This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Protected areas have been set up to shield deep-sea life from the impacts of seabed mining in the Pacific Ocean. However, new research led by scientists at Plymouth Marine Laboratory (PML) and published in Nature Ecology & Evolution highlights an opportunity to make these protections even more effective.
The study suggests that adding a small number of strategically located protected areas could help transform existing reserves into a more connected network, enabling tiny drifting larvae that have been cast adrift after disturbance to recolonize more successfully. The research team focused on the Clarion-Clipperton Zone (CCZ), a stretch of abyssal seafloor in the central Pacific roughly the size of Europe, lying around 5,000 meters (16,400 feet) down. This area has become a global hot spot for prospecting because its floor is scattered with polymetallic nodules, which are potato-sized lumps of rock rich in nickel, cobalt and other metals used in all electronics.
More than 1.1 million square kilometers (425,000 square miles) of the CCZ are already licensed for mining exploration, and commercial extraction could begin within years. However, governments, scientists and environmental groups have long been concerned about the significant impact mining operations would have on these types of valuable habitats. To protect biodiversity from the impact of mining, the International Seabed Authority set aside a network of 13 "no-mining" reserves, called "Areas of Particular Environmental Interest (APEIs)," covering nearly 2 million square kilometers (772,000 square miles).
The reserves were chosen mainly to represent a spread of different seafloor habitats, but ensuring that marine life in one reserve could help replenish another if it was damaged was not a key consideration. Using computer models of ocean currents across the whole CCZ, the PML-led team, which included partners from the National Oceanography Centre (UK), University of Plymouth (UK), Aarhus University (Denmark) and the Joint Nature Conservation Committee (UK), tracked the likely journeys of larvae drifting just above the seabed, where deep-sea larvae are known to concentrate. The team found that even larvae capable of drifting for over two months typically traveled less than 100 kilometers (62 miles).
In contrast, the protected reserves sit between 200 and 800 kilometers (124 and 497 miles) apart, and fewer than two in every 10,000 simulated larvae released from one reserve ever reached another. Molly James, lead author of the study and a marine ecosystems modeler at PML, commented, "The existing deep-sea reserves are distributed across the ocean but with significant gaps between them. Our modeling suggests that rather than functioning as a connected network, they currently operate more as separate conservation areas." Discover the latest in science, tech, and space with over 100,000 subscribers who rely on Phys.org for daily insights. d research that matter—daily or weekly.
The researchers also modeled what would happen if mining went ahead and disturbed larval supply within the licensed mining areas themselves. Under that scenario, the protected reserves currently contribute only a small fraction of the larvae needed to help mining-affected areas recover, with most replenishment instead coming from the seafloor nearby that has no legal protection at all. The team then used the same models to identify where new protected "corridors" could be added to stitch the existing reserves together.
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