You may be asking yourself this question right now as you sit on your towel, feet in the sand, and the ocean or sea as your sole horizon. We chose to investigate these water bodies, which are very popular summer destinations where we like to dive without restraint. In this article, you will finally understand the difference between sea and ocean.
Most of us landlubbers spend our lives on solid ground, so it’s easy to forget that Earth is primarily an ocean planet, with 71 percent of its surface covered in water, the majority of which connects in a massive blue mass around our little green islands. Isn’t salt water the same in the ocean and the sea? Both yes and no. The two words are frequently used interchangeably in everyday speech. However, cartographers and geographers use the terms differently, particularly when referring to specific, named bodies of water.
What is an ocean?
When people talk about the ocean, they usually mean the vast body of salt water that covers nearly three-quarters of the Earth’s surface. Consider this to be one large, unbounded body of water in which the continents are islands. We’ve divided this vast expanse—the world ocean, as it’s sometimes referred to—into sections based on the distance between continents.
Each of these sections is also referred to as an ocean, and each has its own name: the Pacific Ocean (from the east coasts of Asia and Australia to the west coasts of the Americas), the Atlantic Ocean (from the east coasts of the Americas to the west coasts of Europe and Africa), the Indian Ocean (between the east coast of Africa, the Indian subcontinent, and the west coast of Australia), and the Arctic Ocean (between the east coast of Africa, the Indian subcontinent, and the west coast of Australia) in the extreme global south. The Pacific and Atlantic are the largest, and they are further subdivided into the North Atlantic and South Atlantic, as well as the North Pacific and South Pacific. So, if you add up these divisions, you’ll get a total of seven oceans (instead of five).
Diving in the ocean on a submarine is extremely dangerous, but it provides us with crude oil and abundant natural gas. Furthermore, oceans are what divide our continents geographically.
What is a sea?
In general, when people say the sea, they frequently mean the same thing as the ocean—the vast, connected body of salt water that covers the majority of the planet. A sea, on the other hand, is a division of these waters, of considerable extent, more or less clearly marked off by land boundaries. In this sense, the distinguishing feature of a sea is that it is a portion of the ocean that is bounded by land in some way—typically smaller landmasses rather than entire continents. Among the many large and well-known seas that fit this definition are the Mediterranean Sea, the Caribbean Sea, the Arabian Sea, the South China Sea and the Red Sea.
Some bodies of water, such as the Black Sea, are completely surrounded by land but are large enough to be considered as seas. Not every body of water can be classified, and there are exceptions and outliers. The Sargasso Sea, a relatively calm section of the Atlantic Ocean, is not bounded by land and is defined instead by its location between ocean currents. Furthermore, you will find them more useful than oceans. It provides salt and regulates the earth’s climate through evaporation and condensation. Finally, all seas are oceans that eventually merge to form the oceans.
Furthermore, not every body of water with the word sea in its name is, in fact, a sea. Both the Caspian and Dead Seas are saltwater lakes. The Sea of Galilee is a freshwater body of water. There are over 50 seas on the planet. So, why are we so accustomed to hearing “seven”?
What are the seven seas?
The term “seven seas” now refers to the seven ocean divisions: the North Pacific Ocean, the South Pacific Ocean, the North Atlantic Ocean, the South Atlantic Ocean, the Indian Ocean, the Arctic Ocean, and the Antarctic Ocean. However, it has various meanings throughout the history. Many geographers and historians believe that it most commonly referred to the Indian Ocean, Black Sea, Caspian Sea, Adriatic Sea, Persian Gulf, Mediterranean Sea, and Red Sea in the ancient world. However, this was most likely different in different parts of the world where different bodies of water were known.
Difference between sea and ocean
In the broadest sense, the terms sea and ocean are frequently used interchangeably to refer to the vast body of salt water that covers the majority of the planet. For the purposes of geography, an ocean is one of the five (or seven) divisions of these waters, whereas a sea is a smaller portion of the ocean, most often bounded by land in some way. People are much more likely to refer to a specific ocean as the sea than to refer to a specific sea as the ocean.
