There are four layers divided by scientists and these layers are called “Zones”
- Epipelagic Zone
- Mesopelagic zone
- Bathypelagic Zone
- Abyssopelagic zone
- Hadalpelagic zone
Epipelagic zone is the surface layer of below 200 meters (656 feet). Another name of epipelagic zone is “The SunLight Zone” because this is where most of the visible light exits. This zone receives sunlight to allow photosynthesis. This epipelagic zone divided into two zones, one is called a neuritis epipelagic zone which lies over the continental shelf and other called oceanic epipelagic zone, which is the upper layer of water that not over the continental shelf. Organisms living in the zone are plankton, floating seaweed, jellyfish, tuna, many sharks, and dolphins.
Between epipelagic and bathypelagic a zone called Mesopelagic zone, depths generally between 200m and 1,000m (656 ft and 3,280 ft). Another name for mesopelagic Zone called “The Twilight Zone”; in the warm region of the world, the temperature varies from over 20 °C (68 °F) at the top to around 4 °C (39 °F) of the boundary with the bathyal zone. Animals in mesopelagic zone are swordfish, squid, wolf eels, cuttlefish, and other semi-deep sea creatures.
Below of mesopelagic zone called Bathypelagic zone, its depth generally between 1000m and 4000m (3281 ft and 13,124 ft). The average temperature is about 39 °F (4 °C), sunlight does not reach this zone that means primary production is absent. Another name of bathypelagic is “The Midnight Zone”. Some species are present in this zone includes viperfish and frill shark, many forms nekton live in this zone such as squid, large whales and octopuses. The pressure of water in bathyal zone is nearly 5,850 pounds per square inch.
Abyssopelagic zone lies between the bathypelagic and hadalpelagic, its depth generally between 4000 meters and 6000 meters (13,124 ft and 19,686 ft). Another name for abyssopelagic Zone is “The Abyss”, this zone remains in perpetual darkness and never receives daylight. Average temperature is around 2 °C to 3 °C (35 °F to 37 °F) through the large majority of its mass. This zone is generally noted for its lack of nutrients, lack of sun light. Very few creatures can be found at these crushing depths such as Black swallower, Tripod fish, Deep-sea anglerfish and Giant squid.
Final layer called Hadalpelagic zone, also known as “The Trenches”, its depth extends from 6000 meters (19,686 ft) to the bottom of the deepest parts of the ocean. The temperature is the same as abyssopelagic zone, but the pressure is eight tons per square inch (nearly, weight of 48 blue whales). Although high in pressure and cold temperature, creatures can still live here such as starfish and tube worms.