I already had listed some differences of salt water versus fresh water so here are some similarities;
Both- Change land through erosion
-are part of the water cycle
-can become polluted
-offer recreational use
-sustain life sources
-are used for transportation
-necessary part of life cycle
-algae develops in both systems
The water cycle contains the hydrosphere and the atmosphere. Both rivers and oceans play a vital role in the function of our planet. While fresh water has only 1% of salinity, it has salt content as well as an ocean has salt content. However, we already know that ocean water has a higher level of salt.
The greatest similarity between fresh and salt water is that both are basically the same chemical - water, although the contents of other materials dissolved in it differ.
Both contain some amount dissolved chemical in it though the quantities vary.
Both form different links in the water cycle of the nature.
Both are homes to aquatic life.
Salt water contains much higher quantities of dissolved chemicals as compared to fresh water. This higher concentration of chemical also raises the density of salt water above that of fresh water.
Plant and animals living in two types of water bodies are different.
Salt water is found only as large standing bodies of water. Most of these are in form of seas and oceans, although though some lakes including very large ones considered to be sea also contain salt water. Fresh water is found in standing bodies of water called lakes, as well as running water as in rivers and streams. Fresh water is available in many other forms such as in rain, and ice caps in the poles and in very cold places. However no fresh water is found in seas and oceans.
Fresh water is used for drinking as well as many industrial processes. However salt water is generally not suitable for most of the industrial use except for cooling. On the other hand salt water is used as a source of some chemicals, particularly common salt. Freshwater does not yield any such chemicals.