Deep-sea mining can be disastrous for marine animals

From a recent study published in Deep Sea Research Part I: Oceanographic Research PapersResearchers from Wageningen University & Research and the University of Bergen have shown that the release of deep-sea mining particles can have serious harmful consequences for deep-sea fauna.

The effects of mining plumes were simulated by exposing the common deep-sea sponge Geodia barretti and its associated brittle star species to a field-relevant concentration of suspended particles made from fractured massive sulfide deposits (SMS) on the seafloor. SMS deposits are large three-dimensional, geological formations on the seabed and a prime target for deep-sea mining because they contain large amounts of valuable metals.

The study revealed an alarming tenfold increase in tissue necrosis in the sponges after exposure to airborne SMS particles. All brittle stars in the experiment died within ten days of exposure, likely due to exposure to toxic metals. Concentrations of iron and copper were found to be ten times higher in SMS-exposed sponges, demonstrating the accumulation of the suspended mining particles in the tissues of these filter-feeding animals.

According to research leader and marine biologist Erik Wurz, the research results are a first wake-up call. “They underline the urgent need for comprehensive assessments of the impacts of deep-sea mining on marine ecosystems,” he says. “The adverse effects observed on Geodia barretti and related species indicate possible disruptions in benthic-pelagic coupling processes, necessitating further research and establishing guidelines for the protection of this deep-sea fauna.”

This research is important, according to Wurz, because it highlights the potential ecological risks associated with deep-sea mining activities. Recently, large areas of the deep-sea floor in the North Atlantic Ocean have been shown to be highly productive, sponge-dominated ecosystems, rather than arid deserts as commonly believed. By demonstrating the impact of mining particles on these sponge soils, the study underlines the need for sustainable management practices to mitigate the adverse effects of mining on this marine biodiversity.