline in the number of animals and species diversity by 37% and 32%, respectively. When mining machines zoom past the sea floor, they remove roughly the top two inches (five centimeters) of the sea floor—where “most of the animals live,” Stewart told the BBC.
“So obviously, if you’re removing the sediment, you’re removing the animals in it too,” she added. However, some species tended to cope better with the disruption, eventually crawling back to their original locations after the sediment settled.
“We were expecting possibly a bit more impact, but [we didn’t] see much, just a shift in which species were dominant over others,” Adrian Glover, study senior author and a marine biologist at the Natural History Museum in the U.K., added to BBC.
Overall, the team, despite its findings, concluded that it is still challenging to “say with certainty how mining activity impacts other animals in these deep-sea environments,” according to the release. One reason for this is that the study, in confirming hundreds of new species, further cemented humanity’s poor understanding of deep-sea environments.
To learn more, we’ll just have to keep going back—even if that itself is a risk to wildlife.
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