Sea, Types, Defining Boundaries of Seas, Zones/Layers

Sea, Types, Zones/Layers

1. Submitted by, Danish Manhas Roll No – 0940218 Semester – 4th Integrated B.Sc. (Hons) - MSc. Zoology SEA

2. CONTENT What is Sea? Types of Seas How are Sea Boundaries Defined? Some biggest Seas of the World Zones/Layers of Seas Reference Images

3. What is Sea? → Sea is a body of salt water, that is partially or totally surrounded by land. So ,a sea can be landlocked from all the sides or from most of sides.

4. Courtesy – Shubham Bharadwaj

5. TYPES OF SEAS →Broadly speaking, there are three different types of seas. They are: - 1.Almost Enclosed Seas 2.Partly Enclosed Seas 3.Hypersaline Lakes Seas

6. Almost Enclosed Seas →These are the types of Seas that reach very deep into the continents. However, they do stay connected with one or the other Ocean of the world through Straits, which are basically narrow waterways. For example - Mediterranean Sea and the Baltic Sea.

7. Partly Enclosed Seas →Partly Enclosed Seas are those types of seas that are connected to the Oceans by a very wide opening. They behave almost in the same way like the Oceans they are connected to, especially in terms of the water circulation. For example – South China Sea.

8. Hypersaline Seas/Lakes →Finally, there are types of Seas that are completely surrounded by land from every side. They are totally landlocked without any natural outlet. These are basically lakes – huge lakes. For example – The Dead Sea.

9. How are Sea Boundaries Defined? →Sea boundaries are usually defined using three parameters: 1. Landforms that lock the sea from several sides. 2. Water currents. Yes, as vague as it may sound, it is true. 3. Imaginary lines like latitudes and longitudes.

10. Some Biggest Seas of the World Mediterranean Sea – Largest Sea with total area of 1,144,800 square miles. Caribbean Sea – Second Largest Sea with total area of 1,049,500 square miles. South China Sea – Third Largest Sea with total area of 895,400 square miles. Bering Sea – Fourth Largest Sea with total area of 884,900 square miles. Gulf of Mexico – Fifth Largest Sea with total area of 615,000 square miles. Okhotsk Sea – Sixth Largest Sea with total area of 613,800 square miles.

11. Layers or zones of Sea →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. → Japan’s Marina Trench is the deepest part of the ocean ever to be explored by man, and it sits at 35,797 feet.

12. Layers or zones of Sea 1. Abyssopelagic Zone (Abyss) – The Abyssopelagic zone, also known as the Abyss or Abyssal zone It lies just above the hadalpelagic layer between 13,124 feet and 19,686 feet.

13. Layers or zones of Sea 2. Bathypelagic Zone (Midnight Zone) Lies 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. 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.

14. Layers or zones of Sea Mesopelagic Zone (Twilight Zone) Lies between 656 feet and 3281 feet just above the Abyss just above the Bathypelagic zone. Faint Sun rays penetrates this zone. The zone is home to some of the strangest sea animals like the swordfish and the wolf eel.

15. Layers or zones of Sea 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. Plenty of light and heat found here. The coral reefs can be found in the layer and the photosynthesis process occurs here.

16. Layers or zones of Sea 5. Continental Shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water known as a shelf sea. Much of these shelves has been exposed during glacial periods and interglacial periods. The shelf surrounding an island is known as an insular shelf.

17. Image Source – Google Sites

18. Image Source - Britannica

19. Thank You !