A 1979 Deep-Sea Mining Test Left Seafloor Food Depleted 44 Years Later
Sediment from tracks made by a mining machine in the Pacific’s Clarion-Clipperton Zone still contains less organic matter, and matter of poorer quality, than undisturbed seabed, a University of Liverpool study published in Elementa found. Researchers linked the depleted food supply to lower numbers of larger animals and single-celled organisms, but the study does not prove that one caused the other.
Bottom line — The University of Liverpool team says long-term monitoring should inform assessments of mining in the Clarion-Clipperton Zone.
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The SMARTEX team collected sediment samples in 2023, at depths of about 4,800 metres.
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Organic matter sinking from the surface is a key food source for animals on the seafloor, the University of Liverpool said.
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Researchers compared the mined tracks with nearby disturbed ground and an undisturbed control site.
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The Natural History Museum reported a mixed picture at the same site: some mobile animals had returned, while large animals fixed to the seafloor remained scarce.
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The Natural History Museum said resettled sediment had no detectable negative effect on animal numbers in its study.