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National Aquatic Resource Surveys

Indicators: Salinity

What is salinity?

Salinity is the dissolved salt content of a body of water. It is a strong contributor to conductivity and helps determine many aspects of the chemistry of natural waters and the biological processes within them. Salinity, along with temperature and pressure, helps govern physical characteristics of water such as density and heat capacity.

Why is important to measure salinity?

Salts can be toxic to freshwater plants and animals and can make water unsafe for drinking, irrigation and livestock watering. Excess salinity can occur in areas where evaporation is high and made worse by repeated use of water for irrigation or water withdrawals, where road de-icers are applied and in mining, oil and gas drilling and wastewater discharges.

What can salinity tell us about the condition of the water?

Salinity can be a chemical stressor in the aquatic environment as fluctuating levels of salinity can affect aquatic biological organisms which are adapted to prevailing salinity concentrations. Salinity is one of the primary factors used to identify whether a given study site is a part of an estuarine or coastal system.