Researchers working in the Clarion‑Clipperton Zone have cataloged 788 species on the abyssal plain and warn that suction‑based deep‑sea mining could substantially alter biodiversity. Experimental plume simulations caused a 37% drop in macrofauna density in directly affected areas, and about 74% of abyssal animals inhabit the easily disturbed top sediment layer. Teams also discovered roughly 300 new annelid species. Scientists call for long‑term monitoring and detailed species‑level taxonomy to assess recovery and guide policy.
Scientists Catalog 788 Deep‑Sea Species — New Study Warns Deep‑Sea Mining Threatens Abyssal Life
Scientists Found Ocean Creatures in Grave DangerFrancesco Ricciardi - Getty Images
Researchers mapping the seafloor of the Clarion‑Clipperton Zone (CCZ), a vast abyssal plain between Mexico and Hawaii, have cataloged 788 species and warned that commercial deep‑sea mining could seriously damage this little‑known ecosystem.
The CCZ is rich in polymetallic nodules and other deposits that contain copper, cobalt, nickel, gold, silver, zinc and rare earth elements — minerals increasingly sought after by industry. Mining systems planned for the abyss use strong suction to lift nodules and sediment from the seabed, producing sediment plumes that can smother or injure animals and alter habitat structure across wide areas.
What Scientists Found
Led by Thomas Dahlgren of the University of Gothenburg and collaborators from multiple institutions, teams working at depths exceeding 4,000 meters (about 13,000 feet) combined visual surveys, specimen collection and DNA analysis to inventory species before large‑scale industrial activity begins.
“We found no evidence for change in faunal abundance in an area affected by sediment plumes from the test mining; however, species dominance relationships were altered in these communities, reducing their overall biodiversity,” the authors wrote in Nature Ecology & Evolution. They stress the value of species‑level taxonomic work for assessing biodiversity risk.
Among the remarkable organisms recorded are sea spiders, pink sea pigs, chimaeras, numerous annelid worms, transparent sea cucumbers, glass sponges and solitary corals that resemble spectral blossoms in the dark. Teams from the University of Gothenburg and the Natural History Museum in London identified roughly 300 previously undescribed annelid species during CCZ expeditions, although some fragile animals were damaged by rapid pressure changes on retrieval.
Evidence Of Impact
Experimental tests simulating sediment plumes from suction‑style mining showed a 37% decline in macrofauna density within the direct path of the extraction device. Scientists note that about 74% of abyssal fauna live in the uppermost sediment layer, which is especially vulnerable to disturbance. Physical impact can damage gills and feeding structures, and mobilized metals can reach toxic concentrations in disturbed sediments.
In 2022 a commercial‑scale test in the Eastern Pacific recovered more than 3,000 tons of metal, demonstrating the resource potential but also highlighting risks: suspended particles, altered food‑fall patterns (marine snow), and noise or other disturbances that could affect acoustically sensitive marine mammals such as whales and dolphins.
“Longer‑term monitoring of the impacted sites would enable better evidence on rates of recovery,” the researchers noted, adding that areas affected by plume settlement may change more slowly than directly disturbed sites and should be prioritized in future impact studies.
What’s Next
Scientists recommend intensified, long‑term ecological monitoring, thorough species‑level taxonomy, and cautious, evidence‑based decision making before permitting commercial extraction. Because many abyssal species are poorly known or only detectable via DNA, preserving baseline data is critical to assess loss and recovery.
Bottom line: The discovery of hundreds of species in the CCZ underscores both the biological value of the abyssal plain and the potentially irreversible consequences of large‑scale seabed mining. Effective protection will depend on rigorous science, precautionary management, and long‑term monitoring.
