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Sometimes we use the words ocean and sea interchangeably to refer to large bodies of salt water. For this reason, many people think that they are the same, but in reality there are differences between the two concepts. The main difference between oceans and seas is their extension, but it is by no means the only one, since there are many more. In this Green Ecologist article, we tell you what is the difference between sea and ocean so that you will never confuse them again and can distinguish them.
What is a sea
The concept of the sea is neither more nor less than a large expanse of salty water that may or may not be connected to an oceanalthough usually it is. It is common for people to ask themselves, which is bigger, the ocean or the sea?
In general, the seas are smaller than the oceans and are shallower than the oceans. The seas do not usually have natural outlets and are close to the Earth. They usually connect the land to the oceans. In addition, waves are formed in its waters. The main seas of the world are:
- Mediterranean Sea: it is the largest sea in the continental interior of the planet, with an approximate extension of 2,500,000 km2 and it is located between Europe, Africa and Asia. It connects with the Atlantic Ocean through the Strait of Gibraltar.
- Baltic Sea: it is one of the seas of northeast Europe and has an area of 377,000 km². It is an inland sea with brackish water, that is, it has more dissolved salts than fresh water, but still has less than sea water. If you want to know why sea water is salty, take a look at this other Green Ecologist article.
- Aral Sea: it is located in Central Asia and has an area of 6,800 km2. It was known as one of the largest lakes in the world, until it was considered a sea. At present its surface has been reduced by more than 10%, which is considered one of the biggest environmental catastrophes of the plant.
- Dead Sea: has an area of 605 km2 and is located in the Middle East. Due to climate change, the waters of the Dead Sea are reduced by 1 meter every year and the riparian lands fall 15 cm. Find out why it's called the Dead Sea, here.
- West Indies SeaAlso known as the Caribbean Sea, it is located between Central America and South America and has an area of 2,763,800 km². The first known exploration of this sea was by Christopher Columbus in 1492.
- Caspian Sea: located in southeastern Europe, it has an area of 371,900 km2 and there is debate as to whether it is the smallest sea that exists, or the largest lake. If you want to discover the answer, visit Why is it called the Caspian Sea if it is a lake.
- Red Sea: it has an area of 450 thousand km2 and it is located between Africa and Asia. It acts as an important communication channel between Europe and the Far East.
- Black Sea: It is located between Eastern Europe and Western Asia. It has an area of 436,400 km2 and a maximum depth of 2,212 meters. If you are curious, you can find out why it is called the Black Sea.
What is an ocean
The oceans represent large expanses of salt water that are part of the hydrosphere of the planet. Oceans cover most of the earth's surface and even separate continents. Historically, there have always been four oceans, until in 2000 the International Hydrographic Organization added the Southern or Antarctic Ocean to this list. In this way, there are currently five oceans in the world:
- Atlantic Ocean: this ocean separates the continents of America, Europe and Africa. It has a length of 14,700 meters, from north to south, and a maximum width of 11,800 kilometers, from the Gulf of Mexico to the Black Sea. It reaches a maximum depth of 8,605 meters in the Puerto Rico trench. Covers approximately the 20% of the earth's surface, since it extends over an area of 81,760,000 km2. It is the most important ocean of the five from the point of view of trade flows, whether export or import. If you want to know more about this ocean, do not hesitate to read the Atlantic Ocean: characteristics, flora and fauna.
- Pacific Ocean: it occupies 166,241,000 km2, so it is about the ocean with greater extension of the five that exist. It has a maximum depth of 10,924 meters in the Mariana Trench and is located between the continents of Asia, America, Oceania and Antarctica. It should be noted that it communicates with the Atlantic Ocean through 3 connections: the Strait of Magellan, the Panama Canal and the Drake Sea. If you are curious, do not hesitate to read Why the Atlantic and Pacific Oceans do not mix in this other article.
- Indian Ocean: occupies almost 74 million km2 and it bathes the coasts of East Africa, the Middle East, South Asia and Australia. It has a maximum width of 10,000 km and its surface occupies 68,556,000 km². It became known as the Indian Ocean from the year 1515, since before it was called Eastern Ocean. The first civilizations formed around the Indian Ocean.
- Arctic Ocean: occupies 14,056,000 km2 in the Northern Hemisphere, making it the smaller ocean of all the Earth. Its maximum depth is 5,607 meters in the Molloy Chasm. It is largely covered by ice masses that protect it from atmospheric changes. Its temperatures in winter can reach -50 ºC and, in summer, it does not exceed 0 ºC. If you want to learn more, do not hesitate to read the Consequences of the thaw at the poles.
- Antartic Ocean: also known as the Southern Ocean, it occupies 20,327,000 km2 of surface and is in the South hemisphere. Its maximum depth is 7,235 meters in the South Sandwich Trench.
Differences between seas and oceans
Although at first glance they may seem the same, there are some differences between seas and oceans. Next, we are going to detail them.
Extension
The main difference between the two is their extension, since the seas are smaller than oceans. In addition, the seas are closed, located between the land and the oceans, while the oceans are open, deeper and with strong ocean currents. Also, there are seas that, due to their size, are considered large saltwater lakes. In this group, the Caspian Sea, the Dead Sea and the Aral Sea can be included.
Depth
Due to its greater depth, oceans reach lower temperatures than seas, approximately 4 degrees at any point. On the other hand, because the seas are closer to the land masses, they receive greater solar radiation and reach higher temperatures than the oceans, although this varies between the different seas. Thus, for example, the waters of the Mediterranean Sea are warm and those of the Dead Sea are cold. Precisely, due to their proximity to the land, the seas suffer greater desertification with increasing global warming, while the oceans have increased their volume of water due to the melting of the poles and glaciers.
Biodiversity
As for life, seas have greater biodiversity in number of species than the oceans, due to the greater solar radiation they receive, while the oceans are home to fewer species, but more adapted to the depths and low temperatures. The seas, on the other hand, are more exposed to environmental pollution than the oceans and, as a consequence, to higher species mortality.
Keep learning by reading this post by Green Ecologist to know how to avoid pollution of the seas and oceans.
If you want to read more articles similar to Difference between sea and ocean, we recommend that you enter our Ecosystems category.
