Environment

The 5 Layers of the Ocean

The ocean may be mysterious, but science has taken us far enough to be able to pinpoint five layers that exist within it.

The ocean has 5 different and distinct layers that each have their own unique characteristics. The layers range from the surface layer where most ocean activities occur, to the deep dark depths of the water that have yet to be fully explored. The deep layers have unique sea creatures, freezing temperatures, and high pressure. With the advancement in technology, scientists are hopeful that the oceanic depths will be explored thoroughly. As the depth increases, the temperature, light, and sea life decreases. Below is a summary of the ocean's 5 layers.

5. Hadalpelagic Zone (The Trenches)

The Hadalpelagic zone is also called the Trenches and is found from the ocean basin and below. The Hadalpelagic zone lies between 19,686 feet to 36,100 feet. The depth depends on the trenches and valleys in the area. Japan’s Marina Trench is the deepest part of the ocean ever to be explored by man, and it sits at 35,797 feet. In Puerto Rico, fish were discovered at 27,460 feet deep. The zone cannot be explored without specialized kits due to its cold temperatures and high pressure. Natural light cannot penetrate to the Trenches. Different creatures can be found in this layer, mostly invertebrates including starfish.

4. Abyssopelagic Zone (Abyss)

The Abyssopelagic zone, also known as the Abyss or Abyssal zone, lies just above the hadalpelagic layer between 13,124 feet and 19,686 feet. The layer’s name has origins in the Greek language and loosely translates to “no bottom.” Just like the layer below it, temperatures are near freezing point, and there is no penetration of natural light. Pressure is also high due to the weight of the water above. Invertebrates like sea stars and squids can survive in this environment. Over 75% of the ocean floor lies can be found within this zone with the continental rise starting here.

3. Bathypelagic Zone (Midnight Zone)

The Bathypelagic layer is found between 3,281 feet and 12,124 feet just above the Abyss. This layer is also called the midnight or the dark zone. Although the Bathypelagic zone is dark, visible light may be observed from sea creatures found here. The pressure in the zone reaches 5,858 lbs for every square inch, and a huge number of different sea species are found in the layer. Many animals in this layer are either black or red thanks to low sunlight penetration. Some whale species, like the sperm whale, spend some time at this level in search of food.

2. Mesopelagic Zone (Twilight Zone)

Above the Bathypelagic zone lies the Mesopelagic layer (Twilight or midwater zone). The Mesopelagic zone lies between 656 feet and 3,281 feet. The zone is home to some of the strangest sea animals like the swordfish and the wolf eel. Faint sun rays penetrate the layer.

1. Epipelagic Zone (Sunlight Zone)

The Epipelagic zone is known as the surface layer or the sunlight zone of the ocean ranging from the surface to 656 feet. There is plenty of light and heat within this layer although both decrease as the depth increases. Pressure is also minimal and increases with depth. Most oceanic life and human activities like leisure, fishing, and sea transport occur in the Epipelagic zone. The coral reefs can be found in the layer and the photosynthesis process occurs here.

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