Water,Nitrogen, Carbon And Phosphourus Cycles Essay, Research Paper

The carbon cycle deals with the interaction of carbon between living organisms and the nonliving environment. This cycle is a process through which all carbon rotates. The main result of the carbon cycle is to serve as a great natural “recycler” of carbon atoms.

The cycle works in a very basic way. First, carbon is taken from carbon dioxide found in the air. Plants take in carbon dioxide from the atmosphere. Plants absorb carbon dioxide from the atmosphere and use it, combined with water they get from the soil, to make substances they need for growth. The carbon is then mixed with water. Carbon dioxide is then formed into sugar (glucose). The process of photosynthesis incorporates the carbon atoms from carbon dioxide into sugars.

Animals attain carbon by feeding on plants and other animals. Animals eat the plants and use the carbon to build their own tissues. The animals get rid of the carbon dioxide in a process called respiration in which an organism supplies its tissues and cells with the oxygen and relieves the tissues and cells of carbon dioxide. Some animals, however, get rid of carbon dioxide only when they breathe, and when they die, the carbon is returned to the soil during decomposition. Carbon items continue to be recycled over and over. For instance the carbon atoms may then be used in a new plant or small microorganisms. Ultimately, the same carbon atom can move through many organisms and even end in the same place where it began. Combustion is another way in which carbon is returned into the atmosphere. Oil, gasses, wood and coal use this process. Molecules combine with oxygen and then convert into water and carbon dioxide and also release light and heat.

Humans play a very important role in the carbon cycle. Actually human impact can have a very negative effect on this cycle. Carbon dioxide is very important in the atmosphere, however only in moderation. For centuries humans have been burning coal, oil, and fossil fuels therefore releasing tons of carbon into the air. The problem with this is that this can cause a problem known as global warming. This is a major climate problem, which has series results on people and the environment. The result on people can be very deadly. Too much carbon in the air can cause cancer.

The nitrogen cycle is extremely important. This is because of the importance of nitrogen itself. Nitrogen is a basic element of life. It also makes up 78 percent of the Earth’s atmosphere. It forms an essential part of amino acids (which make up proteins) and DNA. Nitrogen is essential for all living cells.

The nitrogen cycle consists of 5 steps. First the basic element nitrogen in converted to ammonia. This process is called nitrogen fixation. This process is done by nitrogen fixing bacteria. Then the ammonia gets converted to nitrate. This process, called nitrification, is done by soil bacteria. Assimilation is the third step. Here the ammonia and the nitrate are absorbed by plants. Ammonification converts the nitrogen into ammonia. This process is done by ammonifying bacteria. The final step is denitrification. Here the nitrate is converted back to nitrogen. Denitrifying bacteria aid in this process.

Like all other elements, nitrogen is very important in life but in moderation. We sometimes cause an overload of nitrogen in the environment. When we cause nitrogen overload in our environment, there are many drastic effects. When large amounts of nitrogen collect in a water body there is an accumulation of excess nutrients, which causes an algae bloom. The algae rapidly use up all of the oxygen in the water, making it impossible for fish to live. Burning fossil fuels and wood contributes to a large amount of nitric oxide in the atmosphere. This can eventually form acid rain. The acid can damage trees and kill fish.

Unlike carbon and nitrogen, the Phosphorus cycle does not involve the atmosphere, rather it is found in sedimentary rock. Phosphorus is a necessary element in DNA, in many molecules found in living cells, and in the bones of many animals. A smaller source of phosphorus is found in the droppings (guano) of fish-eating sea birds.

Phosphorus enters the soil by the erosion of rocks. Then plant roots incorporate this phosphorus. Phosphorus is used in many biological molecules. Animals mainly through the food they eat obtain Phosphorous. Those foods that are high in phosphorus are beneficial to animals. Phosphorous is put back into the soil by decomposers.

Phosphorous cycle also involves the water. However, here the phosphorous must first dissolve before entering the water. Algae and plants take in this dissolved phosphorous. When they consume it bigger water animals consume them and so on and so on. Therefore the phosphorous is transferred over and over. Eventually the phosphorous is released by decomposers and used again. A minor part of that phosphate enters land and is absorbed by plant roots where it enters the land phosphorus cycle.

Humans have an effect on the phosphorous as well as the other cycles. However, in this cycle humans can speed up the long-term loss of phosphorus. This is because much of the absorbed phosphate ends up in human wastes and therefore ends up in our sewer systems. When the phosphate enters our sewer system this has a negative effect on our water systems. Since phosphate is being drained out of the land farmers must add fertilizers to the land.

The water cycle, or the hydrologic cycle, is the next cycle. Water is obviously the backbone of life. It is used in our day by day lives with out even noticing sometimes. This cycle consists of few steps.

The main source of energy for this cycle is the sun. First the sun heats the water. As this occurs, its molecules become energized. Then the water evaporates and rises as vapor in the atmosphere. This process is called evaporation. Next is the process called Condensation. As water vapor rises, it cools and eventually condenses, usually on tiny particles of dust in the air. It condenses when it hits the dew point. When it condenses it becomes a liquid again or turns into either ice, hail, rain, sleet or, snow. These water particles eventually come together and form clouds. Precipitation in the form of ice, rain, sleet, snow and hail comes from clouds. Clouds move around the world, propelled by air currents. Water vapor is also emitted from plant in a process called transpiration. Excessive rain or snowmelt can produce overland flow to creeks and ditches. Runoff is visible flow of water in rivers, creeks and lakes as the water stored in the basin drains out.

Bibliography

Sources Consulted

1. Environment textbook by Raven, Berg, Johnson

4. www.Encarta.com

5. http://library.thinkquest.org/11226