1.1.2 Sea bed

1.1.2 Sea bed

The sea bed is not smooth, it has different parts. We have very less information about the part of the seabed. This is because it is highly difficult to study or go deep into the sea. The deep sea provides many challenges to human such as powerful creatures, immense pressure and dark conditions etc.

The earth structure in the sea bed basically contains

  1. Continental shelf
  2. Abyssal plain
  3. Ocean ridge/submarine ridge
  4. Ocean trench
  5. Volcanic islands

Continental shelf: this is the first part in sea bed. This part is surrounded by shallow water up to 200m. In this area waves are high, so the limnotic layer breaks so oxygen enters into the water easily, so in this place more oxygen is available so alkalinity is high. In this place food availability is high this is because plankton growth is high. Plankton grow more in the place where sunlight availability is high. Because more food is available the fish availability is high in this area.

            Continental shelf provides 80% of worlds fish catch. This area provides 25% of natural fuel to the world. This area is rich in some metals and ornamental stones


ABYSSAL PLAIN: It is also called as abyssal shelf. The abyssal shelf is deep sometimes it extends to 1400 m. This area has two regions, one is LIGHT AREA, and another one is dark area.

            The light area is up to 200m, this area support green Plankton (phytoplankton) because this area contains light. The zooplankton, during the day time, to escape from sunlight or from UV light they migrate to deep waters (vertical migration), during the night time to get easy food the zooplankton move to surface.

            The dark area is the shelter for many predatory fish, because they can hide and attack the fish which usually swim in light area. The fish which live in dark area sometimes release light (bioluminescence). This light attract the opposite sex or food. The fish which live near to the bottom of the dark area age called as benthic organisms.


OCEAN RIDGE: This is the third area in seabed. This area usually forms when two plates suddenly moves away because of tectonic movements, the lava or magma or mantle rushes out, this cools rapidly because of water. This ridge before cools absorbs lot of minerals. If the light touches the bottom of the ridge, it will become the home for corals. The Maldives lie on CHARGOS LACADIVES RIDGE.

OCEAN TRENCH: This is the fourth part of the seabed. This part forms when two plates push each other. If two plates move down (same force) or if one plate moves upside and another plates moves down (subduction) the ocean trench forms. This is the most challenging area for the scientists. The deepest trench is MARIANA in Pacific Ocean, the Indian Ocean has deepest trench (sunda trench) of 8000m.

VOLCANIC ISLANDS: this is the fifth part in seabed. This part forms because when two plates push each other. This part supports lot of marine organisms deep inside the sea and support lot of plant and animals above the sea. Some times when it burst the lava flows out.


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