It is the content of dissolved salt in a body of water. In other words, the expression salinity is valid to refer to the saline content in soils or in water. The salty taste of the water is due to the fact that it contains sodium chloride. The average percentage that exists in the oceans is 10.9% (35 grams for each liter of water). Furthermore, this salinity varies according to the intensity of evaporation or the fresh water supply from rivers increases in relation to the amount of water. The action and effect of varying salinity is called salting.
Salinity was defined in 1902 as the total amount in grams of dissolved substances contained in one kilogram of seawater, if all carbonates become oxides, all bromides and iodides into chlorides, and all organic substances have been rusty.
Salinity is an environmental factor of great importance, and it largely determines the types of organisms that can live in a body of water. Plants adapted to saline conditions are called halophytes. Some organisms (mostly bacteria) that can live in very saline conditions are classified as Extremophilic halophiles. An organism that can live in a wide range of salinities is said to be euryhaline.
Natural sources:
- Water rain: This type of water carried in solution between 5 and 30 mg / L of salts, which represents an electrical conductivity between 8 and 50 dS / m and may reach 50 mg / L in coastal areas (80 dS / m).
- Edaphological origin: Several soil minerals can contribute significant amounts of salts to the soil solution. For example, in arid and semi-arid areas, these salts can come from minerals of evaporite origin such as some chlorides, sulfates and carbonates.
- Fossil salts: Its formation occurred under environmental conditions that favored the concentration and consequent precipitation of salts from waters of marine or continental origin. A clear example can be seen in the central part of the Ebro river depression, in the Monegros region (Aragon, Spain).
- Groundwater: In general; have a higher saline concentration than surface water mainly due to two reasons: prolonged contact, under favorable conditions, with rock minerals, as well as contact with saline sea water masses (marine intrusion) in coastal areas. In those areas where the phreatic levels are high, crops can receive important contributions of salts in the root zone, which can lead to significant soil salinization.
