Pelagic
Any water in a sea or lake that is not close to the bottom or near the shore can be said to be in the pelagic zone. The word pelagic means "open sea". Of all the inhabited Earth environments, the pelagic zone has the largest volume, and the greatest vertical range. Pelagic life is found throughout the water column, although the numbers of individuals and species decrease with increasing depth. The regional and vertical distributions of pelagic life are governed by the abundance of nutrients and dissolved oxygen; the presence or absence of sunlight, water temperature, salinity, and pressure; and the presence of continental or submarine topographic barriers.