Fig.1 The water cycle

The water cycle

The fig. illustrates the natural way the fresh water is recycled.  Fresh water flows in streams and rivers. Most of the suspended particles collected from the ground such as clay settle down gradually. Water coming down the slopes bubbling through the rocks gets oxygenated killing many microbes. UV rays from the sun too purify the water. The substances that dissolve cannot be removed by normal methods of sedimentation or filtration. These include the industrial waste and agricultural additives such as fertilizers and insecticides. At this stage water can be purified only by distillation. It is the sun that takes up this task. When the water evaporates the dissolved matter is left behind in the sea. So the purest form of natural water we get from the rain.

The demand for fresh water is forever rising. Even the stockpiles of ground water are being lifted up for large scale plantations resulting in desertification of certain regions. Surface water gets polluted; the natural cycle may not be able to cope up.  A partial solution has been found in desalination process but this consumes a lot of energy. If we are to survive man has to find more efficient ways of getting fresh water soon.

Carbon Oxygen cycles

Water, which was free at the beginning, has to be bought in most places. Today air is free for us to breathe. Will it continue to be so in the next millennium? The planet has only a thin layer of atmosphere which becomes thinner and thinner with altitude; Most of the living creatures need oxygen for respiration. They burn carbonic substances and exhale carbon dioxide into the atmosphere. Plants recycle this waste and return oxygen during photosynthesis.

Photosynthesis is the most important chemical reaction for us next to respiration. Plants contain a green pigment called chlorophyll. These have the ability to fix carbon dioxide gas and water to form food known as carbohydrates. These are compounds containing the elements, carbon, hydrogen and oxygen. Sugar, starch and cellulose are a few examples. The energy for this reaction has to come from light. As long as the sun shines, this process can go on.

Respiration is the opposite of Photosynthesis. Herein carbohydrates are converted to carbon dioxide and water releasing energy. While this is a very slow process which works at a low temperature burning is an identical chemical change working rapidly at a higher temperature. Respiration and photosynthesis can very well balance despite of calamities such as forest fires.  But as it has happened now, fossil fuels, oil and coal that have been accumulated from the carboniferous period, we are burning in an unprecedented manner. Now the scientists have sufficient evidence to believe that the human activity has caused the carbon dioxide levels to escalate.

The increase of carbon dioxide level in the atmosphere has caused a severe problem. This is a greenhouse gas. That means these molecules absorb more radiant energy than the oxygen and nitrogen molecules. This phenomenon causes the atmospheric temperature to increase with dire consequences such as sea level rise and extreme weather fluctuations…

Food Chain

Food can be defined as any substance taken in to supply energy or growth and maintain a healthy life. Carbohydrates, lipids, proteins, vitamins, and a few other elements constitute the food of all living creatures. Excepting for minerals and a few other essential elements, food is derived from glucose, produced by photosynthesis. In addition to Carbon and Hydrogen which comes from air and water protein synthesis require Nitrogen. Although air is rich in nitrogen plants cannot use it directly. Usually nitrogen is taken in from salts such as potassium nitrate, ammonium nitrate etc. which are present in the soil. Nitrates are returned to the soil in animal urine and by the decomposition of plant and animal matter. If the plants are burnt nitrates escape into the air.

As Mahathma Gandhi expressed, “The world has enough for every ones need but not for every ones greed” Most of the human beings are not merely reaping the wealth of the world but raping the resources. For example ‘The Internal Combustion Engine’, is not only exhausting the fossil fuel that has accumulated through the millennia but it also pollutes the environment. The process upsets the Carbon Oxygen balance and causes global warming. Wise men have been trying to create public awareness on this matter yet responsible states the higher institutions of education and research all over the world have paid only scant attention to the problem.