Marine Biology

Benthic realm

The term benthic, a  means the  bottom  ranging from the deepest parts of the ocean to the tide  influenced areas. The most productive region of the benthic zone is the area over the continental margin, which is unaffected by the tides. Many groups and varieties of animals live here, a few are worms, sea pens, crustaceans, stars, and protozoa. The life in this zone is mostly made up of bottom dwellers which get most of their food from dead and decaying organisms. Therefore most of the organisms in the benthic zone are scavengers because they depend on dead flesh as their main food source.

  The benthic environment is further divided based on depth  into five zones as  given below.

A cross section of the ocean, from the shore line to the deepsea, showing the location of major habitats.  

i.     Intertidal zone – the area between the lowest low tide and highest high tide markings, it is sometimes called the littoral zone.

ii.    Sublittoral zone – from the lowest low tide mark to the shelf break, about 200 m deep. This area essentially coincides with the continental shelf.

iii.   Bathyal zone – from the shelf break to 4000 m. This area coincides with the continental slope and rise.

iv.  Abyssal zone – from 4000 to 6000 m. This includes the average depth of the deep ocean floor.

v.   Hadal zone – sea floor deeper than 6000 m. This includes the trenches, the deepest part of the sea floor.