Oceans cover 70% of the earth. Oceans have always been an area of intrigue for mankind. We all are fascinated by oceans, the great expanse of water covering majority of the earth. Oceans have their own distinct properties which are difficult to understand.
One such property of oceans would be discussed today by us in the article below.
One of the main questions which people have about oceans is why are oceans salty? The answer to this question which we have been given in schools does not provide us with the entire picture.
While, in our school, our teachers have told us that this is because of the salts which are present but in the school teachers did not explain where do those salts come from and what are those salts and we would be going into the details of this question to find out the exact and the more detailed answer.
Why are oceans salty?
In order to understand this, you need to consider oceans as a collection of water which has been washed away from the earth. That is why, the salts which are present in the earth that is in the rocks as well as in the soil as well as on the land are washed away by this water and they reach the oceans.
If you look in to the composition of rock they would be containing calcium carbonate along with sodium chloride along with magnesium sulphate. All of these are a type of salt. Sodium chloride is also known as table salt whereas calcium carbonate is known as limestone and magnesium sulphate is known as epsom salt.
As you can see, the rocks over which the water flows countless number of times and in countless instances, before reaching the ocean contain a lot of different type of salts which are absorbed by the water and then it reaches the oceans.
When the water is continuously flowing over these rocks, there is wear and tear in these rocks which results in the salts being absorbed by the water. This water then flows through the streams and the rivers and the tributaries into the oceans.
In order to understand the wear and tear of the rocks, you just need to look at the marble tombstones which are present in any cremetery. When you look at the old tombstones, you would realise that the text which is written on them cannot be deciphered and cannot be understood. This is because of the continuous wear and tear which has occurred due to rain as well as wind. This is a prime example of the wear and tear due to which are part of the stone or rock is destroyed. In the same way, due to the water flowing over the rocks, there is wear and tear in the rocks which causes the salts to be absorbed by the water.
Another source of salt in the oceans is in the form of volcanoes which can be near the oceans on which can be under the oceans as well. You would be surprised to know that there is a considerable amount of volcanic activity inside the oceans as well. Since it is entirely submerged or is in places which are not easily accessible to mankind, we do not get to know about it easily. The lava which comes out from the volcano does not contain any of the salts which we mentioned above but the substances which contain these salts are thrown up into the air due to the volcanic activity. When they are thrown up into the air, they eventually come down and fall into the oceans. This again increases the content of salts in the ocean water. This is another source of salts in the oceans.
You might be thinking that, since such a large quantity of salt is continuously being added to the oceans, by now the oceans would have become extremely salty but they are not that salty yet. What is the reason for this? It is because while salt is being added to the oceans in great quantities, it is also being removed from the oceans as well.
One of the prime example of the reduction in the quantity of salts in the oceans is due to the shellfish and other similar creatures which use the calcium carbonate which is present in the water to build their shells and similarly there are many other such creatures as well which use a large quantity of calcium carbonate and because of this the quantity of salt in the oceans has remained more or less the same over a long long period of time.
It is not such that, each and every ocean is having the same quantity of salt but most of the oceans are around average but there is a sea which is having a much greater quantity of salt as compared to the other oceans and it is known dead sea which contains salt quantity up to 9 times the normal ocean. The total percentage of salt quantity relative to the water content in this sea is up to 32% of the total water volume.
If you look in to the map of dead sea you would realise that it is enclosed on all sides and therefore the salt which is getting delivered to that sea does not have any outlet and similarly due to such high salt content there aren’t any living creature is consuming the salt in dead sea as well and therefore the quantity of salt in the dead sea keeps on increasing as well. Due to this, over the years the quantity of salt in the dead sea is increasing at a gradual pace and therefore these days it is one of the most saline type of sea which is present on our planet.
So, oceans are salty because of the various types of salts which are continuously being added to the oceans due to the volcanic activity as well as due to the water which is joining the ocean via the rivers as well as streams as well as tributaries from the land which in turn bring a lot of salt infested water along with them which gets added to the oceans continuously but due to the various creatures living in the oceans, who use some of these salts, the overall quantity of salt in the oceans remains more or less the same and thereby maintaining an equilibrium.