Before the first trip around the world, the ocean was called “Ocean Sea,” but it wasn’t until Magellan was sailing the world ocean that he decided to call it “Pacific,” after noticing how calm it was. Since then, every part of the world’s ocean has been given a name: the Atlantic Ocean, the Indian Ocean, the Austral Ocean, and the Arctic Ocean. When we look at the definitions of “ocean” and “sea,” we can see that there is a very subtle difference between the two. However, there are a few characteristics that distinguish a sea from an ocean.
Size: We often hear that size doesn’t matter, but it does in the maritime industry. Indeed, it is a matter of size! The ocean’s vast surface area easily distinguishes it from the sea. Even though the sea is a large body of salt water, its surface area is smaller. For comparison, the largest sea (Arabian Sea) has a surface area of 3.6 million km2, while the smallest ocean (Artic Ocean) has a surface area of more than 14 million km2.
Borders: The distinction between sea and ocean does not end there; it is also a matter of borders! If we look at the definition of the ocean, we can see that it is always surrounded by continents. The sea can be surrounded by land or the ocean. As a result, there are various types of sea on the blue planet. A “shelf” sea is essentially an extension of the ocean. This is true of the Channel, the North Sea, and the Caribbean Sea, all of which border the Atlantic Ocean. An “enclosed” sea, like the Caspian and Aral Seas, is not connected to any other sea. The Sargasso Sea is unique in that it has no shores and is simply a zone of the Atlantic Ocean. This is why distinguishing between the sea and the ocean can be difficult at times.
Salinity: The borders and size of the water body are not the only differences between ocean and sea. Indeed, the salinity of the water is an important consideration. Surely, comparing the taste of water does not distinguish the ocean from the sea, even though the water in the oceans is less salty than that in the seas (the salinity of oceans is on average 35 g/L).
Why is sea salty?
Because of thermohaline circulation, ocean currents allow for the regulation of ocean salinity. Seas, on the other hand, are saltier due to greater water evaporation. Because salt does not evaporate, sea water has a higher sodium chloride density. For example, the salinity of Mediterranean Sea is 39 g/L, while the salinity of Red Sea is 42 g/L. The only exception to this rule is the salinity of Baltic Sea, which is 7 g/L. This low-salt water can be explained by a large amount of freshwater input and rainfall, which all compensate for the water lost due to evaporation.
Depth: Depth is another factor that distinguishes seas from oceans! In general, the ocean is much deeper than the sea, though some seas can be almost as deep as large oceans. To give you some perspective, the Channel depth is 174 m, the North Sea depth is 700 m, and the Black Sea depth is 2,212 m. Some seas are much deeper than others, such as the Mediterranean Sea, which has a depth of 5,267 meters while, the depth of Sargasso Sea is 7,000 meters, and the depth of Coral Sea is 9,140 meters.
However, oceans can reach incredible depths, often exceeding 8,000 meters, such as the depth of Indian Ocean is 8,047 meters, the Atlantic Ocean depth is 8,486 meters, or the Pacific Ocean with its Mariana Trench, which can reach 11,022 meters, the deepest seabed in an ocean ever recorded.
Aquatic plants: There are no aquatic plants in oceans because of their depths. Since they are deeper than seas, so sunlight cannot penetrate it deep enough. Thus there can be no photosynthesis. That’s why the major use of oceans is restricted for industrial purposes. However, plenty of aquatic organisms is found in seas. The use of sea is mostly commercial, like fishing industry.
Ocean Vs Sea
The list of difference between ocean and sea is given below:
- Ocean is a Water body covering 2/3rdof the surface of the earth while seas are the bodies of saltwater that surrounds its landmasses.
- Ocean has salt water but sea water is saline.
- An ocean is deeper than a sea.
- Size of an ocean is much greater than that of a sea.
- Marine life is very rare in ocean but it is very abundant is any sea.
- The largest ocean in world is Pacific Ocean while the largest sea of world is Philippine Sea.
- An ocean is not enclosed by land while a sea is partially enclosed by land.
- Oceans have industrial uses like mining for natural gas, oil, etc. on the other hand, seas have commercial uses like fishing, recreational sport activities and many more.
- Usually an ocean covers larger area than a sea.
- Common examples of oceans are Pacific Ocean, Atlantic Ocean, Indian Ocean, etc. and the examples of seas include Mediterranean Sea, Caribbean Sea, South China Sea, etc.