Some examples of the hydrosphere include seas, lakes, ponds and rivers. Hydrospheres are always in motion, and each has a different environment dictated by its contents.
The term hydrosphere describes areas of the earth that are aquatic, which is around 70 percent of it. This includes streams, rivers, ponds, lakes, oceans and seas. Although some hydrospheres may seem as though they are still, they are always in motion. It is easy to see this on the sea in the form of waves, while it is harder to see on areas like ponds on a calm day.
While the oceans and seas are made of salty water, other hydrospheres feature fresh water. Fresh water is central to sustaining life, but saltwater sources are far more common. While fresh water tends to be warm and light, salt water is dense because of the salt's presence, and it is cold. As such, salt water sinks to the bottom of its environment, while fresh water rises to the top.
As a hydrosphere, the ocean plays an important role in maintaining the earth's environment. It absorbs UV rays from the sun and redistributes the energy that arrives at the equator so it reaches other areas of the planet. It is able to do this because of the chemicals it contains.