The abyssal zone is the part of the ocean that is located more than 2,000 meters deep in the sea. The zone is mainly defined by its different environmental conditions which are very uniform, a characteristic that is reflected in the different forms of life that inhabit it. The abyssal kingdom is the largest environment for life on Earth, covering approximately 300,000,000 square kilometers, about 60 percent of the global surface and 83 percent of the area of oceans and seas. Abyssal waters originate at the air-sea interface in polar regions, primarily Antarctica. In these waters, salts and nutrients such as nitrogen, phosphorus and silica can be found in concentrations, and they are very uniform, even much higher than in the overlying waters. This is because abyssal waters are the reservoir of the salts of decomposed biological materials settling down from the upper zones, and the lack of sunlight prevents their absorption by photosynthesis.
The fish that inhabit the abyssal zone are known as abyssal fish. These animals tend to be gray or black, not very structured and without lines. The mobile forms have long legs; and the animals tied to the bottom have stems, allowing them to rise above the water layer closest to the bottom, where oxygen is scarce. Crustaceans and abyssal fish may be blind. With increasing depth, carnivores and scavengers become less abundant than animals that feed on mud and suspended matter.
Abyssal animals are believed to reproduce very slowly. Certainly the animals that inhabit this area are very strange and have a monstrous appearance. Most of them are also bioluminescent, which helps them attract prey and avoid certain dangers. You can also find abyssal gigantism, which includes animals as large as sea spiders that measure more than 1.50 meters. Among the species that we can find are: the giant squid that manages to measure between 17 and 19 meters long, the dragon fish, balloon fish, crystal squid, octopus Dumbo, anoplogaster brachycera, soccpharynx, melanocetus johnsonii and fish axe.
The flora that inhabits the abyssal zone feeds mainly on debris that falls to the bottom of the sea from the surface. Since sunlight cannot reach the plants they are not capable of photosynthesis, so there is no green algae. In some of the places where hydrothermal sources are present, which depend on volcanic energy, there is chemo synthesis, which develops some bacterial species.