• What is an abyssal plain?
• Characteristics of the abyssal plains
• Life on the abyssal plain
• Examples of abyssal plains

We explain what an abyssal plain in an ocean is, what living beings inhabit it and other characteristics. Also, examples from around the world.

In the abyssal plains the lack of sunlight makes the development of organisms more difficult.

What is an abyssal plain?

In geology and oceanography, it is known as abyssal plain to certain flat extensions of land that are at the bottom of the seas Y oceans, in the underwater region known as the abyssal zone (from the Latin abyssus, "abyss"). This is the deepest and darkest region of the known seas, where the least amount of sunlight and therefore the life it is scarce, arduous and different from the superficial regions.

However, abyssal plains are different from deep ocean depressions (such as trenches) in that they are flat, submerged land extensions close to continental extensions. They are usually found at depths of several kilometers below the surface and spread out over vast dimensions.

The geological study of these plains reveals that they have a sedimentary origin, that is, they are the result of the accumulation of sediments and substrates from the continents nearby, which accumulate over thousands or millions of years to smooth and standardize the underwater terrain. Some abyssal plains are composed of up to a kilometer of sediment accumulated and densified in this way.

Characteristics of the abyssal plains

The abyssal plains are characterized by the following:

• They are flat extensions of underwater terrain, located between 3,000 and 6,000 meters below the sea surface, and in the vicinity of the continental shelf.
• They can be extremely extensive, stretching hundreds of kilometers wide and thousands of kilometers long.
• They are usually irregular in shape, but elongated according to the margins of the continental shelf.
• They consist of an abundant sedimentary layer installed on the oceanic crust, generally composed of magnesium silicates (basalt), the result of underwater volcanic eruptions, or the accumulation of materials from the continental shelf and the surface.
• They are regions of little or no luminosity, given the absence of sunlight, and therefore devoid of photosynthetic organisms. Life down there is very different than on the surface.
• They are much more common in the Atlantic Ocean, less common in the Indian Ocean, and quite rare in the Pacific. In total, they represent 70% of the ocean floor.

Life on the abyssal plain

Deep-sea fish use light to attract their prey.

Life in the abyssal plain is adapted to the enormous pressures resulting from the mass of Water that separates it from the surface, as well as the lack of sunlight that makes it impossible to photosynthesis. In addition, temperatures are particularly low, so that the metabolisms Vitals tend to be slow and patient.

Much of life in this region is microscopic, made by bacteria autotrophs that survive through chemosynthesis, taking advantage of the resources that seismic activity releases on the seabed. There are also small crustaceans, worms and organisms simple life, many of which survive thanks to the rain of organic material (waste) that comes from the surface regions.

However, the abyssal plain is often interrupted by occasional hills and elevations (such as mid-ocean ridges), and in these places life flourishes more than in its surroundings, although it does so in ecosystems dark, deep, and poorly productive, at least compared to those on the surface.

As for the abyssal fish, they are characterized by a solitary way of life, adapted to extreme conditions. They have a long, slender body with large jaws that facilitate the capture of the occasional prey.

It is a fauna little abundant and of terrifying features. Many of them are endowed with bioluminescence (that is, the ability to generate light), but not to illuminate their path, since most do not depend too much on sight, but as a way to attract their prey.

Examples of abyssal plains

Among the main known abyssal plains, the following stand out:

• The Argentine abyssal plain, located in the deepest region of the Argentine basin, about 6212 meters below sea level and barely 800 km from the Falkland Islands.
• The abyssal plain of Vizcaya, located deep in the gulf from Vizcaya, off the Spanish coasts of Cantabria, Asturias, Galicia and the Basque Country. This plain is about 2,789 meters deep, separating the two continental shelves of the gulf.
• The Somali abyssal plain, part of the so-called Somali basin in the Indian Ocean, east of Africa. His relief is interrupted by several moutains submarines, which reach the surface forming the islands of the Aldabra group in the Seychelles.
• The Aleut Abyssal Plains, located in the Aleut Basin in the Bering Sea of ​​the Pacific Ocean, about 3,900 meters below the surface. The region is characterized by deep depressions (trenches) and enormous seismic activity.
• The abyssal plain of Bellingshausen, located in the Antarctic Ocean, south of the final coasts of Chile and close to the Antarctica, is a plain that runs along the continental shelf of the latter, and whose name honors the Russian admiral Fabián Gottlieb von Bellingshausen, who explored the area in the 19th century.