Lakes and ponds can be classified in many ways. One of the most common ways is by chemical composition. They may contain fresh water, salt water, or soda water.

Freshwater Lakes and Ponds

The water in freshwater lakes is relatively pure. Although it contains many dissolved minerals and salts, their concentration is very low. Freshwater lakes tend to be located in temperate or cold regions, and they support much plant and animal life.

Saltwater Lakes and Ponds

The salt found in salt lakes and ponds may be sodium chloride, which is ordinary table salt, or it may include a combination of other types, including magnesium salt. For example, the Great Salt Lake in Utah contains sodium chloride, whereas the Dead Sea between Israel and Jordan contains a combination of salts.

These salts usually enter the water as it dissolves the...