Pelagic Zone

The ecological domain known as the pelagic zone encompasses the whole water column of an ocean. The pelagic zone has the greatest vertical range of any of the inhabited environments on Earth, with a difference of 11,000 metres between the highest and lowest points. Its volume is 1,370,000,000 cubic kilometres (330,000,000 cubic miles) (36,000 feet). Pelagic life can be found at any level in the water column; but, as the depth increases, the number of people and species in the community will decrease. The availability of nutrients and dissolved oxygen, the existence or lack of sunshine, temperature of the water, salinity, and pressure, and the presence of continental or underwater topographic barriers all have a role in the regional as well as vertical distributions of pelagic life.

Pelagic zone

In a body of water like lakes, rivers, or oceans, the area that is not connected to the bottom or the coast is known as the pelagic zone. Pelagic zone inhabitants spend their entire lives above the water’s surface, meaning they never make contact with either the sea floor or the coast. The pelagic zone has a low concentration of nutrients. The giant fish must travel great distances or float with the currents in order to reach the nutrient-poor species that they must consume in order to satisfy their appetites.There are three distinct groups that make up pelagic life. The phytoplankton are tiny microbes just in the sunlit topmost layer of the ocean. They use the light from the sun to perform the photosynthetic process of combining carbon dioxide as well as submerged nutrient salts. Phytoplankton are the primary source of nutrition for all marine animals. Although some species of zooplankton, like jellyfish, are poor swimmers, they are collectively referred to as marine invertebrates that are mostly dependent on the velocity of water for transportation. To survive, zooplankton feed on phytoplankton and other, smaller forms of zooplankton. Copepods and euphausiids, which are both types of small crustaceans, make up the majority of zooplankton. The skeletal as well as cartilaginous fishes, molluscs, the decapods, as well as the rarer mammalian species, predominate among the nekton, which are the free-swimming organisms.

Water column of the open ocean

The term “water column” comes from the field of oceanography which is applied to refer to a theory which is used to describe physical (temperature, salinity, light penetration) as well as chemical (pH, dissolved oxygen, nutrient salts) features of seawater at various depths for a particular geographical location. The water column, which begins at the ocean’s surface & extends to its depths, can go as far down as 11 kilometres (Mariana trench in the Pacific). The dispersion of living things in the ocean is determined by its physicochemical properties. At shallow depths, photosynthesis is powered by sunshine; however, as we descend deeper, the environment gets more gloomy and the temperature drops by two degrees Celsius. Here, the only organisms that have a chance of surviving and flourishing are those that are able to withstand an increase in pressure of 1 bar for every 10 metres.

Not only can the physical and chemical properties of one ocean differ from those of another, but they can also be affected differently by various forces, such as the direction and strength of horizontal and vertical currents, as well as the influence of external factors, which can result in chemical anomalies. 

Surface of the sea and the bottom

The ocean has been broken down by researchers into five primary layers. These layers, which are collectively referred to as “zones,” span from the surface to the deepest parts of the ocean, where light is no longer able to reach. Some of the strangest and most fascinating species in the ocean can be discovered at the depths of the ocean where it is quite dark. The temperature is dropping, and the pressure is rising at an incredible rate as we travel further into these mainly uncharted locations.

Epipelagic zone-The epipelagic zone is the name given to the uppermost layer of the ocean, which stretches from the surface down to a depth of around 200 metres (656 feet). Because the majority of the visible light is concentrated in this region, it is sometimes referred to as the sunlight zone. Heat is produced when light is used. The vast temperature range that can be experienced in this zone can be attributed to the heat that is there.

Hadalpelagic zone-The layer begins at a depth of 6,000 metres (19,686 feet) and continues all the way down to the ocean floor. It is referred to as the hadalpelagic zone. The majority of the time, you can find these regions in canyons or deep water trenches. The Mariana Trench, which is located off the coast of Japan, is home to the ocean’s deepest point, which measures in at 35,797 feet (10,911 metres). The pressure in the water is an astonishing eight tonnes per square inch, and the water temperature is only a few degrees above freezing. That is roughly equivalent to the weight of forty-eight Boeing 747 jets. Even if the temperature and pressure are extreme, it is nevertheless possible to find life here. At these depths, it is possible for some types of invertebrates, such starfish and tube worms, to flourish.

Conclusion

The pelagic zone has the greatest vertical range of any of the inhabited environments on Earth.The activity of the waves and winds in this zone, as well as the pressure, the abundance of prey, and the temperature of the water, may have an effect on the species that live here. The pelagic zone encompasses a large geographical region. It is possible that the prey is dispersed over a certain region, and the animals may have to go a great distance in order to find it.It can be a long journey for certain animals to get from their breeding grounds to their feeding areas. They experience shifts in the temperature of the water, human impacts, and the kinds of prey available to them. As a result, the species that live in the pelagic zone suffer a number of difficulties.Understanding the connections between living creatures and environmental factors, large-scale water circulation, and the movement of matter between water masses can be gained through the study of the water column, which also contributes to this understanding.