Hi Aspirant,

Benthic zone is part of ocean layer which describes the layers closer to the bottom of the water body ,and pelagic zone is layer which includes the free water column that interacts with the surfaces layers of the water body. Physical and chemical properties of this zone vary greatly because of the vastness of this area ,which extends from the uppermost waters down to the deeper layers near the benthic zone of a water column.Organisms that live in the benthic region are coined as 'benthos', and organisms found in the pelagic zones are referred as pelagic organisms. • Referring to the open sea, benthic zone is characterized by low temperatures, low dissolved oxygen levels, low/no light, and high pressures.

Hope it helps!!