Difference Between Ocean and Sea

Difference between Ocean and Sea is fundamentally important to understand, as one must be familiar with their surroundings and as Earth is 75% water, with only 25% land; it is important for everyone to understand the basic characteristics of the ocean and the sea, to separate it from one another. Both the oceans and seas are large water bodies to be precise, salt water bodies.

What Is An Ocean?

An ocean is nothing but a gigantic mass of water body present on earth. It is a large saltwater body that is boundless across the surface of the earth as dominant. It almost covers three-fourths of the surface of the earth. As per the geographical divisions of oceans, we have the following oceans:

  • Atlantic ocean
  • Indian ocean
  • Pacific ocean
  • Arctic ocean
  • Antarctic ocean

What Is A Sea?

A sea is defined as a small subset of the ocean, where it meets the land. Any mass of the body that subsects and meets the land are called the sea. It is a saltwater body that is either girdled by land on almost all sides or it is part of one of the above-mentioned oceans of the earth. This is why seas are often either fully or partially enclosed seas. For example, the Arabian Sea, Caspian Sea, Mediterranean Sea, Red Sea, Black Sea, etc.

Thus, from this, we know that a sea forms a smaller portion of the ocean and it is usually the area where the land meets the ocean. It also helps to know the classification of the animal kingdom, as one can have a full understanding of the ocean aquatic life.

Seas and oceans are different distinctively. They differ from each other in various aspects. A sea forms a part of the ocean. Sea can be found on the land regions, unlike oceans. Listed below are the differences between sea and ocean.

Difference Between Sea And Ocean
A gigantic mass of water is termed as the Ocean. A smaller portion of the ocean, where the water meets the land is termed as the Sea.
An ocean is usually huge with little to no land near it. They are usually termed infinite or boundless. A sea is usually enclosed partially or completely by land.
Light cannot penetrate deep inside the ocean beds Light passes through the water to the sea bed as they are shallow. Hence light can reach the bottom.
It is impossible to reach the ocean bed, as the waters are incredibly deep. It is possible to reach the sea bed to extract samples from the sea bed.
Oceans are away from land hence aquatic life is scarce Aquatic existence is abundant as seas exist around the land
Primary life forms seen existing are bacteria, shrimp, microscopic planktons, etc They inhabit a large portion of marine life as sunlight can penetrate deep
Oceans are much deeper than seas Land usually enclose seawaters hence they are not as deep



Q.1. Which is the smallest ocean in the world?

  • The Atlantic ocean
  • The Arctic ocean
  • The Southern Ocean
  • The Indian Ocean

A.1. The smallest ocean on the planet earth is the Arctic ocean.

Q.2. Which is the sea that is known to be the only sea without shores?

  • The Labrador Sea
  • The Celtic Sea
  • The Sargasso Sea
  • The Norwegian Sea

A.2. The only known sea without any shores is the Sargasso Sea

Q.3. What are tides? What causes tides in water bodies?

A.3. Tides are the fall and rise of the sea levels that are caused by a combination of the effects of gravitational forces that are exerted by the sun and the moon and the Earth’s rotation.

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