Editing Class O (section)

==Description==
The on average pelagic zone occupies 1,370 million cubic kilometres (330 million cubic miles) and has a vertical range up to 11 kilometres (6.8 miles). animals that live in the pelagic zone are called pelagic life. Pelagic life decreases with increasing depth. It is affected by light levels, pressure, temperature, salinity, the supply of dissolved oxygen and nutrients, and the submarine topography.

In deep water the pelagic zone is sometimes called the open-ocean zone and can be contrasted with water that is near a coast or on a continental shelf. However in other contexts, coastal water that is not near the bottom is still said to be in the pelagic zone.

The pelagic zone can be contrasted with the benthic and demersal zones at the bottom of the sea. The benthic zone is the ecological region at the very bottom of the sea. It includes the sediment surface and some sub-surface layers. Marine organisms living in this zone are called benthos. The demersal zone is just above the benthic zone. It can be significantly affected by the seabed and the life that lives there. Animals that live in the demersal zone are called demersal life.