How do humans interfere with biogeochemical cycles - Essay Example

This nitrogen then travels to animals and humans when the plants are eaten, and is excreted as urine, which contains ammonia. Ammonia is poisonous, but autotrophic or nitrifying bacteria have the ability to oxidize it into nitrites and nitrates, which is the form of nitrogen that is most usable for plant metabolism.(CSuros, 1999:61). Similarly denitrifying bacteria have the ability to reduce nitrates to nitrous oxide and nitrogen, which can then be released back into the atmosphere. All of the above activities disturb the natural balance of nitrogen in the atmosphere and present within the soil.

Human beings have interfered with the natural progress of the nitrogen cycle by dumping large amounts of untreated sewage into water bodies, which when coupled with the urban runoff has produced an overload of nitrogen in aquatic systems. The net result of this excessive nitrogen in water is eutrophication, or the excessive growth of algae that in turn draw out all the oxygen in the water, so that other forms of marine life, such as fish, are unable to survive. (www.library.thinkquest.org). This also upsets the delicate, natural ecological balance of nitrogen that is maintained through the nitrogen cycle, which generally ensures the amount of nitrogen in the atmosphere at about 79%.

When eutrophication persists, then it produces a phenomenon referred to as the red tide, wherein the lack of oxygen in the water ca stifle and kill off any forms of life in the water. Atmospheric nitrogen is used by plants and the nitrogen excreted through the urine of plants and animals is fixed back into nitrates and nitrites using the nitrifying bacteria. But when excessive nitrogen is released through the dumping of too much sewage, it complicates issues by reducing the oxygen levels and thereby disturbing the balance of atmospheric gases as well.

Since oxygen is necessary for living beings to survive and the percentage of atmospheric oxygen needs to be maintained in order to