Potential impacts of deep seabed mining are not yet understood

A team of renowned biologists is calling attention to the potential impacts of deep seabed mining. The experts have found troubling scientific misconceptions that fail to represent the destruction that could be caused by future operations to extract minerals from the seabed.

The deep sea is home to the most remote habitats on the planet, and this region supports invaluable species and ecosystem services. The possibility of mining for copper, cobalt, zinc, manganese and other valuable metals on the seafloor has been gaining more attention in recent years. Deep seabed mining is not yet underway, but many companies are already prospecting.

“As a team of deep-sea ecologists, we became alarmed by the misconceptions present in the scientific literature that discuss the potential impacts of seabed mining,” said study lead author Professor Craig Smith of the University of Hawaii at Mānoa.

“We found underestimates of mining footprints and a poor understanding of the sensitivity and biodiversity of deep-sea ecosystems, and their potential to recover from mining impacts. All the authors felt it was imperative to dispel misconceptions and highlight what is known and unknown about deep seabed mining impacts.”

In a study published last month, Professor Smith and his colleagues detailed the impacts of mining on ecosystems in the water above extraction activities. The current paper emphasizes deep-seabed mining impacts on the seafloor, where habitats and communities would be permanently destroyed by mining.

“The bottom line is that many deep-sea ecosystems will be very sensitive to seafloor mining, are likely to be impacted over much larger scales than predicted by mining interests, and that local and regional biodiversity losses are likely, with the potential for species extinctions,” said Professor Smith.

The scope of the consequences from deep seabed mining, however, will not be well understood until a full-scale mining operation is conducted. According to the study authors, the extent of the disturbance that would be caused by continuous mining for decades cannot be simulated or effectively studied at a smaller scale.

“All the simulations conducted so far do not come close to duplicating the spatial scale, intensity and duration of full-scale mining,” said Professor Smith. 

“Further, the computer models use ecosystem sensitivities derived from shallow-water communities that experience orders of magnitude higher levels turbidity and sediment burial (mining-type perturbations) under natural conditions than the deep-sea communities targeted for mining.”

The primary target for deep seabed mining operations is in the Pacific Ocean near Hawaii and Pacific Island nations. The nations may benefit economically from deep sea mining, but will also suffer the most from any negative environmental consequences. This creates a need to understand the trade-offs of deep sea mining.

“Polymetallic-nodule mining (as currently planned) may ultimately impact 500,000 square kilometers of deep seafloor in the Pacific, an area the size of Spain, yielding perhaps the largest environmental footprint of a single extractive activity by humans,” said Professor Smith. “Addressing the misconceptions and knowledge gaps related to deep sea mining is the first step towards effective management of deep seabed mining.”

The researchers plan to work closely with regulators and society to help manage deep seabed mining. They emphasize the need to proceed slowly with seabed mining until the potential effects are fully appreciated.

The study is published in the journal Trends in Ecology and Evolution.

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By Chrissy Sexton, Earth.com Staff Writer