Water – A Wonder Liquid: Sources, Importance of Water, Water Cycle

The surface of the Earth is a complex zone in which the three main components of the environment meet, overlap and interact with each other. These are the land, the air, and the water in all three forms. Water is one of the most wonderful gifts of nature that constitutes the maximum part of the biosphere. Like air, water is vital to life as it regulates the physiological activities of animal and plant life. It is rightly phrased “Water: A Wonder liquid” as no living thing; neither plant nor animal can survive without this precious liquid. Do you know that water makes up 70% of our body and more than 80% of fruits and vegetables? Let us learn about the importance of water in sustaining life. For knowing the sources, daily uses of water, physiological significance and more, let’s read this article.

Sources of Water

Water is a colourless, odourless, tasteless universal solvent. It is a compound of two molecules of hydrogen and one molecule of oxygen.
Water occupies about 71% of the total Earth surface. 97.5% of the total water is the ocean. About 1.9% occurs as ice caps and glaciers. The remaining 0.6% of the hydrosphere supports life. It is called freshwater. Freshwater can be obtained from two main sources. These are:
1. Surface Water: Approximately 10% of the total freshwater occurs in the form of surface water. Rainwater that runs off on the surface of Earth is called surface water. It remains stored in small water bodies like ponds, pools, lakes, rivers, and streams.
2. Underground Water: Some of the rainwater seeps into the soil and accumulates down under the Earth’s surface. It is called underground water or subsoil water. It is pumped out using hand pumps and tube-wells for supply in towns and cities for domestic and agricultural use.

Uses of Water

We need water for various purposes. The main uses of water can be classified into household, agricultural, and industrial.
1. Household Use: Water is required in our daily life. We use water for drinking, bathing, cooking, cleaning, gardening. This makes us realise how much we depend on water in our daily activities.
2. Agricultural Use: A large amount of water is required for crop production. It is because a large amount of water is lost through transpiration. The amount of transpired water is, in fact, several hundred times greater than that is used by crops.
3. Industrial Use: Industries are often set up near the water bodies. It is because they need a huge amount of water. In a hydroelectric power plant, water is used to generate electricity. It is also used as a coolant.

Why is Water a Wonder Liquid?

Water is important not only to humans but for almost all living organisms in the world. Let us look at some examples to understand this better

Importance of Water in Plants

Water plays an essential role in plant life that can be mentioned under the following points:
1. Water contributes to plant growth and development as it is one of the main natural resources required for the germination of seeds. Seeds require an adequate amount of water and oxygen and germinate under suitable environmental conditions.
2. Water serves as a medium of transport for various dissolved substances like gases, minerals, organic substances through the xylem and phloem.
3. Water takes part in several metabolic reactions in plants, such as photosynthesis.
4. Water dissolved nutrients in the soil can be easily absorbed by the roots of the plant.
5. Water is the main constituent of the cell protoplasm. Therefore, it helps to maintain the shape (turgidity) of the cell.
6. Water also serves as a medium of heat transfer and therefore regulates the temperature.
7. A continuous water column is formed due to the transpiration pull that prevents the wilting of leaves.

Fig: Importance of Water in Plant Growth and Photosynthesis

Importance of Water in Humans

Potable water is safe to drink and maintain the proper functioning of the body that can be described as follows:
1. Water constitutes 83% of our blood, 75% of our brain, 22% of our bones, and 75% of our muscles.
2. Water is the main component of saliva. Our body produces enough saliva by the intake of water and other essential fluids.
3. Water helps to regulate the body temperature by the process of perspiration. During summers, the sweat glands release a large amount of water mixed with body salt (sweat); the evaporation of sweat causes cooling effects and helps to maintain a healthy temperature of the body.
4. Water is an essential medium for carrying all the metabolic reactions in our body. A healthy metabolism boosts the energy level of our body.
5. Water serves as a lubricant and cushion for our joints and spinal cord and protects them from external injury.
6. Water helps to excrete the wastes through urination, perspiration. Adequate intake of water keeps our kidneys healthy.
7. Water facilitates bowel movements and prevents constipation.
8. Water improves the circulation of oxygen through the blood and keeps the skin healthy.
9. Water maintains the osmoregulation and body pH.

