ABYSSAL PLAIN: CHARACTERISTICS, ELEMENTS, FLORA, FAUNA - GEOGRAPHY - 2025

The abyssal plain is the portion of the continent that sinks into the ocean and forms a surface with a tendency to be flat, which is located at depths between 2000 and 6000 meters below sea level. This portion of the continental surface is easily identifiable because its profile is close to being horizontal, unlike the underwater terrain that surrounds it.

Before reaching the abyssal plain there is an abrupt fall known as the continental slope, and after this new abrupt falls can be found: the abyssal pits or abysses.

The Gulf of Viscaya is home to an abyssal plain. Source: Satellite pictures, from NASA World Wind Globe, version 1.4

It is estimated that, together, all these gentle ocean slopes could make up 40% of the sea floor, making them the largest sediment deposits on the planet.

characteristics

The main characteristic of the abyssal plains is described in their name: like the plains on the mainland, they are almost flat. They have a slope or inclination, but this is practically imperceptible due to the vast extensions in which it develops.

These plains are produced by the constant accumulation of sediments caused by natural processes on the continent and which, in one way or another, discharge their content into the sea.

These sediments travel through the different currents and settle at different depths, covering gaps, resulting in plains that register up to 800 meters of sedimented material.

Given the great depth in which this area of ​​the ocean floor is located, sunlight cannot reach it. For this reason the temperatures are extremely low, almost reaching the freezing point.

Thanks to all these extreme conditions and due to the great pressures that can be recorded, one might think that there is not much life in that region, but that would be a mistake.

Location

Most of these abyssal plains are concentrated in the Atlantic Ocean. The Indian Ocean also has plains, but they occupy much less area compared to the Atlantic.

In the Pacific Ocean, where abrupt topographic changes predominate, it is more difficult to find them. There they are relegated to the small strips of underwater soil between abyssal accidents.

Elements

Representation of an abyssal plain (abyssal plain)

The unchanged relief, typical of the abyssal plain, is hardly disturbed by formations such as the following:

Volcanic hills

They are elements formed by the accumulation of material from underwater volcanic eruptions. This material accumulates eruption after eruption, creating a small ridge with well-defined edges and gently falling side walls.

Volcanic islands

They are nothing more than volcanic hills that, due to their constant and abundant activity, have managed to rise to the surface, even reaching several hundred meters above sea level.

Hydrothermal vents

They are strange formations through which water emanates at impressive temperatures. Despite the fact that in its immediate surroundings the water is at a temperature almost freezing (barely 2 ° C), through these vents the water can escape with temperatures that vary between 60 ° C and almost 500 ° C.

Due to the crushing pressure at these depths, the water can maintain its liquid state or become what is known as supercritical fluid. The combination of pressure and salinity concentration means that water can change its physical properties and hover between liquid and gas.

As is logical to think, this occurs from the magmatic action of the tectonic plates that make up our globe. These vents make an important contribution to dissipating the increasing pressure between plates.

Cold filtration

Although this is not a physical element as such, it is a phenomenon that only occurs in these plains and was discovered recently (1983, in the Gulf of Mexico).

It is a kind of lagoons or pools of concentration of hydrocarbons, hydrogen sulfide and methane that "float" among the deep ocean waters.

These concentrations, discovered for the first time at 3200 m depth, are perceived by the difference in density with the surrounding waters. We could imagine a drop of oil in a glass of water, but on a much larger scale.

With the slow passage of time, this concentration of substances is being decanted and degraded until it disappears.

Guyot

It is another formation whose origin could also be volcanic. In this case, it is a tubular or conical structure that seems to have managed to emerge to the surface but that was eroded over time, thus leaving its top flattened. To have a graphic image, it is worth saying that it is a volcanic island cut at the height of the sea.

Flora

At first, when the abyssal plains were discovered, they were assumed to be vast expanses of desert. The great distance that separates us from these, the vastness of the surface they occupy, and the difficulty involved in visiting them, made scientists around the world follow this line of thought for many years.

Despite the fact that a great diversity of species has been shown to make life in the abyssal plains in the last two decades, the way in which they interact and the structure of their ecosystems has not yet been studied in depth.

It must be taken into account that no sunlight reaches these immense depths, so there is no type of plant species capable of photosynthesis. In this difficult environment, it is only possible to obtain energy from the debris that falls from the surface or by chemosynthesis.

