Misunderstandings of deep sea cause underestimation of impact on seabed

A new publication on the effects of deep-sea mining by 13 leading deep-sea biologists, led by University of Hawaii at Manao Oceanography Professor Craig Smith, seeks to dispel scientific misconceptions that have led to miscalculations of the likely effects of commercial operations to extract minerals from the seabed.

The deep sea, depth of the ocean below 200 feet (200 meters), accounts for more than 90% of the biosphere, contains the most external and extreme ecosystems on the planet, and supports services for biodiversity and ecosystems of global importance . Interest in deep seabed mining for copper, cobalt, zinc, manganese and other precious metals has grown strongly in recent decades and mining activities are expected to begin soon.

“As a team of deep-sea ecologists, we were alarmed by the misunderstandings that exist in the scientific literature that discuss the potential impact of seabed mining,” Smith said. “We found underestimations of mining footprints and a poor understanding of the sensitivity and biodiversity of deep ecosystems, and their potential to recover from mining impacts. All authors found it necessary to dispel misunderstandings and highlight what is known and is unknown about deep impact of seabed mining. “

In addition to the impact of mining on aquatic ecosystems above extraction activities, as detailed in another UH-led study published last month, Smith and co-authors stress the impact of deep-sea aquifers, where habitats and communities are permanent will be destroyed by mining.

The ultimate rule is that many deep-sea ecosystems will be highly sensitive to marine wall mining, likely to be affected on much larger scales than predicted by mining interests, and that local and regional biodiversity losses are likely, with potential for species “extinction,” Smith said.

However, the extent of impact on full-scale mining will not be well understood until a full-scale mining operation is carried out for years. The geographic scale and the sensitivities to the mining disturbance ecosystem that have been continuously present for decades cannot, according to the authors, be simulated or effectively studied on a smaller scale.

“All simulations performed so far do not come close to duplicating the spatial scale, intensity and duration of full-scale mining,” Smith said. “Furthermore, the computer models use ecosystem sensitivities derived from shallow water bodies that experience orders of higher levels of turbidity and sediment burial (mine-type perturbations) under natural conditions than the deep-sea mining-focused communities.”

Much of the planned deep-sea mining will be focused on the Pacific Ocean, near Hawai’i, as well as Pacific countries. Nations of Hawaii and the Pacific Islands are likely to suffer the most from negative environmental impacts, but could benefit economically from deep-sea mining, making it necessary to understand the compromises of such mining.

“Polymetallic nodule mining (as currently planned) could eventually affect 500,000 square kilometers of seaflower in the Pacific Ocean, an area the size of Spain, and perhaps the largest environmental footprint of a single extractive activity produced by humans, “said Smith. Addressing the misunderstandings and knowledge gaps related to deep-sea mining is the first step towards effective management of deep-sea mines. “

The researchers aim to work closely with regulators and society to help manage deep-sea mining and emphasize the need to gradually pursue marine practices until effects are fully appreciated.