SOURCE: The Ecologist

DATE: March 15, 2019

SNIP: It would probably surprise you to hear that there are rich, deep-sea ecosystems under threat from an emerging ocean industry… and virtually no-one knows about it.

Within the next decade, the deep-sea mining industry plans to send 300-tonne vehicles to harvest tens of thousands km2 of deep seafloor for minerals considered vital to the future of green technology. But these hard mineral resources are also home to fragile and diverse ecosystems, some new to science and some yet to be found.

Currently in its exploration phase, deep-sea mining is targeting three different types of mineral resources on the deep-ocean floor: potato-sized manganese nodules, also known as polymetallic nodules, that carpet vast areas of abyssal plains; cobalt crusts, also known as ferromanganese crusts, that form on the slopes of some undersea mountains; and seafloor massive sulfides, that form at undersea hot springs called hydrothermal vents.

The nodules are rich minerals of economic interest such as Nickel, Copper, Cobalt, Lithium and Rare Earth Elements, a group of elements vital for green technology, such as neodymium magnets for wind turbines and hybrid cars.

[A]t hydrothermal vents… hot fluids burst out of the crust, precipitating minerals to form the seafloor deposits. These can be formed subsurface, or on the seafloor where the “chimneys” of hydrothermal vents tower up to 30m tall, all enriched in minerals such as Iron, Zinc, Copper, Lead, Gold and Silver.

Both resource types provide hard surfaces for many species to attach to and create biodiversity hotspots filled with organisms often new to science. However, low food availability, cold temperatures, and low disturbance levels at nodule fields means these communities are predicted to be ill-adapted to cope with mining impacts. Scientists predict any recovery post-mining to be at decadal, if not centurial time scales.