The ocean water column is made up of five zones: the sunlight zone (epipelagic), the twilight zone (mesopelagic), the midnight zone (bathypelagic), the abyssal zone (abyssopelagic) and the hadal zone (trenches).
The abyssal zone, or the abyss, is the seafloor and water column from 3,000 to 6,500 meters (9,842 to 21,325 feet) depth, where sunlight doesn’t penetrate.
The region extending from 6,000 to 11,000 meters is called the hadal, or hadalpelagic, zone after Hades, the Greek god of the underworld. They occur only in trenches across the…
The midnight zone, or bathypelagic, extends to about 4,000 meters (about 13,100 feet), which reaches the ocean floor in many places is in perpetual darkness.
The upper layer of the ocean is known as the sunlit, or euphotic, zone. Because water strongly absorbs light, sunlight penetrates only to depths of about 200 meters (656 feet).
The ocean twilight zone is a layer of water that stretches around the globe. It lies 200 to 1,000 meters below the ocean surface, just beyond the reach of sunlight.