Many thousands of square kilometres of the deep-sea floor are covered by metal-bearing nodules. They contain primarily manganese, but also nickel, cobalt and copper, which makes them economically promising.

Manganese is the metal that is also found in sea beds.

Explanation:

- Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery-grey metal that is widely distributed in the Earth's crust.
- Manganese is found in various minerals, such as pyrolusite, braunite, psilomelane, and rhodochrosite. It is also found in sedimentary rocks and soils.
- Manganese is an essential trace element for living organisms, playing a role in several biological functions, including enzyme activation, metabolism, and bone development.
- Manganese nodules are found in the deep sea beds of the world's oceans. They are rounded lumps of manganese and other minerals, such as iron, cobalt, nickel, and copper, that have precipitated out of seawater over millions of years.
- These nodules are typically found at depths of 4,000 to 6,500 meters and cover vast areas of the ocean floor, particularly in the Pacific and Indian Oceans.
- While manganese nodules have been known since the late 1800s, their economic potential has been explored only in recent decades. They are a potential source of metals for various industries, including steelmaking, battery production, and electronics manufacturing.
- However, the extraction of manganese nodules poses significant environmental challenges, such as disrupting deep-sea ecosystems and releasing heavy metals into the water column. Thus, their exploitation is subject to strict regulations and environmental assessments.