Before the first trip round the whole world, the ocean was called “ocean sea”, but it is when Magellan was sailing the world ocean that he decided to call the ocean “Pacific” when he realised that the ocean he was sailing on was calm. From then, all parts of the world ocean were given a name: Atlantic Ocean, Indian Ocean, Austral Ocean, Arctic Ocean. If we look into the definitions of “ocean” and “sea” we notice that the difference between the two is very subtle. However, there are a few points that help us distinguish a sea from an ocean.
We often hear that size does not matter but in the maritime field it does. Indeed, it is a matter of size! It is the huge surface area of the ocean that easily distinguishes it from the sea. Even if the sea is also defined as a large body of salt water, its surface area is smaller. To give you a reference, the biggest sea (Arabian Sea) has a surface of 3.6 million km² whereas the smallest ocean (Artic Ocean) has a surface of more than 14 million km².
The difference between the sea and the ocean does not stop here, it is also a matter of borders! If we look into the definition of the ocean, it is written that an ocean is always surrounded by continents.
The borders and size of the water body are not the only distinctions between ocean and sea. Indeed, the salinity of water is also a factor to take into account.
Surely, it is not by comparing the taste of water that you can distinguish the ocean from the sea, even if the water in the oceans is less salty than in the seas (the salinity of oceans is on average of 35g/L). Why are seas saltier? Ocean currents enable to regulate the salinity of oceans thanks to thermohaline circulation. To understand this phenomenon better, we invite you to read our article about ocean currents.
On the other hand, seas are saltier because of more important water evaporation. As salt does not evaporate, thus sea water has a higher density of sodium chloride.
Credit : Ocean Clock
Picture Credit : Google
