hadal zone; hadopelagic zone; trench zone
Oceanographic term for the deepest region of the ocean, below about 6,000 meters, typically in deep-sea trenches. Compare with 漸深海帯 (bathyal zone).
See also: 漸深海帯
The hadal zone refers to ocean areas deeper than 6,000 meters.
Organisms living in the hadal zone are adapted to extreme environments.
漸深海帯 (bathyal zone) is the zone above the hadal zone, roughly 200–3,000 meters deep, while 超深海帯 is the deepest zone below 6,000 meters.
Compound of 超 (chō, 'super-') + 深海 (shinkai, 'deep sea') + 帯 (tai, 'zone'). A modern scientific term formed from Sino-Japanese elements.