Where is the deep sea?
The deep sea is classified as anything below the continental shelf, which is 200 m deep.
The seafloor beneath the deep sea can be further subcategorised into bathyal (200-4000m depth), abyssal (4000-6000m) and hadal (6000m+) zones.
Polymetallic nodules are found on abyssal plains, relatively flat areas of the ocean floor. Abyssal plains cover over 50 percent of the Earth’s surface.
The deep sea is also known as “aphotic”, meaning that there is little or no light. It is also typically food poor. Much of the deep ocean floor is covered in very fine, muddy sediment. Most of the sediment lying on the deep seafloor originates from dead and decaying marine organisms and their waste falling down the water column to rest on the deep ocean floor, which is a source of food for some of the deep ocean dwelling species.