【How-to】Is the viperfish bioluminescence - Howto.org

The abyssal zone or abyssopelagic zone is a layer of the pelagic zone of the ocean. “Abyss” derives from the Greek word ἄβυσσος, meaning bottomless. At depths of 4,000 to 6,000 metres (13,000 to 20,000 ft), this zone remains in perpetual darkness. It covers 83% of the total area of the ocean and 60% of Earth’s surface.