Why sea water is salty and river water is sweet

We all know that around 97% of water present on the earth surface is saline and oceans and seas are major contributors to the count.

Well this is a question every one of us might have wondered sometimes in their life. Why do sea water or ocean water are salty to taste when the rivers or little streams of water which acts as a carrier are somewhat sweet to taste.

Before we get down to that, do you know it is said that if we remove all the salt from the oceans and seas and bring it onto the land surface you would have a huge layers of salt at around height of ~150 metres. 

Coming back to our question of why.. We all have studied Water Cycle in our school times. Below image for reference.

So we are aware that the rain water which comes in contact with atmosphere becomes a little acidic in nature. On top of that when it travels through the mountains via little stream of water and the rivers and then to the seas, it carries the salts or particles when there is a slight erosion from its contact with rocks.

Now these particles are carried out to the seas and oceans. As the amount of salt increases the salinity of the water body be it sea or ocean keeps on increasing thereby eventually increasing the salt content in it.

You can take an example of a fresh water in a glass, keep adding salt after regular interval of time. Eventually the water will be too salty even to drink from it.

Now you might think, Oh so rivers are the carriers of those particles.. Then why aren't they salty to taste??

So looking at the water cycle diagram, From evaporation to condensation to precipitation, we can see that rain water typically replenishes the river water from time to time. Its like going by our glass of water example, it kind of empties half the glass and refreshes it with more fresh water.

Why does the same does not happen with sea and oceans?? So its kind of related to how much of salt comes in and how much goes out. Once the salt or minerals reaches the sea or ocean, the salt stays and water gets evaporated as part of water cycle. Even if we consider some salt gets carried out by still the difference is negligible.

 Also there are climate shift to consider like the case of  huge salt deposits in Mediterranean sea which was once dried and then later got filled through the Atlantic stream.

So there may be a chance that the oceans or seas might be fresh or have a little bit of salinity in them. However as time progressed and the water cycle did it's part the salinity increased eventually.

Well, that's about the topic today. Until the next one comes, remember the curious mind talks! :)

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