![Depending on how deep the sea is, there can be up to five vertical layers in the ocean. From the top down, they are:
Epipelagic (sunlit)From the surface down to around 200 m (656 ft).
The illuminated surface zone where there is enough light for photosynthesis. Any water in the sea that is not close to the bottom is in the pelagic zone. The word pelagic comes from the Greek πέλαγος or pélagos, which means open sea. Due to this, plants and animals are largely concentrated in this zone. Nearly all primary production in the ocean occurs here. This layer is the domain of fish such as tuna, many sharks, dolphin fish, and jellyfish. This zone is also known as the surface zone.
Mesopelagic (twilight)From 200 m down to around 1,000 m (3,280 ft).
Although some light penetrates this deep, it is insufficient for photosynthesis. The name stems from Greek μέσον, middle. At about 500 m the water becomes depleted of oxygen. Still, an abundance of life copes with more efficient gills or minimal movement. Animals such as swordfish, squids, wolffish, a few species of cuttlefish, and other semi-deep-sea creatures live here. Many bioluminescent organisms live in this zone. Due to the relative lack of nutritious food found in this zone, some creatures living in the mesopelagic zone will rise to the epipelagic zone at night in order to feed.Bathypelagic (midnight)From 1,000 m down to around 4,000 m (13,123 ft).
By this depth the ocean is pitch black, apart from the occasional thermoluminescent organism, such as lanternfish. There are no living plants, and most animals survive by consuming the snow of detritus falling from the zones above or (like the marine hatchetfish) by preying upon others. Giant squid (as well as smaller squids & Dumbo octopodes) live at this depth, and here they are hunted by deep-diving sperm whales. From Greek βαθύς (bathýs), deep.Abyssopelagic (lower midnight)From 4,000 m down to above the ocean floor.
The name is derived from the Greek ἄβυσσος (ábyssos), abyss, meaning bottomless (a holdover from the times when the deep ocean was believed to be bottomless). Very few creatures are sufficiently adapted to survive in the freezing temperatures and incredible pressures found at this depth. Among the species found in this zone are several species of squid; echinoderms including the basket star, swimming cucumber, and the sea pig; and crustaceans including the sea spider. Many of the species living at these depths have evolved to be transparent and eyeless as a result of the total lack of light in this zone.HadopelagicThe deep water in ocean trenches.
The name is derived from the Greek Ἁΐδης (Haidēs), Hades, the classical Greek underworld. This zone is mostly unknown, and very few species are known to live here (in the open areas). However, many organisms live in hydrothermal vents in this and other zones. Some define the hadopelagic as waters below 6,000 m (19,685 ft), whether in a trench or not.Merry [early] Christmas! This is the Spirobranchus giganteus, or Christmas Tree Worm. The name “refer[s] to the two, chromatically-hued spiral structures that are most commonly what is seen of the worm by divers. In actuality, these multicolored spirals are merely the worm’s highly-derived respiratory structures.” And the crown part of the tree is it’s mouth. :-D Now I want to be an oceanographer.](http://25.media.tumblr.com/tumblr_ktk7bkNHlG1qznomdo1_400.png)
Depending on how deep the sea is, there can be up to five vertical layers in the ocean. From the top down, they are:
Epipelagic (sunlit)
From the surface down to around 200 m (656 ft).
The illuminated surface zone where there is enough light for photosynthesis. Any water in the sea that is not close to the bottom is in the pelagic zone. The word pelagic comes from the Greek πέλαγος or pélagos, which means open sea. Due to this, plants and animals are largely concentrated in this zone. Nearly all primary production in the ocean occurs here. This layer is the domain of fish such as tuna, many sharks, dolphin fish, and jellyfish. This zone is also known as the surface zone.
Mesopelagic (twilight)
From 200 m down to around 1,000 m (3,280 ft).
Although some light penetrates this deep, it is insufficient for photosynthesis. The name stems from Greek μέσον, middle. At about 500 m the water becomes depleted of oxygen. Still, an abundance of life copes with more efficient gills or minimal movement. Animals such as swordfish, squids, wolffish, a few species of cuttlefish, and other semi-deep-sea creatures live here. Many bioluminescent organisms live in this zone. Due to the relative lack of nutritious food found in this zone, some creatures living in the mesopelagic zone will rise to the epipelagic zone at night in order to feed.
Bathypelagic (midnight)
From 1,000 m down to around 4,000 m (13,123 ft).
By this depth the ocean is pitch black, apart from the occasional thermoluminescent organism, such as lanternfish. There are no living plants, and most animals survive by consuming the snow of detritus falling from the zones above or (like the marine hatchetfish) by preying upon others. Giant squid (as well as smaller squids & Dumbo octopodes) live at this depth, and here they are hunted by deep-diving sperm whales. From Greek βαθύς (bathýs), deep.
Abyssopelagic (lower midnight)
From 4,000 m down to above the ocean floor.
The name is derived from the Greek ἄβυσσος (ábyssos), abyss, meaning bottomless (a holdover from the times when the deep ocean was believed to be bottomless). Very few creatures are sufficiently adapted to survive in the freezing temperatures and incredible pressures found at this depth. Among the species found in this zone are several species of squid; echinoderms including the basket star, swimming cucumber, and the sea pig; and crustaceans including the sea spider. Many of the species living at these depths have evolved to be transparent and eyeless as a result of the total lack of light in this zone.
Hadopelagic
The deep water in ocean trenches.
The name is derived from the Greek Ἁΐδης (Haidēs), Hades, the classical Greek underworld. This zone is mostly unknown, and very few species are known to live here (in the open areas). However, many organisms live in hydrothermal vents in this and other zones. Some define the hadopelagic as waters below 6,000 m (19,685 ft), whether in a trench or not.
Merry [early] Christmas! This is the Spirobranchus giganteus, or Christmas Tree Worm. The name “refer[s] to the two, chromatically-hued spiral structures that are most commonly what is seen of the worm by divers. In actuality, these multicolored spirals are merely the worm’s highly-derived respiratory structures.” And the crown part of the tree is it’s mouth. :-D Now I want to be an oceanographer.
