Home » Environment » Salinity of Ocean Water – Meaning – Factors – Temperature

Salinity of Ocean Water – Meaning – Factors – Temperature

by Sekar Puspa

The ocean is the biggest natural resources in the world. It provides many kinds of goodness to the human life. On the other hand, there is a term which is associated with the event of ocean water. Yes, it is salinity. Hence, what actually the salinity is?

Well, salinity is a thing which is being controlled by the balance level between the evaporation of water removed and the freshwater added by rain and also the rivers. Besides, the theories for explaining the origins of the ocean salt in which the salt and minerals were brought into the ocean by the rivers. Both of them would be concentrated as the evaporation process to remove the water. Furthermore,  it is that seawater has limited PH which is range from 7.5 to 8.4.

We may think and have known that seawater is salty. However, we may do not know about the process, the effect, or how the salinity exists in ocean water. Indeed, the salinity can affect the water cycle and ocean circulation. As the consequence, it is known that the rocks deliver minerals such as salt into the ocean.

Also, the evaporation of ocean water will increase the salinity level of the ocean. This raising salinity event is really caused by natural events. Yet, there is also a term which refers to the decreasing level of salinity. This one occurs in the ocean water due to the presence of fresh water from the rivers, the melting ice events and the precipitation of rain and also snow.

See also :


The salinity level in the ocean is different from one ocean zone to other ones. Take one as the example, Lake Vanda is being categorized as the Salt lake as it has 35% percentage of the salinity water level. On the another hand, the Dead sea has 33.7% salinity in percentage while ocean water in the world also has approximately 3.5% of salinity level on average.

Besides, the 3.5% of salinity level refers to 35 parts per thousand term. It means that every 1000 mL of ocean water contains 35 grams of salts. Then, what kinds of salts contained in the ocean water? Well, it shows that mostly sodium chloride takes the bigger percentage of the level.

Red Sea

If you are curious about what is the most saline ocean in the world, then now you will discover that the Red Sea is the one. This event caused by the high temperatures and the result of captive circulation which evaporates the surface. What is great from the higher salinity level is the presence of high amount of ions dissolved compared to the fresh water only.

As a matter of fact, the Atlantic Ocean water is a way saltier than the Pacific water. The evaporation process of freshwater from North Atlantic subtropics excess rainfall in Pacific Ocean’s western tropical regions. As a result, Atlantic gets saltier while Pacific gets fresher.

Then, it is caused by the water vapor removal process from the South Atlantic subtropics to Antarctic Circumpolar Current through the southwest-directed wind. Consequently, there is a term where salinity and temperature are being measured.

The measurement of salinity and temperature is important due to the water density and the formation of ocean currents. In another hand, we know that many chemicals in ocean water so that they result in the salty water. The salty sources come from many places such as the rivers carrying chemicals dissolved out of soil and rock.

As a result, measuring the salinity level is needed to know how much the salinity affects to the ocean. Moreover, to record the salinity, we use the amount of salt in 1000g of water which refers to ‘parts per thousand’ or commonly called as ppt. In fact, the salinity level of the ocean is approximately in range 34ppt and 36ppt as well.

See also :


There are several factors which causes salinity of water, as follows:

1. Evaporation

There are some factors which contribute to making the higher or lower salinity level. At this point, there are parts of the ocean which got hardly rain falls yet but warm dry winds which cause the higher evaporation event. Then, the evaporation removes the water and there will be salt as the result of water vapor rises into the atmosphere. These processes explain the process of increasing level of salinity.

Take one of the examples, Mediterranean sea in Europe is the one which has the very high level of salinity by having 38ppt or even more. For this reason, it explains that there is a higher evaporation level than there is rain or the addition of fresh water from the rivers.

2. Water Cycle

As water takes the long journey from the river to the sea, then this water cycle contribute a lot in making the salinity of ocean water. We know that every process in the river or through by the falling rain, they might contain the salt and minerals in it. For this reason, water cycle has a role for the salinity level in the ocean.

Water cycles take part in making the increasing level of salinity. As the consequence, water dissolves rocks and sediments which create complex mineral salts in the ocean basins. As the water cycle has a role in the process of salinity, then we can see the changes of water cycle such as the melting and freezing ice sea and also the evaporation in the ocean.

3. Climate

Everyone talk about the climate, especially for the climate change. They talk about how frequently does the rain fall or the dry weather in such a long day.

Indeed, we suffer from bad climate changes now. As a result, it gives the bad impact to the human and animals living for sure. On the another hand, climate also plays the main role for the salinity of ocean water.

At this point, the climate is associated with the presence of salinity of ocean water. As a result, the winds drive currents in the upper ocean. Also, the heat which comes from the increasing of global temperature level is being absorbed and moved by the ocean.

Moreover, as studies have shown, the seawater becomes fresher while it is dominated by rain and high evaporation so that the ocean water becomes saltier.

See also : Climate of the Ocean – Effect Of Sea Level Rise

4. Submarine Volcanic

Next, the factor which contributes how the salts are in the oceans is the submarine volcanic. Consequently, submarine volcanic is the eruption of volcanoes under water. As a result, the process involves the reacting event with the rock and dissolving the mineral constituents as well.

5. Water and Temperature

In fact, water and air temperature affect the ocean’s salinity. It is due to the presence of water volume that flows into the ocean. Not only for that, the temperature and density have the relationship also. If the temperature is being increased then the space between water molecules will be also increased.

