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Conductivity & Salinity


Conductivity is the amount of electrical current that can be carried by water. It is reported here in Siemens per meter.

In the 1930s, it was discovered that the electrical conductivity of seawater is proportional to its salinity. Conductivity is used to calculate salinity.

Recent Conductivity Measurements

Latest Conductivity


Seawater consists of a solution of inorganic salts, atmospheric gases, traces of organic matter, and small amounts of particulate material. Salinity is defined as the weight in grams of dissolved salt in 1 kg of seawater. Historically salinity was expressed in parts per thousand. In 1978, oceanographers redefined salinity in Practical Salinity Units (psu): the conductivity ratio of a seawater sample to a standard Potassium Chloride solution. The average ocean salinity is 35 psu. Estuaries have a salinity range of 0.5 to 30 psu.

Kennish, M. J., Practical Handbook of Marine Science, 2nd Edition, Boca Raton, Florida, CRC Press, 1994.
typical salinities
Typical salinities (PSU) of rivers, estuaries, and coastal waters.

Recent Salinity Measurements

Latest Salinity