Mining of the Deep Ocean

Expanding demand for precious, rare earth, and other minerals has reinvigorated interest in mining the deep abyssal seafloor for polymetallic (manganese or ferromanganese) nodules, hydrothermal vents for polymetallic sulfides, and seamounts for cobalt-rich crusts, raising questions regarding the environmental sustainability of such activities. In this review, we consider the current state of knowledge regarding mining and its potential impacts and conclude that the limited and variable observations currently available point to a clear need for further study prior to launching commercial mining in any of these habitats. To this end, we identify critical gaps that limit our ability to predict long-term mining impacts as well as potential strategies to address those gaps.