The ocean floor (marine benthal) is subdivided into littoral (coastal zone), the neritic zone ( shelf , shallow sea, up to 200 m sea depth ), bathyal (continental slope, 200 m to 4000 m), abyssal (4000 m to 6000 m) and hadal. Bathyal, Abyssal and Hadal together form the bottom of the deep sea , to which no light can penetrate. A different definition does not include the bathyal as part of the deep sea.
The Hadal (about gr . Hades 'underworld', adjective: hadal ) the deepest areas of the ocean floor increases from about 6500 m depth one - the term is not used uniformly. The Hadal is the area of the deep sea , such as the Mariana Trench in the Pacific with a depth of over 11,000 m. The living world in this part of the deep sea is largely unexplored, but probably similar to that of the Abyssal. The organisms living here are mainly destructive , such as bacteria and crustaceans .
- Alan Jamieson: The hadal zone - life in the deepest oceans. Cambridge University Press, Cambridge 2015, ISBN 978-1-10-701674-3 .
- Jamieson 2015, p. 19 @ google books