Question

What is salinity and how does it change?.

Answer 1

Salinity is controlled by a balance between water removed by evaporation and freshwater added by rivers and rain. changes in evaporation and rainfall, ocean currents, melting ice, and freshwater influx from rivers or streams can influence patterns of sea surface salinity, making some regions saltier and other regions fresher over time.

Answer 2

A balance between water withdrawn by evaporation and freshwater added by rivers and rain controls salinity. The Mediterranean Sea in Europe has a salinity of 38 parts per million or more. It's nearly cut off from the main ocean, and there's more evaporation than rain or additional freshwater from rivers.