Level 3
Introducing Salinity
Salinity is a measure of the amount of dissolved salts in water. In the open ocean, salinity varies little. Salinity in an estuary, however, varies according to location, tidal fluctuations, and the volume of freshwater runoff. Circulation and distribution of salinity are used to distinguish between different types of estuaries. Salinity may change from one season to another, depending on the amount of freshwater river flow or the change in weekly tides from spring to neap tides.
Below is a map of the Waquoit Bay National Estuarine Research Reserve showing the locations of four data loggers. Use this map to check your understanding. Then use real data to explore salinity levels in other reserves.
Check your understanding
