Plate Nº 95 · recorded November 15, 2026
Biology & EvolutionReported finding
Each Deep-Sea 'Metal Potato' Houses a Unique Micro-Ecosystem
Scientists cracked open 244 polymetallic nodules from the deep Pacific and found unique micro-ecosystems that mining could erase forever, they report in Scientific Reports.
By Marcus Bennett4 min read725 words
In brief
- Researchers examined 244 polymetallic nodules collected in 2019 from depths of 4-6 km in the Clarion-Clipperton Zone.
- Nodule communities 1,000 km apart were more similar to each other than to nearby sediment communities.
- The study, published in Scientific Reports, warns commercial mining could cause irreversible biodiversity loss.
- 153 nodules came from a BGR contract area; 91 from a Global Sea Mineral Resources (DEME) contract area.
By Marcus Bennett
Scientists examined 244 polymetallic nodules pulled from the deep Pacific and found that every one of these so-called metal potatoes hosts a community of microscopic animals that exists nowhere else on the surrounding seafloor.
The study, published in Scientific Reports, shows that the interior life of the nodules differs sharply from the life in the sediment around them — even when nodules lie 1,000 kilometers apart. For anyone tracking the deep-sea mining debate, that is the operative fact: protecting sediment habitats alone will not preserve this biodiversity.
"Our findings point out that commercial mining may result in an irreversible loss of undescribed and unique biodiversity associated to nodules," said deep-sea biologist Sabine Gollner of the Royal Netherlands Institute for Sea Research. "This needs to be considered in environmental management of deep-sea mining."
Why do these nodules matter?
Polymetallic nodules stud the seafloor across the Clarion-Clipperton Zone, and they are loaded with nickel, cobalt, copper, iron and manganese — metals our society consumes at a growing rate. That demand makes the nodules a target for a speculative mining industry.
The problem is time. A mining machine can pluck a nodule from the seafloor in minutes, but the nodule took millions of years to form. Scientists warn that mining could destroy an ecosystem we barely understand before we have finished describing it.
How was the study done?
Researchers collected the nodules in 2019 aboard the German research vessel RV Sonne during an expedition to the Clarion-Clipperton Zone, part of the JPI Oceans Mining Impact II project. The team lowered a box corer to depths of roughly 4 to 6 kilometers (2.5 to 3.7 miles) to retrieve chunks of seafloor sediment along with the nodules embedded in it.
The 244 nodules came from two contract areas:
- 153 from an area where Germany's Federal Institute for Geosciences and Natural Resources (BGR) holds an exploration contract from the International Seabed Authority.
- 91 from an area where the Belgian company Global Sea Mineral Resources, a subsidiary of DEME, holds an exploration contract.
The researchers froze the nodules and their inhabitants, then took them to a lab for analysis.
What lives inside a nodule?
Earlier biodiversity surveys in the Clarion-Clipperton Zone focused on organisms living in the sediment or clinging to nodule surfaces. The deep seafloor is mostly fine mud, and many animals need something solid to attach to; the nodules supply that hard substrate.
"We already knew that polymetallic nodules provide attachment surfaces for deep-sea organisms, but very little was known about the animals living inside them," marine genomicist Coral Diaz-Recio Lorenzo told ScienceAlert.
When the team cracked the nodules open, they found miniature ecosystems tucked into the cracks and pores:
- Roundworms and crustaceans — the most common inhabitants.
- An "armored amoeba" called Thurammina, which dominated its kind.
- Bristleworms, mud dragons, tardigrades and other rarer animals in just a few nodules.
"What surprised us most was how different the communities living inside nodules were from those in nearby sediments," Diaz-Recio Lorenzo said. "Remarkably, nodule communities collected from areas separated by approximately 1,000 kilometers were more similar to one another than to the surrounding sediment communities."
Are these ecosystems ancient?
Microscopy revealed fossils of diatoms, radiolarians and sea sponges embedded in the nodules' ancient layers. Scanning electron microscope images showed sponge spicules — the structural needles of sponges — plus the foraminiferan Saccorhiza sp., which builds its shell-like test from sponge spicules.
"The presence of… biogenic particles within crevices indicated that at least some cavity structures were colonized by ancient organisms, although this does not necessarily demonstrate in-situ colonization at the time of incorporation," the team writes. Even so, they conclude the nodules "may have provided a habitat on the seabed for millions of years."
What does this change for mining decisions?
If the International Seabed Authority approves mass nodule removal, these ancient ecosystems will be destroyed for good. Because nodule communities differ from sediment communities, guarding the mud alone will not save them.
"Large-scale nodule removal could therefore result in irreversible losses of unique species and ecological communities that we are only beginning to understand," Diaz-Recio Lorenzo added.
How these microscopic worlds feed into global nutrient, carbon and ecological cycles remains unknown — and scientists are racing to find out before the nodules come up.
via sciencealert.com (Source)
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News editor covering regulation, policy and their impact on general science news at SciBeat.
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