Salinity is the most significant feature of Ocean Water. It helps us to determine the other physical properties like temperature, density, thermal conductivity and compressibility.
In the previous post, we have discussed the Regionalization of the Oceans. So, now we will understand the physical features of the oceans.
Salinity refers to the total amount of dissolved materials measured as grams per kg, parts per thousands.
According to the International Commission, Salinity= 1.8*Chlorinity, defined as,
Quantum of dissolved material when organic matter has been oxidised; Iodine and Bromine have been converted into Chlorides and Sulphides are converted into equivalent of Chlorides. Other compounds are transformed into oxides.
Salinity influences oceanic circulations, marine life and existence of Corals. So, according to the law of constancy, Salinity across the latitudes may vary but the proportion of various salts remains constant.
The salinity of Ocean Water: Controlling factors
Insolation and Evaporation
Process of Evaporation is the most important factor. This controls the distribution of surface salinity. Actually, one should understand the fact, in the process of evaporation only pure water evaporates. So, when water evaporates, salt remains behind.
So, one can conclude, as the evaporation increases salinity increases. Evaporation is dependent on the following factors,
- Relative Humidity and
- Instability or Stability in the lower layers of the atmosphere.
Any kind of Precipitation whether it is Rain, Hailstorm, Snowfall etc, decreases Salinity of ocean water.
Actually, precipitation is the source of pure water which dilutes the seawater as well as the salinity. Because of the dilution salinity decreases.
It is effortless to understand, higher the atmospheric pressure means higher compressibility. As compressibility increases, the suspended salt dissolves easily. So, as salinity increases.
Winds affect the Salinity of Ocean Water
Winds with a greater flow have kinetic energy. So, this produces the heat due to friction and increases the evaporation rate.
So, as we know, increased evaporation increases salinity. One can conclude high-speed winds increase the salinity of seawaters.
The Influx of River Water
River water is the source of pure water. River water contains only 2% of Sodium Chloride. So, as river water meets oceanic water, it dilutes its salt content, which correspondingly decreases salinity.
Melting of Ice
Melting of ice results in mixing of saline water with the freshwater. This mixing decreases salinity.
Warm ocean currents increase the dissolving capacity if salts in the ocean. So, this increases the salinity of oceanic water.
Whereas, Cold ocean current decrease the dissolving capacity and salinity decreases, respectively.
Biotic Life affects the Salinity of Ocean Water
In temperate region Red Algae and in tropical region Saragasum increases the salinity of ocean water.
Rate of evaporation increases in landlocked countries. Because land has low specific heat, it transfers its heat to the sea. So, this increases the salinity of ocean water.
So, guys, this was all about, Salinity and Factors Affecting Salinity of ocean water. In the upcoming post, we shall read about the Salinity distribution over the world.
Thanks and Stay Blessed.