Pelagic zone: what is, layers, flora and fauna

The pelagic area or Piélago (From the Greek “open sea”) refers to the water column on the seabed. Understand from the surface to depths of approximately 10,000 metersmanifesting different conditions as depth increases: greater pressure, lower degree of temperature, luminosity and oxygen concentration, in addition to variations in the concentration of salts and nutrients such as iron, calcium and magnesium. The pelagic zone excludes the waters that are on continental platforms, that is, the coastal or intermareal area and the neritics.

The pelagic zone is subdivided into five vertical regions that have different characteristics, including:

• Epipelagic zone: It extends from the sea surface to 200 meters deep. It is the area where sunlight penetrates, allowing photosynthesis.
• Mesopegic area: It covers from 200 to 1000 meters deep. At this level the Afigic zone begins and although the solar rays still penetrate, the light is lost with the increase in depth, preventing the photosynthetic process.
• Batipelagic area: Also known as the Batial Zone, it contemplates from 1000 to 4000 meters deep. In this region there is no longer sunlight, with the exception of the presence of bioluminescent organisms. In addition, the hydrostatic pressure increases, the low temperature (it is on average of 4 ° C) and decreases the concentration of dissolved oxygen. In this link you have more information about the battery zone: what is, flora and fauna.
• ABISOPELÁGICA: The abyssal zone extends from 4000 to 6000 meters and in it, darkness is total. The temperature ranges between 2 and 3 ° C. There is no oxygen but high concentrations of nutrients such as nitrogen, phosphorus and silica, which occur as a result of the decomposition of organic matter of upper layers. We encourage you to read this other post about the abyssal plains: what are and characteristics.
• Hadopelagic area: The Hadal zone reaches up to 11,000 meters deep and is represented by marine graves. The deepest is the “Mariana pit”, located in the Western Pacific Ocean. Here you can read more about the Hadal area: what is, flora and fauna.

Although the flora is a concept that strictly includes the variety of native or exotic vascular plants, we will make an exception in this section and we will include organisms such as algae and dinoflagellated (protists) and cyanobacteria (bacteria), that is, organisms that inhabit this oceanic zone and that are not animals. The flora of the pelagic area is abundant in upper layers (epipelagic zone) due to the availability of sunlight that allows the photosynthetic process. Its main components are:

• Phytoplankton: Includes microalgae such as diatoms, dinoflagellated and cyanobacteria. These organisms are the main primary producers in this layer. In this other post we tell you more about what phytoplankton is.
• Floating macroalgas: In areas close to the coast and depths as far as sunlight penetrates, macroalgas can be found. Some such as red algae or rodophytes (Rhodophyta edge) can be found 100 meters deep, and in exceptional cases they can reach 250 kilometers. These species currently belong to the Plantae kingdom. Here you can see more information about the macroalgas: what are, types and examples.
• Sea grasslands: Sea meadows are underwater ecosystems that are formed by angiosperm plants. Today about 66 species classified in 4 families are recognized. Some are exclusively marine such as species belonging to Zosteraceae families, Posidoniaceae, Cymodoceaceae. In this link we give you more information about sea grasslands: what are, characteristics and animals.

In the rest of the sub -levels of the pelagic zone, the luminosity decreases considerably and, therefore, photosynthesis is not possible and life is mainly based on the decomposition of organic matter of higher levels.

The organisms that inhabit in this area are known as pelagic species and usually group into different categories:

Necton

Set of organisms, generally of large size, which actively swim in the oceans and seas. They have certain mechanisms that allow them to move with intentional movements and counteract strong currents. They inhabit the water column in the first meters deep and are independent of the bottom and although they can remain close to the depths at some point, the rest of the day they move continuously. Some common species are:

• Crustaceans, like crabs.
• Cephalopods, like squid and octopus.
• Bone fish, like Atunes, sardines and salmon.
• Cartilaginous fish, like Sharks and stripes. Here you can learn more about pelagic fish: what are, characteristics and examples.
• Marine reptiles, such as sea ​​turtles.
• Sirenians, like Dugongos and Manatis.
• Pinnípedos, like MORSAS, LOBOS AND MARINE ELEPHANTS.
• Cetaceans, like whales, orcs and dolphins. Here you can learn more about what are the marine mammals animals.

Plankton

Formed by small or microscopic organisms that are located at the base of the trophic chain and cannot overcome marine currents and are usually dragged by them. Some autotrophic species of microalgae, such as diatoms and dinoflagellates, cyanobacteria and other organisms, constitute “plant” phytoplankton or plankton; others like protozoa, mini crustaceans, sponge larvae, molluscs or echinodermsthey constitute the Zooplankton o Animal plankton, which unlike phytoplankton feed on decomposition organic matter.

Here you can expand this information on what plankton is and its importance and what is zooplankton.

Marine depth animals

Beyond the Mesopegic area, animal life is reduced but exists. Some organisms of the rarest inhabit these depths into extreme conditions, for example:

• Cephalopods, like Dumbo octopuses (Grimpoteuthis genus) and Giant squid (Architeuthis Gender).
• Fish, like him hook fish (Ceratiidae family), el flashlight fish (Myctophum punctatum) and Caracol de las Marianas fish (Pseudoliparis swirei)
• Giant tube worms (Riftia Pachyptila)
• Sea spiders (PycnoGonida)

You have already learned all this about what the pelagic area, its layers, flora and fauna is, so we now encourage you to learn about the difference between sea and ocean.

If you want to read more articles similar to Pelagic zone: what is, layers, flora and faunawe recommend that you enter our category of ecosystems.