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23 Types of Seas – Classifications and Benefits

by Zidni

The Earth as the only planet in the solar system that can be inhabited by humans has a surface appearance that consists mostly of water. Although humans and most animals and plants live on land, the surface area of ​​the Earth in the form of water is even wider than the land area. The waters on the surface of the Earth have many types, including the sea, oceans, various lakes, rivers (read: the benefits of rivers), swamps, and so on. All of this gives an appearance in the form of water and can be used in everyday human life.

One of the features of the waters on the surface of the Earth is the sea. Yes, we have heard about the sea often, see lots of it, research, or even work on it. This sea is vast water, has salty water and has tidal benefits in the water. The sea usually has a watercolor that looks blue. On the map, we can see this sea that is depicted in light blue. The vast sea is called the ocean. This article will specifically discuss the sea, especially regarding the types of the sea.

Definition of the sea

Before entering into a deep discussion on various types of sea, it is better if we know how to define sea. Definition of the sea is a collection of salt water which is very large or extensive in number and is directly related to the ocean (read: list of oceans in the world). Apart from being related to the oceans, the sea is also associated with rivers, where a sea is a place where the rivers on the surface of the Earth emerge. The meeting place of the river with the sea is called the river estuary. In this river estuary, there is usually a meeting of salt water with fresh water, this is because the river has a taste of fresh water while the sea has salty water.

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The sea is vast salty waters. The sea does not only have one type. The sea turned out to consist of several types. These various types of sea can be seen according to several characteristics. In general, the sea is grouped according to five classifications, according to its location, according to its depth, according to its extent, according to the process of occurrence, and according to its relief. Of all kinds of marine classifications will be explained as follows regarding the types of sea

According to the location

Based on the location of the sea itself, the sea is divided into five types. The five types of sea are as follows:

1.Sea edge

The first type of sea according to its location is the sea edge. Sea edge is an ocean that is on the edge of the continent. Because the sea is on the edge of the continent, the sea is called the sea edge.

2. Mediterranean

The next type is the Mediterranean sea. The Mediterranean Sea is a sea that lies between two continents. This Mediterranean Sea is flanked by two continents, hence it is called the Mediterranean sea.

3. Inland sea

The third type of sea-based on its location is inland sea. Named inland sea because it is in the middle of the continent. So from that, the sea is called the inland sea.

4. Strait

The type of sea that is based on the location of the sea is the strait. The strait is a narrow sea located between two islands or continents. In Indonesia, which is an archipelago, there are many straits in Indonesia. for example, the strait in Indonesia is the Bali Strait (between Java and Bali), the Sunda Strait (between Java and Sumatra Island), the Madura Strait (between Java and Madura Island), and much more.

5. Bay

The last type of sea-based on the location of the sea is the bay. The bay is an ocean that lies jutting inland. The bay is shaped like a basin but is horizontal and concave towards the mainland. We also find the Gulf in Indonesia. Some examples of bays in Indonesia are Teluk Bayur.

That’s the kind of sea-based on its location. Furthermore, the types of the sea will be explained based on their depth.

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According to the depth

According to the depth of the sea can be divided into four types. Actually, the sea according to its depth is the parts or areas of the ocean according to which are measured according to their respective depths. The four types of sea-based on its depth will be explained as follows:

1.Littoral Zone

The first type of sea-based on the level of depth is the littoral zone. The littoral zone is the part of the sea located on the coast, which lies between the tidal sea and the tidal sea.

2. Neritic Zone

Besides the littoral zone, there are also neritic zones. Neritic zone is the shallow part of the sea which is only about 200 meters deep.

3. Bathyal Zone

In addition to the littoral zone and neritic zone, there will be a bathyal zone. The bathyal zone is an area in the deep sea with depths ranging from 200 to 2000 meters.

4. Abyssal Zone

In addition to the three zones previously explained, then there is a special zone. Of all the zones described, the abyssal zone is the deepest zone. This abyssal zone is found in a very deep sea that has a depth of more than 2,000 meters.

That is some kind of sea or parts of the sea that are divided according to the depth of the sea itself. Furthermore, the types of sea will be explained based on the area of ​​the sea.

