Why is the ocean water salty?

Why the ocean water isc salty?

The reason why ocean water is salty is because they contain very large amounts of salt. On average, the oceans on Earth contain about 3.5% salt (sodium chloride), which is the equivalent of a total of about 50 million billion tons of salt. If you spray all of this salt on the land, they are enough to create a layer about 152 meters thick.

How did this huge amount of salt reach the oceans? According to the study, part of the salt is derived from rocks and seabed sediments. Other salts escape from volcanic vents hidden deep in the waves. However, most of the salt in the oceans comes from the land that surrounds us.

Rainwater dissolves minerals and salts from rocks and dry soil, then swept them away into the river. However, the salt accumulation in rivers is still very small, less than 1/200 of the amount of sodium chloride exists in seawater. So much of this salt still accumulates there and eventually reaches the oceans as river water flows through the estuaries.

Importantly, the salt is then more concentrated in the oceans, due to the sun's heat causing the surface water to evaporate, leaving the salt behind. Globally, 4 billion tons of salt from rivers enter the ocean each year. Therefore, our oceans are bound to become much more salty and salty than in the beginning. However, the amount of salt added each year from the rivers is now generally in balance with the salt accumulating back to the bottom of the sea.

The salinity of the sea water is not the same across the Earth. In the polar regions, seawater is not as salty as elsewhere because it has been thawed and dissolved. Meanwhile, in tropical areas around the equator, the increase in the amount of hot heat causes water to evaporate more than rainwater to fall, making the sea saltier.

There is growing evidence that salinity differences across the globe are increasing. For example, as sea temperatures rise, a portion of the Atlantic accelerates evaporation and thus increases the salinity of the seawater. This may seem insignificant, but the more salt in the oceans, the more salty the seawater will be and the slower it will flow, affecting the flow of essential nutrients in the ocean. .
Tuấn Anh (according to BBC)