Surprising Facts About the Salinity of Seawater

Shutterstock/Zaid Saadallah

Have you ever wondered why seawater is salty? Well, there is a scientific explanation behind it but many people never bother to question the phenomenon.

Well, this article provides a detailed analysis of the water cycle and an answer as to why seawater is salty. Read on to learn.

Interesting Fact

Did you know that only 1% of the water on earth is fresh and in a liquid state? Well, the other 2% of freshwater is in ice caps, soils, and glaciers!

Why Sea Water is Salty

What do you think is the role of the sun in the galaxy? When this crucial star is mentioned, you’re likely to think about warming and photosynthesis, right?

Well, here is your surprise;

The sun cannot be negated when explaining why seawater is salty. It plays a critical role in the water cycle!

Here is how;

When the sun heats the water on the earth’s surface, it changes into vapor through a process called evaporation. When the vapor rises into the air, it cools off to form clouds. Eventually, it falls from the sky as rain, snow, hail, or sleet.

Immediately after getting to the earth’s surface, the water flows into the rivers and finally back into the sea and the cycle continues.

Where Does the Salt Come in?

You’re probably wondering how the water cycle is related to salty seawater, right? Well, the truth is that rainwater is not neutral; it mixes with sulfur dioxide, carbon dioxide, and other acidic gases in the air.

When the rain falls into the ground, the acidic water further reacts with mineral salts from rocks on the earth’s surface. The mineral salts include sodium and chloride which explains why sodium chloride is the most common salt in the seawater.

As such, the water will flow into the sea with numerous dissolved salts.

Salt Accumulation in Sea Water

While the salts that get to the sea are actually in low quantities, they accumulate to raise the salt level significantly. The current levels of salt in seas have been achieved after an accumulation of over 30 billion years!

Additionally, as the seawater evaporates, salts are left behind which further increases their concentration. The more evaporation occurs, the saltier the water will be.

Finally, seawater may acquire more salts from hot vents located on the ocean floor and other volcanic surfaces.

Why Are Streams Not Saline?

Are you wondering why streams have freshwater yet they deliver salty water into the seas? Well, rivers and streams only contain low levels of salt. The only reason that seawater is more saline is due to accumulation over many years.

Amusing Fact;

Seawater contains more than 300 times dissolved salts that river water! Every one liter of the water contains approximately 35 grams of salt.

Why the Sea Water Is Not Getting Saltier

Despite water flowing continuously to the sea, the concentration of seawater remains relatively the same. But why is this so?

Well, the algae and animals living in the sea remove some of the salts. Also, a proportion of the salt sediments on the base of the sea

Is the Amount of Sea Salt Universal for All Seas?

The salinity of the seawater differs from region to region depending on temperature levels. In warmer areas, there is more evaporation which leads to saltier seawater. On the contrary, seawater in colder areas is significantly less salty.