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Based on the area

When viewed from the size or area, the sea is divided into four types. The four types of sea are among others:

1.The ocean

As previously explained, the ocean is a collection of several seas, it can also be said that this ocean is a sea which is very large in size. Besides having a large size, these oceans usually also have very deep depths. There are many oceans that we will meet on this Earth. some oceans located near Indonesia are the Pacific Ocean and the Indian Ocean.

2. The sea

Under the ocean, there is one level of the sea that extends below the ocean. These waters are also called the Sea. As we all know that the sea is a very large collection of saltwater and is directly related to the ocean. The sea has an area that is not as warm as the ocean. Even some of the seas will gather together to form an ocean. We can find several seas in Indonesia. Some of the seas that we can meet in Indonesia include the Java Sea, the Sumatra Sea, the Arafura Sea, and so on.

3. Strait

After the ocean and also the sea, then the strait. As explained earlier, the strait is a narrow sea (not too wide) that is flanked by two islands or continents in the world. In fact, from the two islands which are only separated by straits, we can see one island from one island opposite it. To cross the strait also does not require a long time, only about 30 minutes to one hour by ferry. Indonesia has a lot of straits. Some straits in Indonesia are the Bali Strait (between Java Island and Bali Island), Sunda Strait (between Java Island and Sumatra Island), Madura Strait (between Java Island and Madura Island), and so forth.

4. Bay

Besides the three above, one more type of sea according to its area, namely the bay. The bay is a sea jutting inland. So this shows that this bay is like a horizontal basin. When viewed from its breadth, this bay has an area that is not too wide because some of its edges directly border the land. We can easily find this bay in Indonesia. In Indonesia, there are several bays that we can meet, for example, Teluk Bayur.

Those are some types of sea, seen from the size or breadth of the sea. Next, is the variety of the sea when viewed from the reliefs.

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Based on the Relief

Relief is a form of the sea itself. Based on the relief, the sea is divided into seven types. Actually, this sea relief is more directed at parts than the sea itself. There is a sea that has these parts in full, but there are also seas that do not have all parts of the sea relief itself in full. The seven types of sea reliefs will be explained as follows:

1.Shelf exposure

The first sea relief is continental or shelf exposure. This continent’s exposure is the basis of a shallow sea that has an average depth of only 200 meters. Apart from having a fairly shallow depth, continental or shelf exposures are located along the coast of a continent or around or the periphery of the continent. We can easily see the contents of this continent everywhere. Some exposure to the continent in Indonesia that we can meet for example is the Sunda Exposure and Sahul Exposure.


After exposure to the continent or shelf, the part or relief from the next sea is the sea trough. A sea trough or trench is a very deep and very narrow sea floor that has steep walls and forms like a funnel. It can be said that sea trough is part of the deepest sea. This sea trough is said to be like a cliff in the sea. The depth of this sea trough reaches 5,000 meters or more. This trough looks like a very horrible place in the sea. On this Earth, we can find several troughs in the ocean. Examples of troughs that exist in the oceans that are on Earth are the Mindanao Trench which has a depth of 11,500 meters.

3.Deep sea (bekken)

After exposure to continents or shelves and also sea troughs or trenches, one of the reliefs from the next sea is the bottom of the sea or bekken. Deep sea or bekken is part of the sea floor in the form of a basin. So that it can be said that the depth of the sea is like a well in the sea. Even though the sea floor is concave, but the depth of the sea has a depth not as deep as a sea trough. In other words, the bottom of the sea is more shallow than sea trough. In addition, the ocean floor also has no steep walls and is not shaped like a funnel like a sea trough.

4.Sea mountain

Then there is the sea mountain. Mountain sea is one type of relief from the sea. As the name implies, sea mountain is a mountain that is basically found in the sea. This sea mountain has a peak that rises to the surface of the sea and inside the sea surface. Both those on the surface and inside the sea, if the base of the mountain is inside the sea area, then the mountain is said to be a sea mountain. In Indonesia, there is a sea mountain that is very well known by the community, namely Mount Krakatau and Anak Krakatau.

5.Back of the sea

The next sea relief is the sea back. This sea back is a sea relief in the form of mountain ridges on the sea floor. The sea back is long because it is the back of the mountains.