Fig: Importance of Water in Humans

Water Cycle

The percentage of usable water is less than 1%. With such a limited supply of freshwater, why does our Earth not run out of fresh water? The secret behind this is the continuous circulation of water that is called the water cycle. The constant circulation of water from Earth’s surface to the atmosphere and from the atmosphere to Earth’s surface is called the water cycle.

Fig: Water Cycle

1. The heat from the sunlight evaporates the water from the water bodies.
2. The air containing water vapour is heated by the sun. Hot air is lighter, rises high in the sky.
3. Water vapour present in this air becomes condensed at high altitudes and converts into tiny water droplets.
4. The tiny water droplets join together to form large water droplets in the cloud.
5. These water droplets fall on the Earth in the form of rain.
In this way, the water which was taken from the Earth returns to the Earth. Although water keeps circulating in the biosphere, still the level of available water steadily goes down on the Earth. Keeping in view the shortage of usable water, we must put the greatest possible effects to conserve water. Rainwater harvesting is the best technique to save water.

Pollution of Water

Definition: Any undesirable change in the physical, chemical and biological properties of water that makes the water unfit for use is called water pollution.
Causes: The causes of water pollution include:
1. Sewage: Wastes from domestic activities such as detergents, human excreta are called sewage that is discharged directly into the water bodies and pollutes them.
2. Fertilisers & Pesticides (DDT, Polychlorinated biphenyls): These seeps into the groundwater through the soil pores and pollute the subsoil water.
3. Heavy metals: These metals mainly include mercury, cadmium, lead, and nickel. These metals disturb the normal pH of the water and make the water toxic.
4. Biological pollutants: These are microorganisms such as bacteria, viruses, protozoans, helminths, algae. These microorganisms consume oxygen dissolved in water. Hence the water becomes oxygen-depleted.
5. Oil spills: An accidental discharge of petroleum in the ocean is one of the major causes of water pollution.

Effects of Water Pollution

1. The solid wastes in the water (sewage) facilitate the growth of disease-causing microorganisms. When we drink this contaminated water, microorganisms enter the body and cause diseases such as cholera, typhoid, dysentery.
2. Fertilisers and pesticides accumulate in the groundwater and make it inappropriate for plants and therefore affect the growth and development of plants.
3. Heavy metal contamination of water can cause serious health problems. Mercury poisoning causes Minamata disease due to the consumption of mercury-containing fish. The metal wastes are also harmful to humans when they get absorbed in our bodies. They can damage the kidney, nervous system etc.
4. Organic wastes released in the water facilitate the multiplication of bacteria in the water that consumes the dissolved oxygen and, in turn, causes the death of other aquatic animals due to the lack of oxygen.
5. Oil spills in the water lead to the death of aquatic organisms and cause an imbalance in the aquatic ecosystem. These are extremely harmful to coral reefs and can severely damage marine biodiversity.
6. Thermal pollution is a type of water pollution in which the temperature of water bodies rises mainly due to the industrial effluents that adversely affect the health of aquatic animals.

Summary

Water is an inexhaustible natural resource that occupies the maximum part of the Earth. Water is the basis of our life. We cannot imagine our life without water. Apart from using water in our household activities, water supports several biochemical processes in living beings and delivers the substances to their target organs inside the organism’s body.

Moreover, water not only fulfils the purpose of daily activities and metabolic activities but itself is the main component of the plant and animal body. Due to these amazing facts, the title Water: A Wonder Liquid is wholly justified for this natural liquid.

Frequently Asked Questions (FAQs) on Water: A Wonder Liquid

The answers to important questions about water are provided here:

We hope this detailed article on Water: a Wonder Liquid helps you in your preparation. If you get stuck do let us know in the comments section below and we will get back to you at the earliest.