The term comes from the union of two Greek words: “ hydor ” (“water”), and “ sphaira ”, which can mean “sphere”.
This is one of the most dynamic layers of the Earth , since water is always in constant movement and changes in physical state .
Water circulates through many geographic spaces around the world. And it is that, this liquid covers almost three quarters of the Earth’s surface, only 3% of the water in the world is sweet.
The sun and the moon are very involved in the changes of state and the behavior of water. This can go from liquid to solid or gaseous state, or vice versa. Changes can be brought about by natural events or through the use of man-made tools.
On the origin of the hydrosphere, it is known that billions of years ago, when no organism still existed, it would be formed by the condensation and solidification of the water vapor existing in the primitive atmosphere, whose formation was due to the high temperatures that experienced the planet years before.
Mineral composition: the main salts are Cl – and Na + and to a lesser extent SO 4 -2 , Mg 2+ . In continental waters the anions CO 3 2- , HCO 3 – , SO 4 2- , Cl – and the cations Na + , K + , Ca 2+ and Mg 2+ are abundant .
Salinity : is the amount of ions dissolved in the water. The Mediterranean Sea accumulates 38 g / L, the Red Sea 40 g / L, the Dead Sea 226 g / L and the Baltic Sea has 5 g / L of salts.
Temperature variation: it is highly variable because it depends on the depth and latitude of the waters. Low latitudes have warm waters, while high latitudes have cold waters.
Density : pure water has a lower density than that of seas or oceans, this is due to the amount of salt present in the sea: the more salts, the more density. Temperature also intervenes: the higher the temperature, the less density.
Other characteristics of this layer is its amount of oxygen and its depth.
Functions of the hydrosphere
– It favors the regulation of the Earth’s temperature due to the buffering capacity of the water.
– It houses life manifested among the large number of organisms that live in seas, rivers, lakes and others. So it is essential to discuss the balance between the different layers of the Earth.
– Transforms and often improves environments thanks to erosion.
– Contains oxygen and other resources that can be used by many living beings.
Examples of hydrosphere
The hydrosphere is distributed as follows:
- Water on Earth: salt water or oceans (97%) and fresh water (3%).
- Fresh water : groundwater (30. 1%), ice from glaciers and ice surfaces (68.7%) and other types (0.9%).
- Surface fresh water: rivers (2%), swamps (11%) and lakes (87%).
The following are some examples of waters that make up the hydrosphere:
- Mekong .
- Yenisei .
- Huang He.
- Black Sea.
- Caspian Sea.
- Red Sea.
- Mediterranean Sea.
- Adriatic sea.
- Arabian Sea (part of the Indian Ocean)
- Cantabrian Sea.
- Caribbean Sea.
- South China Sea.
- Arctic Ocean.
- Antartic Ocean.
- Perito Moreno (Argentina)
- Taku (Alaska)
- Mer de Glace (France)
- Athabasca (Canada) …
- Jökulsárlón Glacier Lake (Iceland)
- Petermann (Greenland)
- Gray (Chile)
- The great Vatnajökull (Iceland)
Examples of lakes:
- Lake Superior (US and Canada)
- Lake Victoria (Kenya, Tanzania and Uganda)
- Lake Huron (Canada and United States)
- Lake Michigan (United States)
- Lake Baikal (Russia)
- Lake Tanganyika (Congo)
- Great Bear Lake (Canada)
- Lake Nyassa (Malawi, Tanzania and Mozambique)
- Great Slave Lake (Canada)