The Effect of Different Levels of Nitrate and Phosphate
on the Macroinvertebrate Populations in Different Streams
Phosphates and nitrates occur in small amounts in all aquatic environments and are required to maintain the growth and metabolism of plants and animals. However, in excess amounts, these minerals can prove to be quite harmful. Through the process of eutrophication, dissolved minerals and nutrients flow into streams, lakes, and other bodies of water. A good portion of these dissolved minerals consists of phosphates and nitrates. Levels of phosphates and nitrates that are intolerable to local organisms have been known to deplete dissolved oxygen levels by causing algae blooms. Eutrophication, bringing with it high amounts of phosphates and nitrates, is a main cause in the destruction of lake ecosystems around the world. (Ansar & Khad, 2005) Several scientists have studied mineral levels in different bodies of water, and have found that the levels of phosphates and nitrates heavily impact the overall health of the water and its inhabitants. (Yanamadala, 2005)
First one must understand exactly how organisms use phosphates and nitrates. Proteins in organisms require nitrogen to function. Nitrogen is a very common gas, making up about 79% of Earth’s atmosphere. However, living things cannot use nitrogen in this state. They must use nitrogen that has been fixed through nitrogen fixation, in which atmospheric phenomena, industrial methods, or certain bacteria transform the unusable form of nitrogen into useful nitrogen compounds. Plants use these compounds, and animals can acquire these compounds by feeding on the plants. Phosphorus is an essential element in DNA, ATP, and RNA, so it is needed by all living things. Plants use phosphorus to form more complex cells, and animals can get phosphorus by feeding on these producers. (Schmid-Araya, 2003).
How exactly does eutrophication indirectly affect aquatic life? It is already known that excess nutrients cause algal and bacterial growth. It also causes a burst of growth in plants and phytoplankton, forming a layer of green slime across the surface of bodies of water. This layer inhibits light movement into the water and also lessens the amount of oxygen that can get into the water from the air. Plants below the water’s surface may die from lack of light, and the resulting decay and decomposition of these plants causes the water to grow foul smelling and turbid. The loss of oxygen in the water causes aerobic organisms to suffer while anaerobic organisms are favored. More fish die from this loss of oxygen, and the total water quality of the water is lowered as the balance of life shifts. Eutrophic water is often scummy, cloudy, soupy-green in color, and overgrown with plants and algae. When an algal bloom resulting from phosphate and nitrate addition ends, the resulting decay of the algae often leads to the growth of disease-causing bacteria. Obviously, excess phosphates and nitrates significantly change the body of water for the worse. (Ansar & Khad, 2005)
In a recent study of bodies of water
near Morris Williams' Municipal Golf Course, located in
Increased levels of phosphates and
nitrates often indirectly harm the environment by causing bacterial growth and
huge algae blooms. (Yanamadala, 2005)
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