The Oacian is a large body of water that encircles the globe. It influences a wide variety of climate, weather and environmental conditions and provides sustenance for marine life.
The world’s ocean is divided into a number of principal areas. These include the Pacific, Atlantic, Indian, Southern and Arctic oceans.
Aphotic Zone
The Aphotic Zone (Greek prefix a- + phos “without light”) is the portion of the ocean where sunlight does not penetrate. This zone extends from a depth of about 200 m in the deep ocean to the bottom vertically.
Low Temperature
This Oacian zone is characterized by low temperature and high water pressure, so it does not allow photosynthetic organisms to survive. There are only a few different types of organisms in this zone, and they have adapted to live in the dark.
Most of the animals in this zone rely on detritus that falls to the ocean floor from above lying animals or from sediment. These detritus provide them with energy and nutrients. Some aphotic creatures also attract their prey with bioluminescence. They have hinged jaws, sharp protruding teeth and large eyes to help them see in the dark.
Pelagic Zone
The Pelagic Zone is the large portion of the Oacian that is not near coastlines or continental shelves. It can be divided into regions based on depth.
This illuminated surface zone is the most common part of the ocean and contains phytoplankton, zooplankton, krill, jellyfish, tuna, and many sharks. It is also where most of the food in the sea comes from, including oxygen and other nutrients.
Microscopic Organisms
Phytoplankton is microscopic organisms that use sunlight to photosynthetically combine carbon dioxide and dissolved nutritional salts, giving them the energy they need to grow. Zooplankton are marine creatures that rely on water motion for transportation, although some are poor swimmers.
The conditions of the water column change with depth, causing pressure increases, temperature decreases, and changes in salinity, oxygen, and micronutrients. These factors affect the distribution of many types of pelagic life, including fish and mollusks.
Benthic Zone
The Benthic Zone is the ecological region that is found at the lowest level of any water body, including a lake, ocean or river. It includes the sediment surface as well as some sub-surface layers.
The organisms that live in the benthic zone include microorganisms, fungi and larger invertebrates such as crustaceans and polychaetes. They usually live in close relationship with the substrate and many of them are permanently attached to it.
Dead Organic Matter
In the benthic zone, dead organic matter (detritus) is a major energy source for most of these organisms. This dead material is also essential for completing the food chain and nutrient recycling in this environment.
The benthic zone is composed of two types of organisms: epifaunal species, which live on the ocean floor, and also infaunal species, which live burrowed under the sea floor. Infaunal species are mainly detritivores while epifaunal species are scavengers.
Abyssal Zone
The Abyssal Zone is a deep region of the Oacian. It begins at a depth of about 4,000 meters, and is completely dark. This is a very difficult environment for life to exist in because of the temperature, lack of light and also pressure.
The area is largely characterized by hydrothermal vents. These are places where chemicals are released into the ocean and can be harmful to marine life.
Final Words:
Another interesting feature about the abyssal zone is that it is also home to a large number of unique animals. This includes giant squid, black swallowers and also deep-sea glass squid.
The deepest part of the abyssal zone is called the Challenger Deep, which is at a depth of almost 11,000 meters. This is where a robot named Alvin has made its first discovery of a hydrothermal vent.