Question

Define the benthic zone.

Answer 1

Hint: This zone is present below the pelagic zone. It is the ecological region at the lowermost level of the water body like river, lake, ocean. Simply, it is the bottom of the lake or sea floor where there is a deposition of sediments. It is an aphotic zone characterized by low temperature and low sunlight.

Complete answer: Ocean is a marine ecosystem. It is divided into 4 major regions or zones: the intertidal, neritic, oceanic and abyssal. Abyssal plain is the area where there is the presence of deep-sea coral, whale falls, etc. The abyssal zone is the layer of the pelagic zone. The pelagic zone is present above the benthic zone. The benthic zone is the lowest zone of the aquatic ecosystem like lake, river, ocean. The organisms that live in this zone are known as benthos. Benthos lives deep inside the sea where there is an absence of sunlight or aphotic zone. They feed on the detritus of another animal which lives above this zone. There is a high pressure and a low level of oxygen in the benthic region. Benthos are adapted in such a way that they can tolerate the high pressure even if they cannot survive in the low-pressure area or above zones to benthic.

Note: Animals like sea anemones, sponges, corals, sea stars, sea urchins, worms, bivalves, crabs live in the benthic region which is known as benthos. They are benthic invertebrates, which means these animals lack a backbone. Benthos lives in close relationship with the substrate and even some become attached to the bottom permanently.