Why is seawater salty while that of rivers and lakes is sweet?

Even if you have never taken a broth in the beach or choked on a golon while playing with friends in a river, you may have heard a thousand times that seawater is salty, while that of rivers and lakes It's sweet, isn't it? But can you tell why this difference exists? The salinity of the seas is actually the result of several natural processes, including the arrival of river water in the ocean.

Freshwater comes from the rain that falls on the planet's surface, supplying the rivers, lakes and aquifers that serve to “quench the thirst” of humans, animals and plants. This cycle occurs continuously, and each time water evaporates and goes into the atmosphere in the form of vapor, when it precipitates and falls back on Earth, rain essentially does not contain many salts in its composition.

Rain rain

But in addition to supplying these water bodies mentioned above, rain also falls on rocks and sediment and as this water travels the surface of the planet, it collects minerals, nutrients and other elements.

In the case of water from rivers and lakes, rain replenishes these water bodies constantly, not allowing them to become salty, although they are not completely devoid of minerals and salts either. On the other hand, seawater collects all the minerals and salts carried by the rivers that flow into the ocean.

Once Upon a time...

In the early days of the earth, when the seas were still young, their waters were only slightly salty. However, over time, that is, over 4.5 billion years, as the rain fell on the planet and over its surface - causing the erosion of rocks - this whole water ended up carrying a lot of salts. and minerals into the ocean, making it progressively saltier.

Moreover, just as evaporation of rivers and lakes occurs, this process also occurs with the sea, causing an increase in its concentration of salts and minerals. Not to mention volcanoes and other structures that exist at the bottom of the ocean that contribute by releasing more salts and minerals into the waters. In fact, within a few billion years, with all these processes going on, you can be sure that the composition of the ocean will be quite different from today!