This article will help you understand the various components of the hydrosphere and the concept of the hydrological cycle.

The Hydrosphere

It is a term used to describe the sum total of all water on earth, and it includes oceans, seas, lakes, streams and rivers, underground water, soil moisture, water vapor in the atmosphere, glaciers, and ice sheets.

Water is the only element that occurs naturally in three states – gaseous, liquid, and solid state. The chemical formula for water is H2O. The freezing point is O°C, while the boiling point is 100°C. Three-quarters of the surface materials on the crust of the earth consist of water.

Water also forms the largest part of most living matters. For example, an average man is two-thirds (2/3) of water; and plants manufacture carbohydrates with water. Plants also take their nutrients in solution.

Water is a universal solvent i.e. dissolves many substances and the solubility of water increase with increasing temperature. Water is also a very remarkable catalyst as many chemical reactions are slowed down or totally prevented when water is not available.

Water is also a geomorphic agent important for the process of weathering. Also, important in the process of weathering, modification, and formation of landforms (as water is an erosional agent). Water is the basis of life itself. It occurs in varying locations in the earth’s atmosphere
system.

Read Also: An Overview of The Environment and it’s Types

It is also involved in rain processes taking place within the earth’s atmosphere system. Because of the ubiquitous nature of water, we find out that water is studied by various disciplines. Some of the disciplines which study aspects of water include:

1. Hydrology

This is defined as the scientific study of water especially inland water both surface and underground, including its properties, distribution, movement, and utilization. (Inland water occurs over the land).

2. Hydrography

Is concerned with the description, survey, and charting of the oceans, sea, and coastlines together with the study of tides, currents, and winds
especially from the point of view of navigation.

3. Oceanography

Is the scientific study of all phenomena associated with the ocean. There are two branches of oceanography: (a) Physical and (b) Biological Oceanography.

Physical oceanography studies the extent and shape of the ocean basin, the structure, and relief of its floors, the movement of seawater, and its temperature and salinity.

While Biological oceanography is the study of life forms in the ocean including plants and animals.

4. Limnology

Is the scientific study of lakes, freshwater, and ponds. It deals with the various physical, chemical, and biological conditions and characteristics of water bodies. These four disciplines deal directly with water.

The level at which the troposphere gives way to the stratosphere is known as the Tropopause. The height of the tropopause from the earth’s surface varies from about 10 km around the poles to about 17 km at the equator.

The stratosphere starts from 10 km to 17 km above the earth’s surface and extends to a height of about 35 km. In this layer, air temperature increases gradually with increasing height.

Finally, the mesosphere gives way to the thermosphere at the boundary between the two layers referred to as the mesopause. The temperature within the thermosphere varies between 1100° and 1650°C.

The Hydrological Cycle

This is also known as the water cycle. This is the term used to describe the endless interchange of water between the ocean, air, and land. The cycle has no beginning nor an end. The hydrological cycle consists of two phases, the land, and the ocean phases.

In the land phase of the cycle, water is evaporated from the oceans and most of the moisture is adverted inland as vapor by air masses. The vapor later condenses to give precipitation on the land.

The falling precipitation is disposed of in various ways including -percolation (that is seepage into the ground); runoff (that is flowing through channels, and interception and reflection -which will be sent back to the atmosphere, or will eventually slide down to the surface.

Also, precipitated water finds its way to surface water, groundwater, or oceans and seas, where the process of evaporation begins all over.

The ocean phase is much shorter. Over the oceans, water is evaporated from the ocean surface into the atmosphere, the condensation of the vapor, and finally, the precipitation falls on the ocean surface.

Over the oceans; evaporation exceeds precipitation. The excess water vapor is therefore transported towards the land masses by atmospheric advection currents.

Whereas, over land, precipitation exceeds evaporation; the surplus land water is therefore transported to the oceans in the form of surface runoff through streams.

The Hydrosphere and The Hydrological Cycle