The next process involves the temperature. As the water reaches the maximum density, then it becomes less dense than the water. Thus, not only the relationship between temperature and density. However, there is also the relationship between salinity and density as well. As the consequence, while the density increases, then salinity will also be increased.

To conclude, there are three major factors involved in salinity process. There are precipitation, evaporation, and winds. As the precipitation brings the freshwater into the ocean, then it dilutes the salt concentration.

Indeed, it removes the water molecules and resulting in the presence of the salt. Also, if the regions have the higher evaporation, then it is due to the presence of winds and high temperatures as well. After that, the salinity also becomes higher for sure.

See also :

Process of Salinity

As we have talked about the places which have high salinity, then let’s take the turn to the places which have the lower salinity. Moreover, the way nature reduces the ocean salinity is by increasing the rain frequencies in a day and then the addition of the freshwater at the surface dilutes the ocean water. As a result, the ocean water becomes less dense. Not only for that, the ocean water becomes less dense and has the lower salinity may cause by the presence of rivers which add the freshwater as well.

For the example, you can find the ocean around Antarctica which has lower salinity or below 24ppt. Also, Arctic is the one which has low salinity as it has 30 ppt in places. This event is linked to the presence of freezing ocean water which could reduce the salt level. On the other hand, Baltic Sea also has a very low salinity by having 10 ppt. At this point, it is due to the high amount of freshwater added from the rivers.

As a matter of fact, the first process of salinity is the precipitation to the land, to the rivers, and to the sea. As the consequence, the rain contains dissolved carbon dioxide which causes the rainwater to be slightly acidic. Indeed, it is due to the presence of carbonize acid. As a result, the rain will erode the rock and then the acids break down the rocks as well. By doing that, the process continues the work by carrying the salts and minerals as ions.

Moreover, the ions go into the rivers and then to the ocean for sure. At this point, the dissolved ions are removed from the water. In the same way, seawater contains ions such as chloride and sodium which is 90% of the dissolved ions in seawater.

[box title=”” align=”centerThe Process

Precipitation to landdissolved carbon dioxcideimpacts to rainwaterrain erode the rockacids break along with rocksalt and mineral carried out as ions.[/box]

You may think that difference level of salinity level does not affect too much. However, the difference itself makes the change in density and the denser ocean water. As the consequence, the salinity of ocean water can affect to the natural creatures living. Then, as we have listed the effects of salinity in ocean water, it is recommended to continue reading the following statements below.

See also :


As well as causes, there are also effects of salinity, such as:

a. Changes of Ocean Water

Talking about changes of ocean water may result in a wide topic. Indeed, since a few decades ago, ocean suffer from many changes which caused by both of natural events and human activities. As one of the examples, people do deforestation to get the new land, they also do illegal logging for getting the wood for their home appliances.

Not only for that, they take tons of fish annually for fulfilling the needs of food consumption. Then, as sea face many kinds of change recently, then it also affects to the salinity of ocean water.

As a matter of fact, the salinity has a role in ocean living. For instance, the chemical substances contained in it may cause the changes in ocean water. As a result, salt makes the ocean water more dense than freshwater. Not only for that, to prevent the freezing process, salty water needs to be colder than freshwater as well.

b. Floating Ice

Floating ice means a good thing. While the world concerns about the melting ice due to the presence of climate changes, then the salinity offers the good things as it makes the floating ice as well. Indeed, the next effect caused by the salinity of ocean water is the presence of floating ice.

In fact, the combination of temperature and salinity can make changes to the water density. There will be an open structure and hydrogen-bonded molecules form when water freezes at 0-Celsius degrees. This event also causes the ice less dense than the liquid water so that it results in the icebergs float.

As the consequence, by increasing the level of floating ice, then it is valuable to save the animals living in the south and north pole zone. Also, by having floating ice, then it also means that it helps to deal with the effect of climate change for sure.

See also :

Slow Currents

The effect of salinity is not just that. There are plenty of them which makes the change in living. As the consequence, as the salty waters get cold or by having the low temperature, then it will result in the denser ocean water. This could be a serious problem as it will sinks to the bottom of the ocean and flows across ocean basins resulting in slow currents.

See also : Effects of Ocean Currents

The Importance of Salinity

The use of salinity of ocean water also comes up with several ways. For instance,  it shows that salinity can be determining the density of seawater. Indeed, the major cause of changes in density is the salinity and the temperature. Not only for that, salinity also affects the freezing point of seawater so that it makes the floating ice as well.

Salinity also delivers the thermonuclear circulation. At this point, you may feel unfamiliar with the term thermohaline circulation. However, it refers to the global density which brings the circulation of the ocean. The name of it has the meaning as heat while the saline means density. Indeed, both of the are major factors of the density level of ocean water.

Last, salinity shows the positive result in affecting a water mass including the precipitation or evaporation and the freezing event. Furthermore, the use of salinity is to determine the origin and mixing of water types.

Salinity Measurement

The awareness of changes in salinity can help to deal with things. At this point, it is a must to find out the right measurement of salinity. Moreover, the technique for measuring ocean water properties has to be the great method and accuracy development for sure. As we measure the ocean properties, then we will know the changes in ocean circulation, the cycle of freshwater, and also how to deal with global climate change which affects in rainfall patterns.

To sum up, the occurrence of salinity depends on some factors including the water cycle, winds, and also the evaporation. Indeed, evaporation increases the salinity and density while freshwater could reduce the salinity and density as well. Therefore, as one of ocean events, salinity has an important role in supporting the natural living. For the example, the salinity of ocean water surprisingly can help to melt the polar ice and increasing the form of freezing polar ice.

See also :

You may also like