One type of relief in the sea is atoll. Atolls are coral islands found in the sea which have a very large ring-like shape. It can be said that this atoll has a circular pattern because it has a ring-like shape. Coral islands in the sea are usually used as houses by ornamental fish, as well as other marine plants and plants.


The last sea relief to be explained is a lagoon or lagoon. This lagoon is one part of the shallow sea in the middle of the atoll. Or it could also be said that lagoon is part of a shallow sea which is blocked by sand or rocks. This lagoon is usually used as a playground when we visit the sea and want to play with the sea. Laguna is a place that is very suitable for swimming because of its shallow or not deep nature. In addition, because the lagoon is surrounded by sand or coral, there are no big waves that will attack the lagoon, so it is safer to swim there.

That is some relief from the sea that is commonly encountered. The reliefs indicate the condition of the sea is different. Next will be explained the types of sea according to the process of occurrence.

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According to the Occurrence Process

Next, we will discuss together the types of sea according to the process of occurrence. The sea according to this process is divided into three types. The three types of sea among others are:

1.Sea Ingression

The first type of sea because of the process of occurrence is sea ingression. This ingression sea is a sea formed due to a decrease in the sea floor with a depth reaching more than 200 meters.

2.Sea Transgression

The second type of sea-based on the process of occurrence is sea transgression. Sea transgression is the sea that occurs because of the elevation of sea level which has a depth of fewer than 200 meters.

3.Sea Regression

The third type of sea-based on the process of occurrence is sea regression. Sea regression is a sea formed due to the sedimentation process of land mud entering the sea due to land erosion.

That is some type of sea when viewed from the process of its formation. And that is also the type of sea according to its various characteristics

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Benefits of the Sea

As one part of the earth’s surface in the form of vast waters, the sea certainly has many functions or benefits, such as river benefits and lake benefits. The functions or benefits of this sea can be easily felt both in daily life and periodically. Some of the functions possessed by the ocean include the following:

  1. Recreation and entertainment place. A sea is a place of recreation and vacation spot that is fun for anyone, especially for family or friends. Because the sea has a large area, the sea is very suitable to be a holiday place together with loved ones.
  2. Power plants. Not only a waterfall (read: the highest waterfall in the world) or a river that has a heavy flow that can be used as a power plant, but the sea can also be used as a power plant. The sea can be used as a power plant because of waves, winds, and tides. The elements in the sea can be used as a power plant.
  3. As a mine item. Sea is also used as a place of mining goods located. Many mining goods that we can find in the sea, such as petroleum and other liquid mining goods.
  4. Living places for various food sources. As we all know that we as humans have a source of life in the form of vegetable and animal origin. One of the sources of life or animal food that we need is in the ocean. Sea is the environment for various kinds of food, such as fish, shrimp, squid, and other types of seafood.
  5. As a water transportation route. The sea is also one of the transportation routes that connects two islands or two continents or even more. The sea which is one of these transportation routes can be passed by using water vehicles such as boats, boats, and so on. As a transportation route, the sea is one of the pathways that rarely experience congestion such as land routes.
  6. One place to store water reserves. The sea is one of the large reservoirs of water reserves. When this earth experiences drought and requires a lot of water supply, the sea is ready to be a place that can present this solution. Water in the oceans can be used for various purposes or human needs as well as other living things in need.
  7. As one source of drinking water or desalination. The sea is a place to store lots of water. Therefore, this sea can be used as a source of drinking water. Although the water in this ocean has a salty taste (read: various types of water on Earth) and is not suitable for use as drinking water, with special processing or certain processing, the salty sea water can be used as a source of drinking water.
  8. As an object of research or development of education. This is one of the educational functions owned by the sea. The sea which is one of the natural resources can be used as an object of research or research development, and also education. There are many research programs that can be done in this sea. In addition, anyone can do a research program at sea, whether it is researching the content of seawater or the organisms that live in the sea. But keep in mind that research carried out at sea must be done by obtaining prior permission from the authorities.
  9. As a template for hazardous waste or waste disposal. A sea is a place that can function as a hazardous waste disposal site. However, this function is a bad function if done for a long time because it can pollute the seawater itself.

Those are some of the benefits that we will get from sea water. We will feel these benefits both directly and indirectly.

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