Hydrothermal vents or hydrothermal vents are the places where life is concentrated and swarms, capable of carrying out this process of converting heat, minerals and gaseous emanations into vital energy. Chemosynthesis is a process reserved for a handful of plant species that are part of the food chain at the bottom of the sea.

Fauna

Unthinkable creatures inhabit the deep sea. Currently there are between 17,000 and 20,000 known species for that strip of ocean, but if we think that only 10% of the ocean is known, it can be concluded that we are not even close to knowing all of the inhabitants of that ocean. medium deep, cold and dark.

Invertebrates such as crustaceans, snails, worms, bacteria, protozoa, and ghostly-looking fish are the inhabitants of these vast expanses. Poorly studied, it is only possible to see them in their environment with specialized equipment, underwater robots, bathyscaphs, powerful submersibles, among other mechanisms.

Something notorious among the species of the fauna of the deep ocean is bioluminescence, a phenomenon that consists in that the animal can make areas of its body shine thanks to chemical substances and body electricity. This phenomenon is recurrent and serves both for navigation and for food, luring the prey into a deadly trap.

Other characteristics present in the inhabitants of the abyssal plains are the evolution of eyes (which may have disappeared in some cases), the evolution of jaws with large and sharp teeth that project beyond the body of the animal, and the majority presence of individuals with dark or opaque skin colorations.

Differences with continental shelf

By continental shelf it defines the portion of the continent that enters the sea and begins to sink. This downward journey, starting at 0.00 asl (above sea level), can take a few meters or hundreds of kilometers.

In general, the continental shelf is taken as that submarine extension of the continent that extends until the first abrupt fall towards the depths (the continental slope). The average depth for this stretch of ocean is 200 m.

Graphic profile

If you make a graph of the ocean profile, the continental shelf would be a long beach that begins on the continent and continues and sinks into the sea. After that, it would run into a first great fall (the so-called continental slope) and after this slope a new beach or horizontal line with a small slope would begin: the abyssal plain.

So, we can say that both underwater features share similarity in profile and relief. Their main difference lies in the depth in which each of these is located, the pressure, the temperature, the light that each one receives and the biodiversity they harbor.

Bustling life

Without a doubt, life on the continental shelf is everywhere. The best known marine species, in their different shapes and sizes, adorn the landscape, share space and serve as a renewable resource for their exploitation.

Examples

Due to the rugged seabed, the distribution of the tectonic plates and the consequences of their collisions, the abyssal plains are found in unequal numbers throughout the different oceans of the planet. Below we will list the most outstanding ones taking into account the ocean of which they are part:

Atlantic Ocean

- Abyssal Plain Sohm.

- Abyssal plain of Ceará.

- Abyssal plain of Pernambuco.

- Argentine abyssal plain.

- Abyssal plain of Vizcaya.

- Cape Verde abyssal plain.

- Abyssal plain of Angola.

- Weddell Abyssal Plain.

Indian Ocean

- Abyssal Plain of Somalia.

- Abyssal Plain of Arabia.

- Abyssal Plain Perth.

- Abyssal Plain of Tasmania.

Pacific Ocean

- Abyssal Plain Tufts.

- Aleutian Abyssal Plain.

Antartic Ocean

- Abyssal Plain Bellishausen.

- Abyssal Plain Enderby.

References

1. "Abyssal Plain" in Wikipedia. Retrieved on March 1, 2019 from Wikipedia: es.wikipedia.org
2. "Abyssal Plain" in Wikipedia. Retrieved on March 1, 2019 from Wikipedia: en.wikipedia.org
3. "Abyssal Plain" in Encyclopaedia Britannica. Retrieved on March 1, 2019 from Encyclopaedia Britannica: britannica.com
4. "Abyssal Fauna" in Wikipedia. Retrieved on March 1, 2019 from Wikipedia: es.wikipedia.org
5. "Continental Shelf" in Wikipedia. Retrieved on March 1, 2019 from Wikipedia: es.wikipedia.org
6. Errázuris, A., Gangas, M., Georgudis, B., Rioseco, R. "Teaching materials for teaching geography" in Google Books. Retrieved on March 1, 2019 from Google Books: books.google.cl
7. Tarbukc, E., Lutgens, F. “Earth Sciences. 8 Edition. An introduction to physical geology ”in Ruta Geológica. Retrieved on March 1, 2019 from Ruta Geológica: rutageologica.cl
8. Ponce, J. "Submarine platform and Argentine Atlantic coast during the last 22,000 years" in Researchgate. Retrieved on March 1, 2019 from Researchgate: researchgate.net