Restoring sea floor after mining may not be possible, Researchers

The value of polymetallic nodules

Particularly sought after are potato-sized nodules rich in cobalt, nickel, copper, and manganese, found abundantly in the central Pacific Ocean. While companies claim they can extract these nodules with minimal environmental risk, ocean advocates warn that such activities could threaten fragile ecosystems that remain poorly understood.

Findings from DEEP REST project

Research from the DEEP REST project highlights the irreversible loss of biodiversity when nodules are removed. Jozee Sarrazin from the French Institute for Ocean Science emphasized that restoration efforts so far have been short-term, with ecosystems failing to recover within a few years. "If restoration is possible, it will take a very long time," he noted, indicating recovery could span centuries.

Biodiversity at risk

The deep sea is home to millions of species, including unique fauna like sponges and soft corals that rely on nodules for attachment. Studies show that removing nodules decreases biodiversity and disrupts ecosystem functions, leading to recovery timelines of thousands of years.

Future of restoration research

While some restoration research is underway, results are still pending. Biologist Sabine Gollner discussed experiments with artificial nodules made of deep-sea clay, noting that the slow growth rates in these environments complicate restoration efforts.

Recommendations for mining regulations

Researchers recommend prohibiting the extraction of massive sulfide deposits found near underwater vents, which host unique biodiversity. Gollner advocates for integrating restoration goals into the mining code being negotiated by the International Seabed Authority, but stresses that such efforts should not be used to justify broader mining activities.