What is Pelagic Zone?
A pelagic zone is an area of a lake, river or lake that does not contact the coast or bottom. The marine organisms that live in that area are not in contact with the bottom or coast for the rest of their lives.
The pelagic zone is devoid of nutrients. Larger fish obtain their food by swimming long distances or drifting with the water and consuming nutrient-deficient organisms.
Sub-Zones of Pelagic Zone
- Epipelagic Zone
This zone extends from the surface to a depth of about 200 m.
The surface area is where enough light enters to produce photosynthesis.
This area is dominated by phytoplankton, diatoms and dinoflagellates.
Large fish such as tuna and shark can be found in this area. Therefore, small animals come to this area at night to avoid the larger animals around them.
- Mesopelagic Zone
This zone extends 200-1,000 m below the epipelagic zone.
This is known as the evening field.
Although some light reaches the area, it is not enough to produce light.
Some animals found in this area have larger eyes to make better use of low light.
The oxygen content is also very low.
Organisms such as squid, nautilus shells and swordfish have the ability to survive when oxygen is low.
Pelagic Zone Animals
Organisms in the pelagic zone range from small plankton to large mammals such as whales. Phytoplankton provide oxygen to humans and food to many animals.
Zooplankton is also found in this area. Those rare organisms are the plankton, which contains most of the microorganisms and macroorganisms.
Invertebrates such as jellyfish, squid, octopus and krill are also found in the pelagic zone.
Larger marine organisms such as crustaceans, sharks, bluefin tuna, and sea turtles live or migrate through the pelagic zone. Seabirds such as puffins, petrels and gannets can be seen above the pelagic zone.
Challenges in the Pelagic Zone
This area can be affected by wave and wind activity, pressure, presence of prey and water temperature. The pelagic zone extends over a wide area. Prey can be spread over a range of distances, and animals can travel considerable distances to locate it.
Some animals must walk miles between breeding grounds. They can change in water temperature, human activity and prey species. Thus, animals in the pelagic zone face several challenges.
